UP TGT Biology 2013 Official Paper (Previous Year Paper)

Concept: 

• A normal Human has 23 pairs of chromosomes (46 chromosomes) out of which 22 pairs are autosomes or allosomes (Non - sex chromosomes), while the 23rd pair is the sex chromosome which is responsible for the hereditary changes.
• One - One chromosome each in the sex chromosome pair comes from the maternal and paternal side respectively.
• Any deviation from this normal arrangement may result in a disorder or syndrome.
• These disorders may arise either by addition, deletion, or nonfunctioning of a single or multiple chromosomes.
• Examples of such disorders are Turner syndrome, Edward's syndrome, Patau's syndrome, Klinefelter's syndrome, etc.

Explanation:

• Turner's syndrome: It is caused due to the absence of one X-chromosome in the females i.e. Karyotype 45, (44 + XO).
• Such females are sterile with underdeveloped breasts, short stature, reduced ovaries & absence of menstrual cycle.

 

     

Klinefelter's syndrome:

• It occurs due to the trisomy of the X- chromosome in a male, resulting in a karyotype of 47, (44+ XXY).
• Individuals have long legs, sparse body hair, small prostate gland, small testes, reduced mental intelligence, and enlarged breasts (Gynaecomastia).
• Such individuals are sterile.

​

Concept:

The ear is a sensory organ, there are two main functions of ears

1. To receive sound waves, hearing
2. To maintain body balance.

Note ->

• Endolymph -> It is found in membranous labyrinth
• Perilymph -> It is fluid that surrounds the endolymph, located inside the bony labyrinth.

Structurally ear may be divided into three parts:-

External ear

• The external ear is divided into i) ear pinna, ii) ear canal which collects sound waves ad transport them to the middle ear.

Middle ear

• The middle ear or tympanic cavity has three ear ossicles i) malleus, ii) incus iii) stapes, these increase the efficiency of transmission of sound waves to the inner ear.

Internal ear

• The inner ear consists of two parts i) Bony labyrinth ii) Membranous labyrinth.

 

 

Explanation:

• The Membranous Labyrinth is a semi-transparent membrane.
• It is connected to the bony labyrinth by a cavity called the perilymph cavity. Perilymph liquid is filled in it.
• Endolymph is filled in the membranous labyrinth.
• There are two main bags like chambers in the membranous labyrinth**, utriculus**, and sacculus. Both these chambers are connected together by a thin canal called sacculo – utricular duct.

 

       

• Hemolymph is a fluid, analogous to the blood in vertebrates that circulates in the interior of the arthropod body remaining in direct contact with the animal's tissues. In cockroaches, the hemolymph is colourless.
• Lymph, pale fluid that bathes the tissues of an organism, maintaining fluid balance, and removes bacteria from tissues; it enters the blood system by way of lymphatic channels and ducts.

Concept:

• The stomata are minute pores that occur in the epidermis of the plants.
• Each stoma remains surrounded by two kidneys or bean-shaped epidermal cells the guard cells.
• The stomata may occur on any part of a plant except the roots.
• The epidermal cells bordering the guard cells are called accessory cells or subsidiary cells.
• The number and types of stomata vary in different plant species based on their Habitat.

Explanation:

• Xerophytes are plants found in the desert area.
• They require the least amount of water. In deserts there is a scarcity of water thus the plants have to take their water from the underground water level.
• Their stomata are of sunken type (deep-seated) like cup – shape depression as it helps them to prevent the loss of water through transpiration.
• Examples of xerophytes are – Aloe vera, Pineapple, Cactus, etc.

Additional Information

• Hydrophytes are plants that are either partially or fully submerged into water.
• Partially submerged hydrophytes like Lilly have stomata present on their upper leaf surface (lower pat is submerged in water).
• Fully submerged hydrophytes like water ferns do not have stomata, instead of stomata, the plant's surface cells are capable of absorbing water, nutrients, and dissolved gases in the water.
• Mesophytes have generally stomata present on the lower surface of the epidermis
• Examples are corn(maize), clover, cucurbit, etc

Concept:

Inflorescence:

• The arrangement of flowers on the floral axis is termed an inflorescence.
• The main axis of the inflorescence is known as the peduncle.
• The development of a flower on the old stem is known as cauliflory. Eg. Artocarpus.
• There are many different types of inflorescence like- Racemose, Cymose, Spike, Spadix, Corymb, etc.
• Some special types of the inflorescence are also there like Cyathium, Verticillaster, Hypanthodium.

Explanation:

Cyathium:   

• The bracts or the involucres become fused to form a cup-shaped structure, on the margin of it secretory glands are found.
• In the central part of the cup-shaped structure, a female flower is found, which matures earlier.
• Due to the growth of the pedicel, this flower comes out from the cup-shaped structure.
• The female flower is surrounded by small achlamydeous male flowers.
• The male flower, which lies towards the center mature earlier than the flowers which lie towards the periphery.
• Male flowers are represented by Stamens.
• This type of inflorescence is found in the Euphorbiaceae family - Euphorbia, Poinsettia, Pedilanthus.

• Racemose inflorescence: In this type of inflorescence, the peduncle (main axis or floral axis) is elongated and flowers are pedicellate.
• Examples - Radish, Mustard

Verticillaster:

• This type of inflorescence is found in Labiatae/Lamiaceae family.
• In this type of inflorescence, leaves are arranged in an opposite manner on the stem
• From the axil of each leaf, inflorescence develops.
• From the main axis, the lateral axis arises, on which flowers are found.
• Now from these branches, lateral branches develop also which bear flowers.
• In this type of inflorescence, each dichasial cyme changes into monochasia (scorpoid) cyme.
• Examples -   Labiatae/Lamiaceae family - Salvia, Ocium (tulsi)

 

Hypanthodium: 

• In this type of inflorescence, peduncle is modified into a narrow closed cup-like structure having a pore (ostiole).
• At the base of the cup female flowers develop while towards the mouth male flowers develop.
• All three types of flowers (male, female, sterile female) are present in this inflorescence.
• Examples - Ficus species - Banyan, Fig, Peepal

Concept:

• The larva is a stage in the development of many animals, occurring after birth or hatching and before the adult form is reached. These immature, active forms are structurally different from the adults and are adapted to a different environment.
• There are different types of larvas like Tonaria larva, Muller's larva, Tadpole larva, etc.

Explanation: 

• Balanoglossus belongs to the phylum Hemichordata.
• Animals of this phylum are worm-like, brittle, and soft.
• The body is divided into three-part:

1. Proboscis
2. collar
3. trunk

• The true notochord is absent, a notochord like structure is found in their buccal cavity called "buccal diverticulum" or "stomochord"
• Development is indirect. The animals have tornaria **larva (**planktonic larva)  just like bipinnaria larva of Echinodermata in their developmental stages.

Additional Information

Tadpole, also called polliwog, the aquatic larval stage of frogs and toads.

• Compared with the larvae of salamanders, tadpoles have short, oval bodies, with broad tails, small mouths, and no external gills.
• The internal gills are concealed by a covering known as an operculum.
• Tadpole larva shows retrogressive metamorphosis.

Muller's larva:

• A ciliated larva that resembles a modified ctenophore and is characteristic of various polyclad turbellarians (a subdivision of phylum Platyhelminthes).

Tornaria larva:

• Mulier proposed the name "tornaria". He considered it as Fxhinoderm larva.
• Metacoff first identified it as the larva of Balanoglossus
• This larva free swims in the seawater.
• It is oval in shape.
• It is transparent.

Concept​:

• Fossils are the preserved remains or traces of living things. These provide evidence of how life has changed over time.
• They also help scientists in knowing how Earth’s surface has changed.
• Fossils are clues to what past environments were like.
• Fossils can be divided into different types according to the process by which they are formed, or to the evidence, they have left behind.
• The method by which fossils are formed is termed fossilization.
• Some types of fossils include petrification, compression, impression, etc.

Explanation:

     Impression:

• An Impression fossil is the commonest form found in various types of sedimentary rocks, such as shales, sandstones, limestone's etc.
• These fossils represent only an imprint of the plant part. The original organic matter has been completely destroyed.
• The most common example of Impressions is the leaves of Glossopteris.

 

Compression:

• Compression Is only a degree of an impression when the organic remain of the plant part actually remain in the fossil but is highly compressed.
• The great pressure under which fossilization takes place flattens out all-round or solid organs so that what remains in the fossil is usually a carbonaceous film.

   

Petrification:

• It is the best but perhaps the rarest type of fossilization
• This literally means a transformation of the organic tissues into stone.
• The buried plant material absorbs mineral solutions like silicates, carbonates, phosphates, etc., and infiltration followed by precipitation takes place so that silica, calcium, carbonate gets impregnated within the tissues.
• Eg – Coal Balls

Virus:

• The name virus means venom or poisonous fluid was given by Pasteur. D.J. Ivanowsky.
• It is a microorganism that is smaller than a bacterium that cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself

.Spores:

• Reproductive cell capable of developing into a new individual without fusion with another reproductive cell. Spores thus differ from gametes, which are reproductive cells that must fuse in pairs in order to give rise to a new individual.
• Spores are agents of asexual reproduction, whereas gametes are agents of sexual reproduction. Spores are produced by bacteria, fungi, algae, and plants.

Bacteria: 

• These are microscopic prokaryotes.
• They are the sole members of kingdom monera.

Concept:

• The egg of a chick is telolecithic type because it contains a large amount of yolk at one end.
• The living part of the egg is restricted to the upper pole of the yolk which is known as blastodisc or germinal disc.
• Development and differentiation of a chick's embryo start by cleavage.
• Cleavage is the repeated division that occurs in the blastodisc  region
• The first two cleavages occur at the right angle to each other in a vertical plane which results in the formation of four cells.
• The third Cleavage occurs in the horizontal plane which results in the formation of eight cells.
• The remaining cleavage is irregular as a result 256 irregular cells are formed.
• Cleavage is followed by blastulation and gastrulation, which results in the differentiation of chick embryo into three germinal layers 1) Ectoderm 2) Endoderm 3) Mesoderm.
• Primitive streak (groove along the anterior-posterior axis) starts to form, which is observed at different stages like 18 hrs, 23 hrs, 33 hrs,48 hrs, 72 hrs, etc

 

Explanation: 

33 hrs Chick embryo:

• Primitive streak restricted to the posterior end.
• Head bent ventrally.
• Neural folds fused in the brain region except for the neuropore.
• Three primary brain vesicles, prosen­cephalon, mesencephalon, and rhom­bencephalon differentiated.
• The notochord is distinct.
• Foregut elongated.
• Heart rudiment tubular and bent to the right.
• Somites 10 pairs.

 

48 hrs Chick embryo:

• Primitive streak greatly reduced.
• Amnion in a very early stage.
• Both cranial and cervical flexure deve­loped.
• Neural tubes differentiated into the brain and spinal cord.
• Optic cups are prominent.
• Auditory vesicles are distinct.
• Three pairs of arterial arches arise from the ventral aorta.
• Somites 26 pairs.

 

 

72 hrs chick embryo:

• The cranial flexure is maximum.
• Appendage rudiments present.
• Optic cups with distinct, closed retina and leaves.
• Auditory vesicles connected to the ectodermal aperture through ductus endolymphatic.
• Somites 35 pairs

 

Concept:

• Blood is a connective tissue, that has an iron-containing pigment called Haemoglobin.
• The haemoglobin gives a red colour to the blood and is responsible for the transport of O₂ molecules throughout the body.
• One heme group can carry 4 O₂ molecules at a time. Heme group remains in the ferrous state (fe²⁺) in normal conditions.
• When haemoglobin combines oxygen from the lungs it forms oxyhaemoglobin.
• Oxyhaemoglobin transports oxygen to the cells of the body.
• Oxygen gets attached to Haemoglobin because it shows an affinity towards it, but other gases such as carbon mono-oxide (CO), carbon dioxide (CO₂) also shows an affinity towards it.

 

Explanation:

• When the outside environment is rich in CO, and it is being inhaled, it starts to displace oxygen bind on Haemoglobin.
• The displacement occurs because CO shows several hundred times stronger affinities towards haemoglobin than oxygen, and it forms carboxyhaemoglobin.
• This leads to the scarcity of oxygen in the body, and sufficient oxygen is not available for the mind and other organs.
• Concentrations as low as 20 or 30 parts per million (PPM) can be harmful if exposed for several hours.
• Exposure at 2,000 PPM for one hour will cause unconsciousness.
• The increased concentration of carbon mono-oxide also leads to depletion of Ozone however, this is not the direct reason for why CO is harmful to humans

Carcinogens:

• These are the cancer-causing agents, they promote carcinogenesis.
• Carcinogens stimulate normal body cells to become cancerous cells, and due to uncontrolled growth of these cells tumours are formed.
• The three main types of carcinogens are:
• chemical carcinogens, physical carcinogens, and oncogenic (cancer-causing) viruses.

Concept:

• Prokaryotes are those which consist of a single prokaryotic cell.
• Pro (means primitive), so these organisms do not have advanced cellular features like membrane-bound organelle, nuclear membrane, 80s ribosomes, etc.
• Examples of prokaryotes are bacteria and archaea.
• Eukaryotes are multicellular organisms with eukaryotic cells.
• These organisms have all advanced cellular features.
• Examples of eukaryotes are protists, fungi, plants, and animals (everything except prokaryotes).
• A major difference between a prokaryotic and eukaryotic cell is as follows.

 

Explanation:

• T.M.V (Tobacco mosaic virus), is a virus and it cannot be placed either in the eukaryotes or prokaryotes because a virus does not have any characters of living things.
• It requires a host body to complete its replication, without the host it is considered Non-living.
• And it is well known that anything which doesn't have its independent existence cannot be considered a cell be it be prokaryotic or eukaryotic.

 

        

NOTE- A virus is considered a connecting link between Living and Non-living things.

Nostoc:

• It is a prokaryotic cell as it lacks the true nucleus and other eukaryotic characters.
• It is called cyanobacteria or blue-green algae.
• The main function of Nostoc is to fix atmospheric nitrogen with the help of specialized cells called Heterocyst.

Chlamydomonas:

• It is a unicellular green alga(eukaryote)
• It contains higher photosynthetic pigments like chl.a and b, so it is capable of producing its food

Saccharomyces

• It also called yeast is a fungus. It is a eukaryote.
• It is heterotroph (depend on others for their food), and it reproduces by budding.

Concept

• Excretion is the process of removal of nitrogenous wastes from the body of an organism.
• Nitrogenous waste can be divided into three groups based on its toxicity.

1. Ammonia – animals secreting ammonia are called Ammoneotelic
2. Urea - animals secreting Urea are called Ureotelic
3. Uric acid - animals secreting Uric acid are called Uricotelic

• Excretion is performed by a specialized group of cells or organs called excretory organs.
• Different organisms have a different type of excretory organs
• Example: 1) Flatworms – Protonephridia,  2) Earthworms – Nephridia,  3) Insects – Malpighian tubules,  4) crustaceans – green glands, 5) All chordates - Kidneys

 

Explanation:

• In Herdmania there is an oval-shaped neural gland that is brown in color lying just above the brain. It is encapsulated in the mantle, in the intersiphonal region. It is about 4 × 1 mm in size. The neural gland has several branching tubules, which open into a non-ciliated canal running along the complete length of the gland.
• It leads into a tiny duct that opens by a ciliated funnel at the base of the dorsal tubercle ( a small round projection on the surface) in between two lobes. Nephrocyte cells of the blood collect waste material, mainly xanthine and urates. They enter the lumen of the neural gland from where they pass out into the pre- branchial zone of the pharynx.

 

         

• Solenocytes are also known as Flame cells are the excretory structures found in Platyhelminthes.
• They are meant for excretion and osmoregulation.
• The Solenocyte bears a Flagellum, which blows excretory products along the tubule.
• A ganglion is a cluster of nerve cells found in the peripheral nervous system. The cells that are specific to a ganglion are called ganglion cells.

Concept:

• Different Plants use different photosynthetic processes for atmospheric carbon fixation.
• The three main processes are

1. C3 cycle – Wheat, Rice
2. C4 cycle – Maize, Sugarcane, Sorghum
3. CAM pathway – Bryophyllum, Opuntia, Agave

• Based on these processes plants are divided into C3 plants, C4 plants & CAM plants.
• Leaves of C4 plants possess specialized structures where the mesophyll cells are clustered around the bundle sheath cells in a ring-like fashion.
• This type of arrangement is called  ‘’KRANZ Anatomy’’

 

  

 

Explanation:

• Leaves of C4 plants possess Kranz (Wreath) anatomy.

1. Green bundle sheath cells present around the vascular bundles.
2. Dimorphic chloroplasts present in leaf cells. The chloroplast of bundle sheath cells or Kranz cells is larger and without grana. Mesophyll chloroplast is small and with grana.

• This Kranz anatomy plays a vital role in C4 photosynthesis.
• In C4 plants the initial fixation of carbon dioxide from the atmosphere takes place in the densely packed mesophyll cells.
• After the carbon dioxide is fixed into a four-carbon organic acid, the malate is transferred through tiny tubes from these cells to the specialized bundle sheath cells.
• Inside the bundle sheath cells, the malate is chemically broken down into a smaller organic molecule, and CO₂ is released.
• This carbon dioxide then enters the chloroplast of the bundle sheath cell and gets fixed a second time with the action of enzyme Rubisco and continues through the C3 pathway.
• Thus, carbon dioxide is fixed twice and this increases the efficiency of C4 plants over C3 plants.

 

          

Important Points

• Kranz anatomy is the characteristic feature of the c4 plants.

Concept:

• Peristome derived from greek word – ‘peri’ meaning ‘around’ and ‘stoma’, meaning mouth.
• The peristome is a teeth–like projection that surrounds the mouth of the capsule in most of the members of Bryidae (Mosses) of bryophytes. So, it is an important characteristic of Bryopsida.
• The peristome teeth spring from the rim or diaphragm.
• The peristome teeth are triangular two-ply structures that operate like trap – doors.

Functions:

• Peristome teeth serve as a valve that allows the spores to exit the capsule.
• The peristome teeth open and spread outwards during times of low humidity, allowing the spores to float away and disperse. One layer readily absorbs and releases water, while the other layer does not react much to varying humidity levels.
• This causes the teeth to bend outward during times of low humidity.

Mainly Peristome teeth are of two types:

1. Orthodontous
2. Nematodontous

 

Explanation:

• Funaria belongs to the group Bryophyta.
• Funaria is a type of Moss commonly called Rope moss or Cord moss.
• Its sporophyte is divided into Foot, Seta, and Capsule.
• The capsule has a layer called an operculum, which has 32  teeth, arranged in 2 rings of 16 teeth each
• These peristome teeth are of Arthodontous type (when there are 16 teeth in each peristome)

 

        

Additional Information

• Nematodontous – In nematodontous peristome, the teeth of peristome are solid, composed of bundles of dead cells.
• Eg – Polytrichum, Pogonatum

Concept:

• Development and differentiation of a chick's embryo start by cleavage.
• Cleavage is the repeated division that occurs in the blastodisc region
• The first two cleavages occur at the right angle to each other in a vertical plane which results in the formation of four cells.
• The third Cleavage occurs in the horizontal plane which results in the formation of eight cells.
• The remaining cleavage is irregular as a result 256 irregular cells are formed.
• Cleavage is followed by blastulation and gastrulation
• Gastrulation begins within four or five hours after the onset of incubation and is completed in about 22 hours.
• It brings out a definite shape to the embryo. Gastrulation in chick embryos can be divided into two phases.
• Endodermal formation
• Primitive streak formation

Formation of endoderm:

• The endoderm of the hypoblast develops as a single layer of cells inside of the blastocoel. After the formation of the endoderm, the upper layer is called the epiblast.
• Formation of primitive streak; The second step in gastrulation is the formation of a primitive streak.

The primitive streak has a:

• Primitive groove
• Two primitive folds
• A Hensen’s node
• A primitive pit
• A primitive plate

 

Explanation:

• At the anterior end of the primitive groove, a mass of densely packed cells is present. It is called ‘’Hensen’s node’’ or Primitive knot.
• This node is the site where gastrulation and the formation of the three germinal layers, initially begins.
• The node determines  the anterior-posterior axis of the embryo by directing the development of the chordamesoderm
• The chordamesoderm is a definite type of mesoderm that will differentiate into the notochord, somites, and neural tube.
• These structures will later form the vertebral column.
• It is called Hensen’s node in chick embryo after its discoverer’s name Viktor Hensen

 

        

Concept:

• Paleobotany is the scientific study of plant and animal Fossils that involves the analysis of plant and animal fossils, including those of microscopic size, preserved in rocks.
• It is concerned with all aspects of the biology of ancient life forms: their shape and structure, evolutionary patterns, taxonomic relationships with each other and with modern living species, geographic distribution, and interrelationships with the environment.

Explanation:

• Prof. Birbal Sahni was an Indian paleobotanist who studied the fossils of the Indian subcontinent.
• He founded the Birbal Sahni Institute of Palaeobotany at Lucknow in 1946.
• Sahni worked on living plant species including Nephrolepsis, Niphobolus, Taxus, Psilotum.

• Prof. Shiv Ram Kashyap is called the father of Indian Bryology. The study of Bryophytes is known as Bryology.
• Professor K.C. Mehta is one of the eminent scientists of India. He has contributed a lot in the field of plant pathology.
• Plant pathology is a branch of science which deals with the study of diseases in plants that are caused by pathogens.
• Prof. J.C Bose was a biologist, botanist, and physicist. He has done commendable work in the field of radio science and he has been named as one of the fathers of radio science by IEEE
• He invented an instrument called crescograph to measure plant response to various stimuli, and thereby scientifically proved parallelism between animal and plant tissues.

Concept:

• Elaters are ribbon-like or tube-like structures that are attached to the spore walls. They are sterile cells.
• Elaters are hygroscopic (can absorb water) in nature.
• Their main function is the dispersal of spores as they push the spores out of the plant by absorbing moisture.
• Elaters are majorly found in Bryophytes, like elaters in hepaticopsida and pseudo-elaters in anthoceropsida.
• However, some forms are also seen in Pteridophytes such as Equisetum.

Explanation:

• Equisetum (Pipe) belongs to the class Sphenopsida of group Pteridophyta.
• They are commonly called Horsetails.
• Their main plant body is differentiated into root, stem & leaves.
• Roots are adventitious.
• Their stem Is jointed i.e. nodes and internodes are seen on the stem. Scaly leaves are present on these nodes.
• In Equisetum, elaters are four ribbon-like appendages attached to the spores. These appendages develop from an outer spiral layer of the spore wall. At maturity, the four strips peel away from the inner wall, except at a single point on the spore where all four strips are attached.
• Under moist conditions, the elaters curl tightly around the spore. The wet spores tend to stick to each other and nearby surfaces because of surface tension. When conditions are dry, the spores no longer stick to each other and are more easily dispersed.

   

Additional Information

Selaginella:

• Also called Little club moss or spike moss or Bird’s nest moss.
• Most of the species of selaginella are ‘’Drought Escapers’’, so they are called Resurrection plants.
• Selaginella has fertile leaves called sporophylls, which bear two types of sporangia – microsporangia and megasporangia.
• Spores are dispersed from these sporangia.

Lycopodium:

• Belongs to the class Lycopsida of group Pteridophyta.
• Commonly called club moss.
• The sporophytic plant body of Marsilea shows the differentiation of stem, leaves, and roots.

Key Points

• In Pteridophytes, the annulus and the stomium help in the dehiscence of the sporangium and dispersal of spores. Stomium is a thin row of cells on one side of the capsule, which marks the line of dehiscence. At maturity, the sporangium dehisces by drying action, which exerts pressure on the mouth assisted by shrinkage of the annulus. Lastly, the mouth of the sporangium opens, and the spores are liberated.

Concept:

 

• Kidneys are the excretory organs in majority of mammals including humans

• Kidneys regulate water and electrolyte balance (osmoregulation) along with the excretion of metabolic waste and foreign chemicals. 

• The functional units of mammalian kidneys are called Nephrons.

• These nephrons perform the function of filtration of blood and deposition of the urine in the collecting duct.

 

Explanation: 

 

• The loop of Henle or Henle’s loop is a hairpin-like structure present between Proximal Nephron (PCT) and Distal Nephron (DCT)

• • The main function of Henle’s loop is to selectively reabsorb water and other important salts like NaCl, this makes the urine more concentrated.

 

 

Additional information:

 

• The heart is the pumping organ of our body that circulates blood throughout the body

• The liver regulates most chemical levels in the blood and excretes a product called bile. This helps carry away waste products from the liver. 

• Lungs perform the function of breathing.

Concept:

• Biological control can be defined as the process of using natural predators (natural enemies) of pests, insects, mites, etc. to control their population.

Explanation:

• The fish Gambusia affinis (mosquito eater)  is one such bio-control agent, which feeds on mosquito larva.
• Thus it helps in checking the population of mosquitos.
• A fully grown fish can eat 100-300 mosquito larva per day.
• It serves as a great biocontrol agent for mosquitos because it is small in size, easily culturable, and can tolerate saline conditions.

Additional Information

Rohu:

• It is a freshwater river fish, that is commonly found in South Asian countries like India, Pakistan, Bangladesh.
• It is rich in vitamin a, b, c, and omega 3 fatty acids. It keeps the skin healthy and checks cholesterol levels.

Concept:

• Bacteria are prokaryotic cells i.e they lack a true membrane-bound nucleus.
• The bacterial genetic material lies naked in the cytoplasm.
• Bacteria have supercoiled circular ds-DNA called the Genophore (nucleoid), which is its primary genetic material
• Along with Genophore bacteria also have extrachromosomal genetic material called the ‘’Plasmid’’.

 

Explanation:

• The plasmid was discovered by William Hays and Joshus Lederberg (1952)
• These are small, double-stranded, closed circular, symbiotic DNA molecules that occur naturally in bacteria, outside the bacterial chromosome.
• They are regarded as extra-chromosomal DNA containing an extra-chromosomal genome.
• A bacterial cell may possess one or many copies of one or more plasmids.
• They are inherited from parent bacterial cells to daughter cells and have the capability to self-replication in the cytoplasm of the bacterial cell.
• They vary in size from 2 kilobars to 400 kilobars.
• Eg – pBR322 (cloning plasmid)

 

 

Additional Information

• Proteinaceous part of the virus is its covering called Capsid
• The nuclear part of the virus contains genetic material either DNA or RNA, no virus has both DNA and RNA at the same time

Concept:

• Excretion is the process of removal of nitrogenous wastes from the body of an organism.
• Nitrogenous waste can be divided into three groups based on its toxicity.

1. Ammonia – animals secreting ammonia are called Ammoneotelic
2. Urea - animals secreting urea are called Ureotelic
3. Uric acid - animals secreting uric acid are called Uricotelic

 

 

Explanation:

• Ammonia is a water-soluble highly toxic nitrogenous waste, and it requires plenty of water for its removal
• Frog’s Tadpole is aquatic and lives in water so, nitrogenous wastes are eliminated in the form of ammonia.
• Adult frog has an amphibian habitat so it requires a lower amount of water for its waste removal, so the waste is removed in the form of Urea.

Concept:

• The respiratory Quotient is defined as the ratio of the volume of CO₂ liberated for the volume of O₂ consumed.
• The value of R.Q.  depends upon the type of respiratory substance utilized & measured by the device Ganong’s respirometer.

Explanation:

• The R.Q. of Carbohydrates is 1

C₆H₁₂O₆  + 6O2 +6H₂O 

 6CO₂ + 12H₂O + E

• The R.Q. of fats/oils is  0.70 or  R.Q.<1
• The R.Q. of proteins is 0.8 or 0.9 or <1
• R.Q in anaerobic respiration is infinite/ ∞

Concept:

Lamarck’s theory of evolution or Lamarckism:

• According to Lamarck, the evolution of life occurred due to the use and disuse of organs.
• He explained it in his famous book ‘’Philosophie Zoologique’’ in 1809.
• This theory is no more accepted today.

Explanation:

Lamarck’s theory is based on three factors:  new needs, acquisition of characters, and inheritance of acquired characters.

• New needs: The environment means the aggregate of external circumstances, conditions, and things that affect the existence and development of organisms living there. Variation in the environment creates a need for adapting to change, else it will not survive. The organisms thus have to put special efforts to fulfill the need for adaptation and this will lead to change in the habits and behavior of organisms.
• Acquisition of characters: characters are acquired by the organisms to meet the new needs in three ways: innate tendency, use and disuse of organs, and effects of the environment.
• Inheritance of Acquired Characters: The characters acquired by an individual through the use and disuse of organs and environmental influences are transmitted by the heredity to the next generation. In every generation, fresh characters are acquired. As the result, after a number of generations, the variations accumulate to the extent that the species is modified into a new one.
• Eg –Giraffes initially did not have long necks. But to access leaves on tall trees, they had to adapt by elongating their necks. By passing this acquired character to the succeeding generation, they acquired long necks.

 

   

Additional Information

• Mutation: It is defined as the change of gene sequence in the organism’s genome by deletion, addition, or translocation such that it alters the genetic message carried by that gene.
• Natural selection was given by Charles Darwin, according to it those populations which are a better fit (reproductively fit) in an environment will be selected by nature and will survive more.

The correct answer is Doubled layered.

Concept:

• Cell organelles are surrounded by an envelope or covering called a membrane.
• Based on the presence or absence of these membranes cell organelles can be grouped into different categories.
• No membrane - Ribosomes, Nucleolus
• Single membrane - Lysosomes, Golgi bodies, Endoplasmic reticulum, etc.
• Multiple membranes - Nucleus, Mitochondria and chloroplast are double membrane-bound.

Explanation:

Chloroplast:

• The chloroplast is a double membrane-bound cell organelle.
• Out of the two membranes, the inner membrane is relatively less permeable. (the outer membrane contains porins).
• The space limited by the inner membrane is called the stroma.
• Chloroplasts contain chlorophyll and carotenoid pigments which are responsible for trapping of light energy essential for photosynthesis.
• The majority of chloroplasts are found in the mesophyll cells of the leaves.

Important Points

• Chloroplasts have their own genetic system & complete protein synthesis machinery (ds - DNA, RNA, Ribosomes, Enzymes, Amino acids) thus chloroplast is also called semi-autonomous organelle.

Concept:

• The nerves which arise from the brain are called the cranial nerves.
• Humans and other mammals have 12 cranial nerves.
• There are 3 types of cranial nerves based on their action
• Sensory
• Motor
• Mixed

 

Explanation:

• Trigeminal (Dentist's nerve): It is the largest cranial nerve.
• It has both sensory and motor functions,
• These nerves have 3 basic divisions:

 

 

    

Additional Information

Optic nerve:

• It leads to the occipital lobe. and is responsible for sight

Olfactory nerve:

• It enters the Olfactory lobe, Extends to the temporal lobe.
• It is responsible for the smell sensation

Important Points

• The longest cranial nerve is the Vagus nerve
• The largest cranial nerve is the Trigeminal nerve.
• The smallest cranial nerve is the Abducens cranial nerve

The correct answer is- Air pollution

Key Points

Concept:

• The term ''Lichen'' was given by Theophrastus.
• Study of Lichens - Lichenology.
• Father of Lichenology - Erik acharius
• Lichen is a composite thalloid structure of algae & fungi.
• The algal part of Lichen is called phycobiont and the fungal part is called mycobiont. Both algae & fungi remain in symbiotic association i.e. they are beneficial for each other.

Explanation:

• Lichens are good indicators of air pollution – Lichens are sensitive towards SO₂(sulphur dioxide). They die in more concentration of SO₂. Therefore they are not found in those areas (polluted areas) where the concentration of SO₂ is high.

Additional Information

Other ecological importance of Lichen:

1. Many Lichens are used as food and fodder. Eg –Parmelia, used as food in South India. It is known as Rock Flower.
2. It is also used as dyes. Eg – Litmus(Acid-base indicator) is obtained from many members of lichens like Roccella tinctoria.
3. The crustose and foliose lichens grow on rocks and secrete different types of acids These acids break the rocks. In this way, these lichens help in soil formation.

Explanation:

• Thescocytes are the cells that store food (glycogen). These cells have bulbous or thick pseudopodia.
• Pinacocytes are flat cells that form the outer ectoderm or pinacoderm.
• Choanocytes are the collar cells, that form the inner layer of the sponge body (Choanoderm). These are the characteristic cells of sponges (Porifera)
• Choanocytes with flagella form the lining of spongocoel and some canal.
• Trophocytes are the cells that are involved in the digestion and distribution of food. They are also called nurse cells as these are involved in the initial stages of gemmule formation

 

 

Additional Information

• Sponges belong to the phylum Porifera.
• These are primitive multicellular animals. The study of sponges is known as Parazoology.
• Sponges are mostly irregular in shape and have Radial symmetry.
• Sponges have a cellular level of organisation and with two germ layers i.e**. Diploblastic**

Concept:

• Asexual reproduction is a mode of reproduction in which new offsprings are produced by a single parent without the involvement of gametes or fertilization.
• Offspring produced by such reproduction are genetically identical copies of the parents.
• Asexual reproduction is of the following types:
• Binary fission
• Budding
• Fragmentation
• Gemma-cup formation
• Spore formation
• Vegetative propagation.

 

Explanation:

• Asexual reproduction in Marchantia (Liverwort) takes place by fragmentation of thalli, or by the formation of specialized structures called gemmae (sing. Gemma).
• Gemmae are green, multicellular, asexual buds, which develop in small receptacles called gemma cups located on thalli.
• The gemmae become detached from the parent body and germinate to form new individuals.

 

   

 

Additional Information

• Asexual reproduction in Funaria (Mosses) occurs by fragmentation and budding in secondary protonema
• Pogonatum reproduces asexually by fragmentation.
• Riccia may reproduce asexually by adventitious branches or tubers.

Concept:

• Chromosomes are a highly condensed form of chromatin threads.
• Chromosomes were first observed by Hofmeister (1818) and Karl Nageli in pollen mother cells of Tradescantia.
• Strasburger described chromosome structure first appeared in the nucleus during cell division

 

Explanation:

• Chromosomes are grouped into 4 categories based on the position of the centromere.

1. Telocentric: When the centromere is terminal or located at the tip of the chromosome. These are I - shaped
2. Acrocentric: when the centromere is sub-terminal or located near the tip. These are J-shaped.
3. Metacentric: When the centromere is located at mid of the chromosome. These are V-shaped.
4. Sub metacentric: When the centromere is located near the centre or midpoint of the chromosome. These are L-shaped.

 

 

 

Additional Information

• The number of Acrocentric chromosomes in Humans are 13, 14, 15, 21, 22, and Y
• The number of Sub-metacentric chromosomes in Humans are 2, 4, 12, 17, 18, X

Concept:

• Peristome derived from greek word – ‘peri’ meaning ‘around’ and ‘stoma’, meaning mouth.
• The peristome is a teeth–like projection that surrounds the mouth of the capsule in most of the members of Bryidae (Mosses) of bryophytes. So, it is an important characteristic of Bryopsida.
• The peristome teeth spring from the rim or diaphragm.
• The peristome teeth are triangular two-ply structures that operate like trap – doors.

Functions:

• Peristome teeth serve as a valve that allows the spores to exit the capsule.
• The peristome teeth open and spread outwards during times of low humidity, allowing the spores to float away and disperse. One layer readily absorbs and releases water, while the other layer does not react much to varying humidity levels.
• This causes the teeth to bend outward during times of low humidity.

 

Explanation:

• Peristome teeth are a characteristic feature of Mosses.
• For example, Funaria (Rope moss or Cord moss) has 32 peristome teeth arranged in 2 rings of 16 teeth each embedded in the Operculum layer of the capsule.
• The peristome teeth in funaria are of Arthodontous type (when there are 16 teeth in each ring)
• Polytricum has Nematodontous type peristome teeth.

 

   

 

Additional Information

• Liverwort (Hepaticopsida) and Hornwort (Anthoeropsida) are the two classes of Bryophytes along with the Mosses (Bryopsida), but they do not have Peristome teeth

Explanation:

• An ecosystem is the basic ecological unit in which living organisms interact among themselves and with their surrounding physical environment.
• Except for the deep sea hydro-thermal ecosystem, the sun (sunlight) is the only source of energy for all ecosystems on earth.
• Out of the total incident solar radiation, only 50% of it is photosynthetically active radiation (PAR).
• Plants capture only 2-10 per cent of the PAR and this small amount of energy sustains the entire living world. So, there is the unidirectional flow of energy from the sun to producers and then to consumers.
• The energy is transferred in an ecosystem in the form of food which is degraded and lose a major part of food energy as heat during metabolic activities, this can be explained by Lindeman’s 10 per cent law which says only 10% of energy is transferred from one trophic level to the next higher trophic level.

  

 

Additional Information

• Glucose is a simple sugar with the molecular formula C₆H₁₂O₆. Glucose is the most abundant monosaccharide.
• Proteins are long chains of amino acids that are interconnected by peptide bonds.
• A.T.P is the energy currency of cells produced in mitochondria, these are required for various biochemical processes.

Concept:

Classification of Riccia:

Division – Bryophyta

Class – Hepaticopsida

Order – Marchantiales

Family – Ricciaceae

Genus – Riccia

 

• Riccia belongs to the class Hepaticopsida of Bryophyta. It is distributed widely across the temperate and tropical regions of the world.
• There are about 138 species of Riccia known worldwide and about 28 Indian species are there.
• All the species of Riccia are terrestrial with a single exception Riccia fluitans which is aquatic.

 

Explanation:

• In Riccia fluitans (Crystalwort), the only aquatic species, the thallus is long, narrow, ribbon-like, and dichotomously branched.
• Rhizoids and scales are absent.
• This species can also grow on soil. In terrestrial species, thallus bears many rhizoids (root-like structures)
• Small, colorless, or violet scales are also present near the apex.

 

   

 

Additional Information

• R. Gangetica and R. Discolor are terrestrial species that are endemic to India (i.e.limited to Indian territory only).

Explanation: 

• Bacteria can be categorized into 4 different types based on the number of flagellum present.

1. Monotrichous – A single flagellum is present on the pole. Eg  -: Vibrio cholerae
2. Amphitrichous – Single flagellum present on both sides. Eg - Alkaligens faecalis
3. Peritrichous – Entire body of the bacteria is covered with flagella. Eg –  Salmonella Typhi
4. Lophotricous – Tuft (bunch) of flagella present on one side. Eg – Spirillum.

 

 

Cephalotrichous are bacteria with a tuft of flagella at both ends.

 

Additional Information

• The flagellum is mainly divided into three parts:

      1. Filament: It lies external to the cell surface

      2. Hook: It is embedded or fit in the cell envelope.

      3. Basal body:  It is composed of a central rod inserted into a series of rings which is attached to the cytoplasmic membrane and cell wall.

Concept:

• Hydra belongs to the phylum Coelenterata or cnidaria.
• Their name cnidarian is based on the presence of specialized structures called Cnidoblast or Cnidocyte (stinging cells)
• These cnidocytes contain stinging capsule called Nematocyst, which are present on the tentacles and body.
• These cells are used for anchorage, defence and the capture of Prey.
• The Nematocyst capsule is filled with a poisonous fluid called Hypnotoxin.

 

Explanation:

• The Hypnotoxin present in Nematocytes is injected with the help of the threaded tube.
• This thread tube acts like a piercing needle.
• The lower end of the tube is enlarged to form butt which bears spines in some cnidoblasts.

 

      

Additional Information

• When malarial parasites, sporozoites attack the RBCs of blood, it gets ruptured and a toxin is released called haemozoin, which is responsible for the high recurring fever, chills and shivering.
• Haematin is a dark bluish- brown colour pigment obtained by the oxidation of heme.
• Antigens on the surfaces of red blood cells (RBCs) are called agglutinogens and the antibodies that react against them called agglutinins.

Concept: 

• Loss of water in the form of vapours, from the aerial parts (organs) of living plants, is known as Transpiration.
• Only a few percent (1-2%) of the absorbed water is used by the plants, while the rest (98-99%) of water is lost in the atmosphere.
• ‘’Transpiration is a necessary evil’’ given by – Curtis
• ‘’Transpiration is an unavoidable evil’’ given bt – Stewart.

 

Explanation:

• Transpiration is of 3 types-
• Stomatal transpiration: Occurs through stomata, about 80-90% transpiration occurs by stomata.
• Cuticular transpiration: loss of water through the cuticle of herbaceous stems and leaves. The cuticle is the waxy layer present on the epidermis. About 9% of transpiration occurs through it.
• Lenticular transpiration: Occurs through lenticels(minute pores on stem and epidermis of woody plants). The least amount of about 0.1 to 1% transpiration occurs through it.

 

   

 

Important Points

• Minimum transpiration is found in succulent xerophytes.
• Maximum transpiration occurs in mesophytes.

 

Additional Information

• Guttation is the process of loss of water in the form of droplets from the leaf margins. It occurs when transpiration is low and water absorption is high.
• Excretion is the process of removal of nitrogenous waste material from the body.

Explanation:

• White rust disease is caused by a fungus called Albugo candida or Cystopus candidus.
• Albugo Candida belongs to the class Phycomycetes (group oomycetes) of Fungi.
• This disease mainly affects the members of the Cruciferae family-like Mustard, Cress, Rape, Radish, Cabbage, Cauliflower, turnip, etc

Symptoms of the disease are:

• It affects the aerial plant's parts like leaves and stems, roots remain unaffected
• It causes two types of infection

1. Local infection: isolated spots or pustules appear on the stem and upper leaf surface which later combine or merge to form patches.
2. Systemic infection: this infects the young stem and inflorescence of plants, which results in various types of deformities like Hypertrophy, due to which distortion and swelling are seen.
3. Oospores produced by the fungus are the main cause of this disease
4. Infection is generally favoured by a cool (13-18^o C) environment.

 

Additional Information

• Ascobolus is a coprophilous fungus i.e. it loves to grow on dung.
• Rhizopus also called bread mould belongs to the class Zygomycetes. They prefer to grow on bread.
• Puccinia is a fungi genus that lives as an obligate parasite on plants, these are called rusts. The most common rust in wheat is leaf rust caused by Puccinia tritica.

Concept:

• Gastrulation is the stage of embryonic development in which Blastula (single-layered) is differentiated into multiple layered gastrulae.
• In gastrulation, the rate of cleavage division slows down and ultimately stops at the end of gastrula formation.
• It is the most important stage in embryonic development because two main events take place during this stage.

1. DIfferentiation of blastomere into the three germinal layers - The Ectoderm, Endoderm, and Mesoderm.
2. Morphogenetic movements: During this stage, the blastomeres perform amoeboid movement and reach their definite place in the embryo.

 

Explanation:

• There are two basic methods of gastrulation:

1. Epiboly: Movement of the blastomere that forms the Ectoderm
2. Emboly: Movement of the blastomere that forms the Mesoderm and Endoderm.

• In frogs, gastrulation is performed by both epiboly and emboly.

​

Important Points

• Embryo consumes maximum oxygen during the gastrula stage because of the respiratory activity of the embryo increases.

Additional Information

• Delamination is one of the methods by which the various blasto dermic layers of the ovum are differentiated.

Concept:

• Gestation (pregnancy) can be defined as the time duration between conception and birth (delivery) of the foetus.
• It includes the development of the embryo in the uterus.
• The duration of the gestation period is variable in different species.

Explanation:

• The gestation period of a Rabbit lies between 28 - 32 days.
• The different gestation period of animals are as follows:

Important Points

The gestation period of Humans has a mean of 266 days and a standard deviation of 16 days.

Concept:

• Oedogonium is a green alga found in freshwater, it has a filamentous body.
• The cells of the filament are cylindrical except for the basal cells (holdfast) which are root-like.
• These cells are used to attach to a surface.
• Oedogonium either remains attached to other plants or is free-floating.

 

Explanation:

• These are the following stages in the cell division of Oedogonium :

1. ​The Large central vacuole disappears and the nucleus starts to move towards the centre, at a distance 2/3rd from the periphery.
2. A thick cellulosic ring appears on the lateral wall just below the distal septum, which gradually increases in thickness and forms a groove.
3. During the meantime, the nucleus divide and a floating septum forms between the two daughter nuclei.
4. The outer wall layers in the region of the cellulosic ring break transversely.
5. The cellulosic ring starts stretching longitudinally, so the cell becomes double of its original length.
6. The floating septum starts moving upwards and gets fixed at the lower end of the ruptured wall.
7. Outer two layers are resynthesized around the freshly formed cell.
8. The upper broken portion remains attached in the form of a cap, thus the newly formed cell becomes a cap cell.

     

Important Points

All the cells of Oedogonium are capable of division except the basal cell.

Explanation:

• Equisetum (Pipe) also called as ''horse tail'' is included in the class sphenopsida.
• The plant body is differentiated into root, stem and leaves. Roots are adventitious.
• Their stem is jointed i.e. their stem is divided into nodes and internodes. Scaly leaves are also present on these nodes.

Important Points

• Silica is present in the epidermis of stems and leaves in Equisetum (sphenopsida). Due to the silicated surface leaves become rough and if two plants collide, then there is a chance of dangerous fire in the forest.

Additional Information 

• Lycopodium and selaginella both belong to the class lycopsida. The plant body is differentiated into roots, stems, and leaves but the stem is not divided into nodes and internodes.
• Selaginella or spike moss are called resurrection plants because most of the species of selaginella are drought escapers i.e. do not face drought condition, complete their life cycle in the short wet season

Concept:

• Cloaca is derived from the Latin word ''sewer''.
• Cloaca represents the common chamber were intestinal, urinal and genital tracts open together, and all the material is discharged out through the cloacal aperture.
• It is found in vertebrates like amphibians, reptiles, birds, etc.
• It is absent in placental mammals and most of the members of Osteichthyes (bony fishes).

Explanation:

• The Cloaca of Uromastix or commonly called spiny-tailed lizard is divided into three parts:

1. Coprodaeum
2. Urodaeum
3. Proctodaeum

• The rectum opens into the anterior chamber Coprodaeum.
• Gonoducts and a pair of ureters open into the middle chamber Urodaeum dorsally.
• The posterior chamber proctodaeum opens externally by the cloacal aperture.

    

Important Points

• The cloaca helps in the conservation of water by reabsorbing it from the urine and faeces, thus it serves as an adaptation to survive in the arid conditions.

Concept:

• Gymnosperms are mainly classified into two groups:

1. Cycadophyta (Lower gymnosperm)
2. **Coniferophyta (Higher gymnosperm)**​

Explanation: 

• Sago grains are obtained from sago cycad, Cycas revoluta.
• It is also known by the name ''sago palm'' or ''king sago palm'', however, it is not a palm, these are just the misnomers (inappropriate name).
• It belongs to the group Cycadophyta of gymnosperms.
• It is extracted from the pith region of the stem, roots, and the seed of cycads.
• Sago grains contain starch which is often used as food.

Additional Information

• Pinus is a coniferous higher gymnosperm from the group Coniferophyta. These are large trees having ''pyramidal'' or ''excurrent shape'' just like a Christmas tree.
• Ferns form the largest group of pteridophytes called Pteropsida.
• Mosses or Bryopsida belongs to the group Bryophyta.

Concept:

• Both Taenia saginata and Taenia solium belong to the class Cestoda of phylum Platyhelminthes.
• These are Endo-Parasite of Intestines.
• They are commonly referred to as Tapeworms.
• Taenia solium - Pork tapeworm
• Taenia saginata - Beef tapeworm

Explanation:

• A Rostellum is a knob-like projection present at the anterior end of a tapeworm, as an extension. It is a globular (Round), spiny structure when it projects out, and becomes a circular hollow pit when retracted (taken back). It is structurally composed of a number of concentric rows of hooks.
• The Scolex (Head) region of Taenia solium consists of four large suckers and a rostellum containing two rows of large and small hooks.
• The Scolex of Taenia saginata has four large suckers but lacks rostellum and rostellar hooks.

​

​       

Additional Information

• Scolex represents the Head in tapeworm.
• Suckers: Organs present at the Head region of Tapeworms used for clinging to surfaces

Explanation:

• Enterobius or Oxyuruis belongs to the phylum Aschelminthes or Nemanthelminthes.
• It is also known by the name Pin-worm or Seat-worm.
• These are common parasites of Human large intestines, especially they are found in children.
• Male pinworms are about 2 to 5 mm long while the females range in length from 8 to 13 mm.

                                  A pInworm

Additional Information

• Ancylostoma also called Hookworm, belongs to the same phylum Ascheminthes, found in the small intestine.
• Ascaris also called Intestinal Roundworm is a parasite of the small intestine, Larva - Rhabditiform.
• Dracunculus also called Guinea worm (Madina worm)

Concept:

• Angiosperms are divided into various families, Leguminosae is one of them.

Systematic position:

Class - Dictoledonae

Sub class - Polypetalae

Series - Calyciforae

Order - Rosales

Family - Leguminosae

Explanation:

• This family is economically important because it includes pulses and some medicinal plants which are used as food and healing material.
• Members of this family include Pulses like Pea, Gram (Chana), French bean (Rajma), Green gram (Moong).
• Fodder: Dhaincha (Sesbania), Medicinal plants like Mulaithi.
• Other important characters of this family are:

1. ​Roots: Roots are branched and a tap root system is present. In roots N₂ fixing bacteria Rhizobium is present.
2. Stem: Erect or climber
3. Leaves: Stipulate, simple, or compound-unipinnate.
4. Inflorescence: Typical raceme (Racemose)

Additional Information

• Poaceae or Gramineae family includes Cereals.
• Lamiaceae family has essential oils.

Concept-

Microbes belong to diverse organisms – bacteria, fungi, protozoa, viruses.

Microbes influence man's life in several ways- they are found in clothes, jams, shoes, dead wood, food products, soil, etc.

• Yeast- it is used as a fermentation agent in the bakery (bread industry) and brewery (wine industry). So, Saccharomyces cerevisiae is also called “Baker’s yeast”.
• Agaricus- it is called “gill fungi” because gills like pores are present in its fruiting body. It is also called fairy rings because its fruiting body looks like rings.
• Mucor- it is called bread mold. It grows on bread. The tip of the mycelium is black colored. Therefore, this fungus looks black colored.
• Pythium- Causes “Damping-off’’ disease in tobacco and “vegetable crops”.

Explanation-

• Bread is made from grain usually wheat.
• The selected strain of yeast (Saccharomyces cerevisiae) grown on molasses are used as Baker’s yeast.
• Yeast is added to wheat flour. And is kneaded. The kneaded flour is kept at a warm temperature until it swells up. The phenomenon is called leavening.
• The process of leavening is done by secretion of 3 enzymes by yeast-
• Amylase causes a breakdown.
• Maltase convert maltose into glucose.
• Glucose is acted upon by zymase.
• Zymase is a complex of several enzymes of anaerobic respiration which brings about fermentation.
• Fermentation of glucose mainly forms ethyl alcohol and carbon dioxide. It leaves the dough.
• The leavened dough is baked. Both carbon dioxide and ethyl alcohol evaporate making the bread porous and soft.

Concept-

• The animal kingdom is a kingdom of multicellular eukaryotic animals.
• An animal kingdom divided into invertebrates and vertebrates.
• The name vertebrate is derived due to the presence of serially arranged vertebrae in the backbone of vertebrate animals.
• Classification of Vertebrata on the basis of jaws.

           

• Pisces is the first true jawed vertebrate group.
• Pisces has three classes-

1. Placodermi- Example- Climatius
2. Chondrichthyes- they are called cartilaginous fishes. So, the endoskeleton is entirely cartilaginous. Example**-Scoliodon**, Trygon, etc.
3. Osteichthyes- they are called bony fishes. So, endoskeleton of bone. Example- Salmo, gambusia, etc.

Explanation-

• Hence, it is concluded from the above explanation that an endoskeleton is a skeleton found within the interior of the body of the animals.
• It provides structural support and protection for the internal organs and tissues of an organism.

Endoskeleton of scoliodon made up of cartilage.

Additional Information

• Scoliodon is included in members of shark fish. Scoliodon also called Dogfish because they have a dog-like sense of smell.

Concept-

• The Human neural system is divided into two parts-
• Central neural system – consists of the brain and the spinal cord and is the site of information processing and control.
• Peripheral neural system- the nerve arising from the CNS, constitute the PNS.
• The nerve fibres of the PNS are of two type-
• Afferent fibres (Sensory)- Conducts impulses from receptors to the CNS.
• Efferent fibres (Motor)- Conducts impulses from CNS to effectors (muscles and glands).
• The PNS is divided into two divisions-
• Somatic neural system (SNS)- controls and coordinate those organs which are under voluntary control.
• Autonomic neural system (ANS)- controls and coordinate those organs which are under involuntary control.

 

Explanation-

• The autonomic neural system or visceral nervous system is the part of the peripheral nervous system.
• It comprises the whole complex of nerves, fibres ganglia by which impulses travel from the CNS to the viscera(internal organs) and from the viscera to the CNS.
• Its controls activities inside the body that are involuntary such as heartbeats or your digestive system digest without your conscious control.

Concept-

Industrial waste often contains a specific poison that is either dangerous to health or kills the bacteria that help in decomposition.

Some of the industrial wastes are-

Explanation-

• Itai-Itai is first reported in Toyoma city of japan as a mass cadmium poisoning.
• Cadmium is a heavy metal introduced into the environment (water) through the industry's discharge. Then through fish or as water introduced into the human body.
• Due to the same oxidation number as Zn²⁺. It interferes with many biological reactions in enzymes and replaces Zn²⁺ with Ca²⁺.
• Cadmium affects the human body by increasing blood pressure, kidney damage, bone narrow disorder. But mostly result in severe kidney damage and osteomalacia.
• Osteo means bone and malacia means softness. In Japan, ouch-ouch refers to bone pain.
• Itai-Itai also called ouch-ouch disease.

Concept-

• A Eukaryotic cell is composed of nucleus, cytoplasm, and cell boundaries (cell wall, cell membrane).
• The cytoplasm is a viscous fluid where various chemical reactions occur.
• In both plant and animal cells, cytoplasm has membrane-bound structures called organelles like the endoplasmic reticulum (ER), the Golgi complex, lysosomes, mitochondria, peroxisome.
• The non-membrane bound structure called organelles like ribosomes.

Explanation-

• In most of the plant cells and invertebrates, the small Golgi complexes are found scattered in the cytoplasm along with the parts of ER are called dictyosomes.

Additional Information

• Ribosomes- are also called “Organelle within an organelle’’ and the “Protein factory of the cell”.
• Peroxisome- are also called Microbody.
• Lysosomes- are also called Suicidal bags.
• Golgi bodies- are also called dictyosomes.

Concept-

• Viruses did not find a place in classification since they are not considered truly ‘living’.
• Viruses are non-cellular organisms.
• The name virus that means venom or poisonous fluid was given by Dmitri Ivanowsky.
• Viruses cause diseases like mumps, smallpox, herpes, and influenza.

Explanation-

• Viruses are mainly composed of nucleic acid and protein.
• Nucleic acids consist of DNA and RNA.
• The nucleic acid that is the double or single-stranded DNA or RNA forms the genetic makeup of the virus.
• Genetic material is infectious.

Therefore the material that enters the host cell is only nucleic acid.

Additional Information

• The protein coat called capsid made of small subunits called capsomeres protects the nucleic acid.
• Protein and Nucleic acid together called the nucleocapsid.
• Viruses could be crystallized and crystals consist largely of proteins. They are inert outside their specific host cell.

Concept-

• Five Kingdom Classification was proposed by R.H. Whittaker. Five kingdoms defined in this classification were named Monera, Protista, Fungi, Plantae, and Animalia.
• Fungi are heterotrophic eukaryotes that are usually filamentous, devoid of chlorophyll, with the chitinous cell wall, and produces spores.
• Fungi show a great diversity in morphology and habitat.
• Fungi are cosmopolitan and occur in air, water, soil, and animals and plants.

Explanation-

• Agaricus is an edible fungus.
• Agaricus is commonly known as Mushroom.
• Mushrooms contain protein, vitamins, minerals, and antioxidants.
• It is a fleshy, spore-bearing body of fungus which is used as food material by humans.
• It belongs to the class Basidiomycetes and it is scientifically known as Agaricus.

Additional Information

• White rust of crucifers is caused by a fungus called Albugo candida.
• Pythium causes “Damping-off’’ disease in tobacco and “vegetable crops”.

Explanation-

The smallest proteinaceous infectious particle is known as prions.

• Prions are infectious particle which is made up of only protein.
• Prions were named by Stanley Prusiner.
• The most notable diseases caused by prions are bovine spongiform encephalopathy (BSE) commonly called mad cow disease in cattle and its analogous variant Cr–Jacob disease (CJD) in humans.

Additional Information

• Viroids -
• Simple infectious agents consist of ss- RNA.
• Discovered by T.O. Diener.
• Caused potato spindle tuber disease.
• Virus-
• The viruses are non-cellular organisms that are characterized by having an inert crystalline structure outside the living cell.
• The name virus that means venom or poisonous fluid was given by Dmitri Ivanowsky.
• Viruses cause diseases like mumps, smallpox, herpes, and influenza.
• Bacteriophage-
• The virus which infects the bacteria is called bacteriophage.
• A bacteriophage is generally a double-stranded DNA virus.
• In QB - bacteriophage - ss RNA is present.
• In ϕ X 174 - bacteriophage - ss DNA is present.

Mistake Points

• The name Fungia should not be confused with "Fungi" as both are different.
• Fungia is an animal that looks like mushroom and hence the name.

Key Points

• Corals are a group of marine invertebrates that form colorful colonies or individual polyps.
• These polyps form the coral-reefs from their hardened exoskeletons.
• Corals are important for the tropical ecosystems as they protect the shorelines from tropical storms, erosion and damaging wave actions.
• They also provide shelter and habitat for many marine organisms.​

Important Points

• Fungia is a genus of corals that belong to the phylum Cnidaria in Animalia kingdom.
• Habit & Habitat - It is usually solitary and is a marine coral that is found in warmer seas.
• Morphology -
• Its size may vary from 5 mm to 25 cm in diameter.
• It has a discoidal mushroom-shaped body.
• It has numerous septa connected together by synapticula.
• Adult animal contains a single large polyp with tentacles.
• It may lie loosely on the coral reef slopes or attached below by a stalk.
• It is a stony coral with a calcareous exoskeleton.

Additional Information

• Red coral -
• It is the common name for the genus Corallium.
• It is also known as precious coral as it is used for jewelry-making.
• They have intense red-colored polyps.
• Brain coral -
• It refers to coral members of the families Mussidae and Merulinidae.
• It has an oblong shape with grooved surfaces that resembles a human brain.
• Organ pipe coral -
• It is the common name for the coral Tubipora musica.
• They have long, upright polyps supported by calcareous skeleton.
• When the soft parts die, the skeleton remains as colorful tubes that resemble organ pipes.

Concept-

• Plastids are found in plants and euglenoids.
• Based on the type of pigments plastids can be classified into chloroplasts, chromoplasts, and leucoplasts.
• The chloroplasts contain chlorophyll and carotenoid pigments which are responsible for trapping light energy essential for photosynthesis.
• The chloroplasts are double membrane-bound.
• The majority of the chloroplasts of the green plants are found in the mesophyll cells of the leaves.

Explanation-

• The chloroplast is lens-shaped, oval, discoid,cup-shaped, girdle shaped, reticulate, plate-like, ribbon-shaped, or spiral.
• Chlamydomonas is unicellular green algae.
• The shape of Chlamydomonas chloroplast is cup-shaped.

Additional Information

Concept-

• Kingdom Animalia is divided into sub-groups which is known as Phylum. There are 11 phyla in the kingdom Animalia.
• Porifera, Coelenterata, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata.
• Mammals are the class of phylum Chordata.
• A unique characteristic of mammals is the presence of milk-producing glands**(mammary glands).**
• The mammals are unique in possessing hair.

Explanation-

• Eutherian are true mammals.
• Uterus and vagina and penis are single.
• Nipples are well marked.
• Eutherian are viviparous i.e. they give birth to a mature child.

Additional Information

• Homo sapiens are eutherian.
• Prototherians are oviparous mammals i.e. they lay an egg.
• Metatherians are ovoviviparous mammals.

Concept:

• Roots are the underground structures that help in the absorption of water and minerals, provide a proper anchorage to the plant parts, storage of reserve food material ( Radish), and synthesis of plant growth regulators.
• Sometimes roots get modified to perform different functions like Storage of food, respiration, climbing, etc. These types of roots are called modified roots.
• Examples - Pneumatophores of Rhizophora, and Mangrove plants for respiration.

Explanation:

• In marshy/swampy areas, scarcity of oxygen is found.
• Some branches of taproot of the plants which grow in this region, grow vertically upward (negatively geotropic) and comes to the surface.
• These roots are called pneumatophores with having minute pores called pneumathodes or lenticels by which air enters the plant and the plant gets oxygen for respiration.

Additional Information

Concept-

• The frog's most common species is Rana tigrina.
• Frog has the ability to change their color to hide from their enemies (camouflage).
• The frog never drinks water but absorbs it through the skin.
• Frogs also go into hibernation (winter sleep) and aestivation (summer sleep).
• Frogs are cold-blooded ( their body temperature varies with the temperature).
• The frog body is divided into two parts- Head and trunk.

Explanation-

• The nervous system is divided into 3 parts-
• (1) Central nervous system (2) Peripheral nervous system (3) Autonomous nervous system
• The peripheral nervous system is made up of cranial nerves and spinal nerves.

10 pairs of cranial nerves are present in frogs i.e. 20 cranial nerves.

Additional Information

• 10 pairs of spinal nerves are present in frogs.
• 10 vertebrae are present in the frog.
• Sexual dimorphism is present in frogs.
• Frogs are beneficial for mankind because they eat insects and protect the crop.

Concept-

• In the five-kingdom classification of Whittaker, there is no mention of viruses.
• The virus means poisonous fluid or venom or secretion.
• Viruses are submicroscopic and non-cellular organisms.

Explanation-

• The virus which infects the bacteria is called bacteriophage.
• A bacteriophage is generally a double-stranded DNA virus.
• In QB - bacteriophage - ss RNA is present.
• In ϕ X 174 - bacteriophage - ss DNA is present.
• A bacteriophage is of two types- Non-infective phages and infective phage.

Additional Information

• Viruses are of different types based on host-
• Phytophages (Plant viruses)- viruses infect the plants.
• Zoophages (Animal viruses)- viruses infect the animals.
• Bacteriophages- viruses infect bacteria.
• Cyanophages- viruses infect blue-green-algae.
• Zymophages- viruses infect yeasts.

Concept-

• Plants are divided into five groups- Thallophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.
• They are the first terrestrial plants to acquire vascular tissues – xylem and phloem.
• Pteridophytes have two groups-
• The majority of the pteridophytes are homosporous eg. Psilotum, Adiantum, and Equisetum.
• While some pteridophytes are exceptionally heterosporous eg. Selaginella, Azolla, Salvia, and Marsilea.

Explanation-

• The endodermis (the innermost layer of the cortex adjacent to the pericycle) is composed of closely packed cells that have within their walls Casparian strips, water-impermeable deposits of suberin that regulate water and mineral uptake by the roots.

The endodermis in Selaginella is interrupted by large intercellular spaces except in xerophytic species. This is called the trabeculated endodermis.

 

Additional Information

• Lycopodium- It is a plant of a genus that includes the common clubmosses. The plants are mainly native to tropical mountains but are also common in northern forests of both hemispheres.
• Equisetum- Equisetum (Equisetaceae) is herbaceous and homosporous. It has very small leaves that are more or less fused to form a dentiform leaf sheath at the node. The surface of the internodes shows distinct longitudinal ridges from the vascular bundles, Equisetum predominately occurs in wet environments, and the hollow stems, characteristic also of many extinct sphenopsids, indicate that it was adapted to growth in moist areas.
• Marsilia- The plants are herbaceous with rhizomatous stem, creeping on or just below the soil surface. The species of Marsilea are generally aqua­tic or amphibious in nature with their roots embedded in mud or damp soil.

Concept-

• Malaria is caused due to Protozoa Plasmodium vivax.
• It is transmitted through the female anopheles mosquito.
• The protozoan plasmodium mainly attacks red blood cells (also called erythrocytes), the liver, and the spleen of the human body.

Explanation-

• Schuffner's dots observered in malaria.
• The bright yellow-colored granules that appear in the cytoplasm of RBC are called Schuffner's dots.
• Schuffner's dots are assumed to be the waste product of plasmodium.
• These dots are used to diagnose malaria because they are the clearest structures that appear in the blood.
• Schuffner's dots are observed with the use of romanovaski stain.

Additional Information

• 29th August is Malaria day.
• Plasmodium is a member of the Sporozoa class.
• Kala-azar is also called black fever.
• Wuchereria(filarial worm) causes filariasis or elephantiasis.

Concept-

• Kingdom plants are divided into five groups- Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.
• Angiosperms are divided into various families.
• Gramineae is one of them.
• Systematic position:
• Class -Monocotyledonae
• Series -Glumaceae
• Family -Gramineae or Poaceae

Explanation-

• Gramineae is the largest family of the Indian flora.
• Examples of Gramineae-
• Zea mays- Maize
• Triticum Vulgare- Wheat

Additional Information

Concept-

• Bacteria are the sole members of the Kingdom Monera.
• Blue-green algae come under Kingdom Monera.
• Blue-green algae are also known as cyanobacteria.
• Blue-green algae are photosynthetic autotrophs.

Explanation-

• Some of the Blue-green algae can perform Nitrogen fixation.
• Blue-green algae fix nitrogen through specialized cells called heterocysts.
• They convert atmosphere nitrogen into nitrogenous compounds like amino acids, nitrates. These nitrates increase the fertility of the soil.
• Hence blue-green algae improve the fertility of the soil by nitrogen fixation.

Examples of blue-green algae that fix nitrogen are Nostoc.

Important Points

• Cyanobacteria were the first organisms that produced oxygen on our earth.

Additional Information

• Brown algae, green algae, and red algae are the algae that come under Kingdom Plantae.
• Member of Chlorophyceae is commonly known as 'green algae'.
• Member of Phaeophyceae is commonly known as 'brown algae'.
• Member of Rhodophyceae is commonly known as 'red algae'.

Concept-

• The study of birds is called ornithology.
• All the types of birds are included in the class Aves.
• Birds are warm-blooded or Homeothermic i.e body temperature remains almost constant.

Explanation-

• Eyes are very sharp.
• Eyes have pecten which is a comb-like structure inside the vitreous humor.
• Pecten helps in the fitting of the eye and provides nutrition to eyeballs.
• It also regulates the pressure of liquid present in the eye.
• Due to pecten birds have acute vision and telescopic vision.

Pecten is found in the eyes of all birds except kiwi's eyes.

Additional Information

• Peacock is the national bird of India.
• The scientific name of the pigeon is Columba livia.
• The scientific name of the crow is Corvus splendens.

Explanation-

• Lichen is the symbiotic association of fungi and algae.
• The algal component is known as phycobiont.
• The fungal component is known as mycobiont.
• The algae prepare food for fungi i.e. algae are autotrophic.
• The fungi provide shelter and absorb mineral nutrients and water for their partner i.e. fungi are heterotrophic.

Additional Information

• Lichens are very good pollution indicators.
• Lichen is an example of Mutualism.
• The association of fungi with roots of higher plants known as mycorrhiza.

Concept-

• The unit of the female reproductive organ is the pistil or carpel.
• The carpel has three regions- Stigma, Style, and Ovary. An ovary contains an ovule.
• There are six different types of ovules in Angiosperms on the basis of the position of different parts.

1. Orthotropous 2. Anatropous 3. Hemitropous 4. Amphitropous 5. Campylotropous 6. Circinotropous

Explanation-

• The body of the ovule in the orthotropous is upright.
• The chalaza, micropyle, and hilum lie in one straight line.
• This is the most primitive ovule.

The ovule in which micropyle lies at one end while chalaza and hilum lie at the opposite end is called an orthotropous ovule.

Note- One can easily get the answer to this question by looking at the diagram given above.

Additional Information

• Most common type of ovule is Anatropous ovule.

Concept-

• The transformation of the larva into an adult through drastic changes is called metamorphosis.
• Metamorphosis is a biological process that involves sudden and abrupt changes in the body structure of the animal by cell growth and differentiation.
• Metamorphosis is generally observed in amphibians and insects.
• Insects are divided into four groups based on their development-
• Ametabolous development- insects without metamorphosis.
• Paurometabolous development- insects with gradual metamorphosis.
• Hemimetabolous development- insects with incomplete metamorphosis.
• Holometabolous development- insects with complete metamorphosis.

Explanation-

• Metamorphosis in insects initiated internally by hormones.
• Ecdysone hormone is secreted by the prothoracic gland.

Metamorphosis is promoted by ecdysone hormone.

Additional Information

• Hormones are organic substances.
• Thyroxine is an iodine-containing amino acid secreted by the thyroid gland.
• Pherohormone used by most insects to communicate.

Concept:

• Algae can be classified on the basis of pigments present in them.
• Chlorophyceae – green algae
• Phaeophyceae – brown algae
• Rhodophyceae – red algae

Explanation:

• The dwarf male is a small plant of algae of the family Oedogoniaceae that consists of a few cells, develop from an androspore near the oogonium, is usually attached to the cell below it, and produces only spermatozoids.
• It is an example of green algae.
• Most advanced algae is green algae.

Important Points 

• Oedogonium is a green alga found in freshwater, it has a filamentous body.
• The cells of the filament are cylindrical except for the basal cells (holdfast) which are root-like.
• These cells are used to attach to a surface.
• Oedogonium either remains attached to other plants or is free-floating.

Additional Information

• These are the following stages in the cell division of Oedogonium :
• The Large central vacuole disappears and the nucleus starts to move towards the centre, at a distance 2/3rd from the periphery.
• A thick cellulosic ring appears on the lateral wall just below the distal septum, which gradually increases in thickness and forms a groove.
• During the meantime, the nucleus divide and a floating septum forms between the two daughter nuclei.
• The outer wall layers in the region of the cellulosic ring break transversely.
• The cellulosic ring starts stretching longitudinally, so the cell becomes double of its original length.
• The floating septum starts moving upwards and gets fixed at the lower end of the ruptured wall.
• Outer two layers are resynthesized around the freshly formed cell.
• The upper broken portion remains attached in the form of a cap, thus the newly formed cell becomes a cap cell.

Concept-

• Kingdom Animalia is divided into sub-groups which is known as Phylum. There are 11 phyla in the kingdom Animalia.
• Porifera, Coelenterata, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata.
• Pila is the example of the kingdom Mollusca.
• Mollusca is the second largest phylum that includes "soft bodies and shelled"animals.
• In Mollusca development is mostly indirect i.e. embryo directly convert into an adult without larva stage.

Explanation-

• Pila is dioecious i.e. male and female are separate.
• Females are larger than males.
• The male reproductive system consists of the testis, vas deferens, and penis.
• In pila two types of sperms are found- Eupyrene and oligopyrene sperms.
• Eupyrene sperm- They have a head, middle piece, and tail because of the tail, they can swim. And fertilize the ovum.

Therefore eupyrene is the motile sperms of pila i.e. it can move.

Additional Information

• Oligopyrene sperms are also the sperm of pila but they are non-motile sperm i.e. they cannot move and can never fertilize.
• The larva of pila is veliger.
• The common name of pila is apple snail.

Concept-

• Fossils are the impressions of hard parts of the organisms in the strata of the earth.
• Types of fossils are-
• Unaltered fossils- Whole body of extinct organisms is found.
• Petrified fossils- These fossils consist of only hard parts.
• Mold fossils- Only the impression of external structure.
• Cast fossils- Minerals fills in the mold.
• Print fossils- Prints made in soft mud.
• Coprolites- Fossil preservation of contents of the intestine or excreta.

Explanation-

• Pollen grain outer layer is called exine.
• The exine is made up of sporopollenin which is one of the most resistant organic materials known.
• Sporopollenin can withstand high temperatures and strong acids and alkali.
• No enzymes that degrade sporopollenin is so far known.

Pollen grains are well preserved as fossils because of the presence of sporopollenin.

Additional Information

• The study of fossils is known as Palaeontology.
• The study of fossils indicates the time in which they existed.

Concept:

• The cell is the basic unit of life. Cells grow and multiply to form a diversity of life forms, this process of growth and multiplication of cells is called Cell Division.
• Cell division is of three types:
• Mitosis - Equational division.
• Meiosis - Reductional division, occurs in sex cells
• Amitosis - Direct type of division, occurs in prokaryotes

Explanation-

• Meiosis can be further divided into two stages - Meiosis I and Meiosis II
• Prophase I of Meiosis I has 5 sub-stages.
• Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis.
• The Pachytene stage is characterized by the occurrence of crossing over.
• Non-sister chromatids of the homologous chromosomes exchange their genetic parts.

Thereby Crossing over occurs in the pachytene of Prophase I.

Additional Information

• Stages of Meiosis-

Concept-

• The animal kingdom is a kingdom of multicellular eukaryotic animals.
• An animal kingdom divided into invertebrates and vertebrates.
• The name vertebrate is derived due to the presence of serially arranged vertebrae in the backbone of vertebrate animals.

• Classes of vertebrates are-
• Fish- Ex- whales.
• Amphibians- Ex- frogs.
• Reptiles- Ex- lizards.
• Birds- Ex- pigeons.
• Mammals- Ex- whales.

Explanation-

• Pneumatic bone is an important characteristic of Aves (Bird).
• Present throughout the body of birds, pneumatic bones are hollow bones filled with air cells.
• This makes the skeleton light thereby enabling the birds to fly.
• An example of Aves is pigeons.

Additional Information

• The study of birds is known as ''Ornithology''.
• All the birds are included in class Aves.

Concept-

• Kingdom plants are divided into five groups- Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.
• The Algae body is relatively undifferentiated. Like true roots, stems, and leaves are absent.
• Algae are unicellular, motile, non-motile, filamentous, colonial, and other forms.
• Algae is divided into the following classes-
• Chlorophyceae (green algae)- The pigment of green algae is chlorophyll a and b.
• Phaeophyceae (brown algae)- The pigment of brown algae is chlorophyll a, c and fucoxanthin.
• Rhodophyceae (red algae)- The pigment of red algae is chlorophyll a, d and phycoerythrin.

Explanation-

• Some green algae are present in the colonial form.
• They form the colony of cells and the number of cells is fixed in the colony.
• An example of colony form in green algae is volvox.

Additional Information

• An example of the unicellular form of green algae is Chlorella, Chlamydomonas.
• An example of the filamentous form of green algae is Spirogyra and Ulothrix.
• An example of the parenchymatous form of green algae is Ulva (sea lettuce).

Concept:

• Five Kingdom Classification was proposed by R.H. Whittaker. Five kingdoms defined in this classification were named Monera, Protista, Fungi, Plantae, and Animalia.
• Fungi constitute a unique kingdom of heterotrophic organisms.
• Fungi show a great diversity in morphology and habitat.
• Fungi are cosmopolitan and occur in air, water, soil, and animals and plants.

Explanation-

• Puccinia is the fungi that cause rust disease.
• Three different species of Puccinia develop rust in wheat-
• Puccinia graminis  -  Black rust or stem rust
• Puccinia recondita -  Brown rust or leaf rust
• Puccinia striiformis - Yellow rust or stripe rust

Additional Information

Concept-

• Kingdom Animalia is divided into sub-groups which is known as Phylum. There are 11 phyla in the kingdom Animalia.
• Porifera, Coelenterata, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata.

Explanation-

• Echinodermata is the phylum of kingdom Animalia.
• Echinodermata have an endoskeleton of calcareous ossicles, so these are named Echinodermata.
• Member of Echinodermata phylum is all marine animals with the organ-system level of organization.
• Echinodermata are triploblastic.
• Echinoderms have the unique feature of the presence of a water vascular system which has the following purpose-
• Locomotion
• Capture and transport of food
• Respiration

Therefore Echinoderms have water vascular system.

Additional Information

• Unique features of different phyla- 
• Porifera- also known as spores because they have pores.The water canal system, also known as the aquiferous system, is a distinctive feature of the phylum Porifera, commonly known as sponges.
• Coelenterata- also known as cnidaria because they have cnidoblasts.
• Ctenophora- also known as sea walnuts or comb jellies. And they have comb plates.
• Platyhelminthes- also known as flatworms because they have a flat body.
• Aschelminthes- also known as roundworms because the body has a circular cross-section.
• Annelida- Body segmentation
• Arthropoda- They have joint appendages.
• Mollusca- Body covered with a calcareous shell.
• Echinodermata- Water vascular system.
• Hemichordata- The body is made up of proboscis, collar, and trunk.
• Chordata- Notochord, a dorsal hollow nerve, and paired pharyngeal gill slits.

Concept-

• Plants are divided into five groups- Thallophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.
• Pteridophytes are the first terrestrial plants to acquire vascular tissues – xylem and phloem.
• Pteridophytes have two groups-
• The majority of the pteridophytes are homosporous i.e., one type of spores formed.
• While some pteridophytes are exceptionally heterosporous.

Explanation-

• In heterosporous pteridophytes, two types of spores are formed i.e. microspore and megaspores.
• In heterosporous pteridophytes, the microspore produces male gametophyte and the megaspore produces female gametophyte.
• The development of the zygote into a young embryo takes place within the female gametophyte
• The female gametophyte is remained attached to the parent sporophyte for variable periods.

Examples of heterospory pteridophytes are Selaginella and Marsilea.

Additional Information

• Examples of homospory pteridophytes are Psilotum, Lycopodium, Equisetum etc.
• Pteridophytes are further classified into four classes-
• Lycopsida- Examples are Selaginella and Lycopodium.
• Psilopsida- Examples are Psilotum.
• Sphenopsida- Examples are Equisetum.
• Pteropsida- Examples are Dryopteris, Pteris, and Adiantum.

Concept-

• Kingdom plants are divided into five groups- Thallophytes, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.
• Thallophyta
• The plant body is not differentiated from roots, stems, and leaves.
• They are commonly called algae.
• Bryophyta
• These are small terrestrial plants.
• They show differentiation in the body design, with stem, leaf-like structures, and root-like structures.
• Pteridophyta
• The plant body is differentiated into roots, stems, and leaves, apart from having a specialized tissue for conduction.
• Gymnosperms
• Gymnosperms are plants with naked seeds.
• Angiosperms
• Angiosperms are seed-bearing plants. Seeds develop inside tissues that get modified to form the fruit of the plant.

Explanation-

• Bryophytes are small, non-vascular plants.
• The reproduction of Bryophytes is via spores.
• Bryophytes are generally classified into three coordinate phyla namely the liverworts, hornworts, and mosses.
• Bryophytes are often referred to as the amphibians of the plant kingdom. Because even though they live in the soil, they need water for sexual reproduction.

Additional Information

• The five-kingdom system proposed by R.H. Whittaker (1969).
• The main criteria for classification used by him- 
• (1) Cell structure (2) Body organization (3) Mode of nutrition (4) Reproduction (5) Phylogenetic relationships.
• The kingdom defined by him was named-
• Monera- All the prokarytotes.
• Protista- All the Unicellular eukaryotes.
• Fungi- True fungi.
• Plantae- All the multicellular plants.
• Animalia- All the multicellular animals.

Concept-

• Five Kingdom Classification was proposed by R.H. Whittaker. Five kingdoms defined in this classification were named Monera, Protista, Fungi, Plantae, and Animalia.
• All the bacteria comes under kingdom monera.

Explanation-

• Citrus canker is a disease of plants caused by the bacterium Xanthomonas citri.
• Xanthomonas is a gram-negative bacteria.
• Most of the pathogenic bacteria are from the gram-negative group.
• Xanthomonas causes damage to the plant leaves, stem, and fruit.
• The infection causes by citrus trees, including lime, oranges, and grapefruit.

Additional Information

Concept-

• Lichen is the symbiotic association of fungi and algae.
• The algal component is known as phycobiont.
• The fungal component is known as mycobiont.
• The algae prepare food for fungi i.e. algae are autotrophic.
• The fungi provide shelter and absorb mineral nutrients and water for their partner i.e. fungi are heterotrophic.

Explanation-

• Litmus is the acid-base indicator.
• Litmus is obtained from Roccella tinctoria which is the lichen.

Important Points

• Lichens are very good pollution indicators - they don't grow in polluted areas.

Additional Information

• Peltigera canina is the lichen that is used against hydrophobia.
• Cetraria islandica is the lichen that is used as a laxative.

Concept-

• The five-kingdom system proposed by R.H. Whittaker.
• The kingdom defined by him was named- Monera, Protista, Fungi, Plantae, Animalia.
• Kingdom Animalia is divided into sub-groups which is known as Phylum. There are 11 phyla in the kingdom Animalia.
• Porifera, Coelenterata, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata.

Explanation-

• Phylum Annelida main features:
• The body is long, thin, soft, and metamerically segmented.
• Locomotion takes place through Setae made up of Chitin.
• The alimentary canal is well developed.
• The nervous system is normal and blood is red.
• Excretion by nephridia.
• Both unisexual and bisexual.
• Example: Earthworm.

Therefore nephridia are the excretory gland present in Annelida.  

Additional Information

• Unique features of different phyla- 
• Porifera- also known as spores because they have pores.
• Coelenterata- also known as cnidaria because they have cnidoblasts.
• Ctenophora- also known as sea walnuts or comb jellies. And they have comb plates.
• Platyhelminthes- also known as flatworms because they have a flat body.
• Aschelminthes- also known as roundworms because the body has a circular cross-section.
• Annelida- Body segmentation
• Arthropoda- They have joint appendages.
• Mollusca- Body covered with a calcareous shell.
• Echinodermata- Water vascular system.
• Hemichordata- The body is made up of proboscis, collar, and trunk.
• Chordata- Notochord, a dorsal hollow nerve, and paired pharyngeal gill slits.

Concept-

• Pollen grains are generally spherical (Shapes may vary) structures measuring about 25-50 micrometers in diameter.
• Pollen grains have two prominent walls, the outer exine made up of sporopollenin which is referred to as one of the most resistant organic materials known.
• The inner intine layer is made of cellulose and pectin.
• The cytoplasm of pollen grains is surrounded by a plasma membrane. At maturity, pollen grains are composed of two cells.
• Vegetative cell or nucleus
• Generative cell or nucleus

Explanation-

• Pinus plant is the anemophilous plant.
• Anemophilous plants are wind-pollinated plants.
• The winged-shaped pollens can suspend in the air for a long time because of their shape.

Therefore winged pollen grain is found in pinus.

Additional Information

• The floral part that produces Pollen Grain is Anther.
• The pollen grains represent the male gametophytes.
• Pollination is the transfer of Pollen Grains from a Male part called (Anther) of a plant to a Female part called (Stigma) of a plant.
• Types of pollination-

Concept-

• The fruit is a characteristic feature of flowering plants.
• The fruit is a mature or ripened ovary, developed after fertilization.
• The pericarp is the fruit wall and may be thick and fleshy or thick and hard or thin or soft.
• The pericarp is made up of 3 layers-
• Epicarp = Outermost layer
• Mesocarp = Middle layer
• Endocarp = Innermost layer

Explanation-

• The fruit of coconut is called drupe fruit.
• The endosperm is initially suspended within the coconut water.
• But on maturation, the cellular layer of endosperm deposits along the wall.
• The water and edible parts of the coconut are liquid and solid endosperm respectively.

Thereby the edible part of the fruit of coconut is the endosperm.

Additional Information

• In coconut-
• The epicarp is hard and thin.
• The mesocarp is thick and fibrous.
• The endocarp is hard and the seed is protected in it.
• If the fruit is formed without fertilization of the ovary is called a parthenocarpic fruit.

Concept-

• A microorganism is a living thing that is too small to be seen with the naked eye.
• Microorganisms are classified into four major groups. These groups are bacteria, fungi, protozoa, and some algae.
• The effect of microorganisms in our daily lives is so much, some are beneficial for human beings but some of the microorganisms are very harmful to the living and in extreme cases may lead to death.

Explanation-

• Nitrogen-fixing bacteria and microorganisms are capable of transforming atmospheric nitrogen into fixed nitrogen.
• Nitrogen fixation is the chemical process by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle.
• Atmospheric nitrogen is fixed by several methods like biological N₂ fixation, Industrial N₂ fixation, and Electrical N₂ fixation.
• It is a necessary process, as the fixed nitrogen is used in the biosynthesis of several organic compounds like amino acids, proteins, nucleic acids, etc.
• Atmospheric nitrogen cannot be absorbed directly by the plants so it is first converted into stable compound ammonia (NH₃) in the roots, with the help of symbiotic bacteria.

N₂ → N₂H₂ → N₂H₄ → 2NH_3​

• In leguminous plants, Rhizobium bacteria helps in fixing the atmospheric nitrogen, and in Non-leguminous bacteria like Frankia fixes it.

Thereby rhizobium plays an important role in nitrogen fixation.

Additional Information

Lactobacillus-

• It is a genus of Gram-positive bacteria.
• It is the bacteria that is used to convert milk into curd.
• Conversion of milk into curd is done by the process called fermentation.
• Lactobacillus is the non-spore-forming bacteria of the family Lactobacillaceae.
• Lactobacillus bacteria have the ability to produce lactic acid as a by-product of glucose metabolism.
• Lactobacillus bacteria are commercially used during the production of sour milk, yoghurt. and cheeses.
• These bacterias can survive in both aerobic and anaerobic environments.

Pseudomonas-

• It is a type of bacteria that is found commonly in the environment.
• It is rod-shaped, a sporogenous, and mono flagellated bacterium.
• Pseudomonas infections are illnesses that are caused by the bacteria Pseudomonas.

Concept-

• Viruses did not find a place in classification since they are not considered truly ‘living’.
• Viruses are non-cellular organisms.
• The name virus that means venom or poisonous fluid was given by Dmitri Ivanowsky.
• Viruses cause diseases like mumps, smallpox, herpes, and influenza.

Explanation-

• Viruses are mainly composed of nucleic acid and protein.
• The protein coat called capsid made of small subunits called capsomeres protects the nucleic acid.

Thereby the correct statement is virus protein coat is made up of capsomere.

Additional Information

• The virus is made up of protein and nucleic acid.
• Viruses can multiply in living cells only because they take over the machinery of the host cell to replicate themselves.
• Viruses could be crystallized and crystals consist largely of proteins. They are inert outside their specific host cell.

Explanation-

• Blue-green algae(BGA) are actually types of bacteria known as Cyanobacteria.
• BGA is widely distributed all over the earth.
• Some of the blue-green algae can perform nitrogen fixation. They convert atmospheric nitrogen into nitrogenous compounds like amino acids, nitrates.
• Nitrogen-fixing BGA, including free-living and symbiotic forms.
• An example of a symbiotic form is in the coralloid roots of cycas.

Thereby Algal symbiotic association is found in the coralloid root of cycas.

Additional Information

• Cycas is the gymnosperm plant.
• In cycas roots are of two types i.e**. tap root and coralloid roots.**
• The association of fungi with roots of (pinus)higher plants known as mycorrhiza.
• The algal association with fungi is known as lichen.
• The algal association is found in the leaves of Azolla for nitrogen fixation.
• The algal association is found in the stems of gunnera.
• The algal association is found in root nodules of Trifolium.
• The algal association is found in the thallus of anthocerous.
• Anabaena and nostoc are the blue-green algae which form symbiotic relation.

Concept-

• Java man fossil obtains from central java by Dubois.
• They live in caves. And used tools of bones and stones.
• Time of origin is 1.5 - 2 million years ago.
• The first man who used fire for hunting, protection, and cooking.
• They are also known as erect ape-man.

Explanation-

• Homo erectus name of java man given by Mayer.
• Pithecanthropus erectus name of java man was given by Dubios.

So option 4 is correct.

Additional Information 

Concept-

• When the quantity of acids in the raining water is more than the average, then such rain is called 'Acid rain'.
• Acid rain means the presence of excessive acids in rainwater.
• This word was given by Robert August.
• Acids come down on earth with rainwater is called acid rain.
• We are aware that normally rainwater has a pH of 5.6.  When the pH of the rainwater drops below 5.6, it is called acid rain.

Explanation-.

• Smokes from different sources dissolved in atmospheric water vapour to form sulphuric acid and nitric acid.
• Sulfur and Nitrogen particles that get mixed with water are found in two ways either man-made as the emissions are given out from industries or by natural causes.

2SO₂ + O₂ + 2H₂O → 2H₂SO₄ 

4NO2 + O2 + 2H2O → 4HNO₃

• These acids come down on earth.
• SO2 and NO2 after oxidation and reaction with water are major contributors to acid rain because polluted air usually contains particulate matter that catalyzes the oxidation.

Thereby the main component of acid rain is sulphuric acid and nitric acid.

Additional Information

• Smog is fog and smoke.
• Smog is a type of intense air pollution that reduces visibility.
• Smog is a mixture of smoke (composed of minute particles of carbon, ash, and oil, etc. from coal combustion) and fog in suspended droplet form.
• It is the most common kind of air pollution that occurs in cities throughout the world.
• There are 2 types of smog- Classical and Photochemical smog.
• Classical smog (London smog) occurs in a cool and humid climate. It is reducing in nature.
• Photochemical smog (Los Angeles smog) occurs in a sunny and dry climate. It is oxidizing in nature.
• Smog falls under the category of particulate pollutants since it is composed of very minute particles.
• Long-term exposure to smog can be harmful to human health.

Concept-

• An important feature of all living cells is respiration which is related to the liberation of metabolic energy as ATP.
• Respiration is an amphibolic and exergonic cellular process.
• Respiration is of two types.
• Aerobic respiration- with the use of oxygen. Eg plants
• Anaerobic respiration- without the use of oxygen. Eg yeast
• Steps of aerobic respiration- Glycolysis, Krebs cycle, ETS.
• The term glycolysis has originated from the Greek words, glycos for sugar, and lysis for splitting.
• The scheme of glycolysis was given by Gustav Embden, Otto Meyerhof, and J. Parnas, and is often referred to as the EMP pathway.
• In anaerobic organisms, it is the only process in respiration.
• Glycolysis occurs in the cytoplasm of the cell and is present in all living organisms.

Explanation-

• In this process of glycolysis, glucose undergoes partial oxidation to form two molecules of pyruvic acid.
• In plants, this glucose is derived from sucrose, which is the end product of photosynthesis, or from storage carbohydrates.
• Sucrose is converted into glucose and fructose by the enzyme, invertase, and these two monosaccharides readily enter the glycolytic pathway.
• Glucose and fructose are phosphorylated to give rise to glucose-6- phosphate by the activity of the enzyme hexokinase.
• This phosphorylated form of glucose then isomerizes to produce fructose-6- phosphate.
• Subsequent steps of the metabolism of glucose and fructose are the same.
• In glycolysis, a chain of ten reactions, under the control of different enzymes, takes place to produce pyruvate from glucose.

Therefore the end product of glycolysis is pyruvic acid.

Note- One can easily get the answer to this question by looking at the diagram given above.

Important Points

• In glycolysis 6 or 8 ATP is formed.

Concept-

• Microbes are tiny living organisms.
• They believed to be primitive relatives of animals.
• Microbes that cause diseases are called pathogens.
• The most common types are bacteria, viruses, fungi, and protozoa.
• Protozoa is 3rd largest phylum.
• Protozoa include unicellular eukaryotes.
• Kala-azar caused by protozoa.

Explanation-

• Kala Azar, also known as Leishmaniasis, is a parasitic disease caused by protozoa.
• The causative agent of kala-azar is Leishmania donovani.
• Kala-azar is transmitted through the bite of an infected sandfly.
• Scientific name of sandfly is phlebotomus.

Thereby the kala-azar is transmitted by phlebotomus.

Additional Information

• Effect of kala-azar -
• Skin (Cutaneous Leishmaniasis)
• The mucous membrane of the mouth, throat, and nose (Mucocutaneous Leishmaniasis)
• Liver, lymph nodes, spleen, and bone marrow (Visceral Leishmaniasis)
• Symptoms of kala-azar -
• Skin ulcers
• Ulcers in the mouth, throat, and nose.
• Nosebleed.
• Difficulty in breathing.
• Weakness, weight loss, loss of appetite.
• Enlarged spleen, liver, lymph nodes.
• A decrease in the production of blood cells.

Concept-

• Sperm(spermatozoa) is the male gamete. The sperm unites with (fertilizes) an ovum (egg) of the female to produce a new offspring.
• A sperm has three main parts:
• The head of the sperm contains an elongated haploid nucleus, which holds the DNA of the cell, and the anterior portion is covered by a cap-like structure acrosome.
• The midpiece of the sperm is packed with mitochondria. Mitochondria are organelles in cells that produce energy. Sperm use the energy in the midpiece to move.
• The tail of the sperm moves like a propeller, around and around. This tail is a long flagellum that pushes the sperm forward.
• Spermatids are haploid cells formed by the meiotic division of spermatocytes and develop into spermatozoa after maturational events.

Explanation-

• Epididymis has 3 parts-
• Upper, highly coiled part- Caput epididymis
• Middle part- Corpus epididymis
• Basal, least coiled part- Cauda epididymis
• The epididymis can temporarily store the sperms for as long as one month and maturation also takes place.

Therefore maturation of spermatozoa occurs in the epididymis.

Important Points

• The process of the formation of sperms is called spermatogenesis.
• It involves 3 phases-
• In the multiplication phase, male germ cells also called spermatogonia, which undergo mitotic divisions to form a large number of spermatogonia.
• In the growth phase, spermatogonia prepare for meiotic division by increasing their size and called primary spermatocytes (46 chromosomes).
• In the maturation phase, the primary spermatocyte undergoes the first meiotic division and produces 4 haploid cells called secondary spermatocytes (23 chromosomes), which after the second meiotic division produces four equal, haploid spermatids.

Additional Information

Prostate-

• This gland is located below the urinary bladder.
• It secretes a slightly alkaline prostatic fluid which is milky, thick, sticky, or jelly-like.
• It makes about 30% part of semen and helps in sperm activation.

Vas deferens-

• The sperms reach the abdominal cavity due to the pulsation of the vas-deferens.
• The wall of vas-deferens is made up of 2 layers outer circular muscle layer and the epithelium.

Concept-

• Teeth are ectomesodermal in origin.
• Teeth are differentiated into three parts-
• Crown - It is the outer part of the tooth, exposed outside gums.
• Neck - It is the internal part of the tooth which is embedded inside the gums.
• Root - It is the part of the tooth that is inserted inside the socket of jawbones.
• Four types of teeth found in mammals are-
• Incisor- These are the teeth for gnawing the food. The tusk of elephants is a modification of upper incisors.
• Canines- These are the teeth for tearing and shearing the food.
• Premolars- These are teeth are meant for chewing and crushing food.
• Molars- These are also meant for chewing and crushing food.

Explanation-

The dental formula of the elephant is $\dfrac{1033}{0033}$.

• The teeth of the elephant are-
• Incisor = 1/0.
• Canine = 0/0
• Premolar = 3/3
• Molar = 3/3

Additional Information

• Human beings have four types of teeth are Incisors, Canine, Molar, and Premolar.
• A normal adult mouth has 32 teeth.
• Incisors (8) help in biting into the food.
• Canines (4) help in tearing the food.
• Molars (12) help in grinding the food.
• Premolars (8) help in crushing the food.
• The dental formula of human is 2123/2123.

Concept-

• Rhythmic contraction and relaxation of the heart are called heartbeat.
• The adult human heartbeat is 72 per minute.
• Hearts are of two types- myogenic and neurogenic heart.
• Myogenic heart- Impulse comes from outside the heart.
• Neurogenic heart- Impulse develops within the heart.

Explanation-

• In the myogenic heart, the impulse of heartbeat develops within the heart.
• In the myogenic heart, the impulse is generated by a special muscular tissue.
• The myogenic heart will continue to beat for some time if a detached heart is supplied with proper nourishment and favourable conditions.
• The myogenic heart is present in molluscs and vertebrates.

Thereby the heartbeat in vertebrates is myogenic.

Additional Information

Neurogenic heart-

• The impulse comes from the outside heart.
• Impulse is generated by the nervous system.
• The heart will stop beating if removed from the body.
• The neurogenic heart is found in Arthropoda and some annelids.

Concept-

• Silkworms are a group of insects (moths), which are species-specific to their host plants.
• Silk threads are obtained from the cocoon which is a protective covering around the pupa of these worms.
• The following silk from silkworm-
• Mulberry Silkworm - Bombyx mori
• Tasar Silkworm - Antherea roylei
• Muga Silkworm - Antheraea assama
• Eri Silkworm - Attacus ricini

Explanation-

• The silk fibre is a protein produced from silk glands of the silkworm.
• Silk glands are modified salivary gland of the caterpillar larva of the insect Bombyx mori.
• These caterpillar form a cocoon around them.
• The cocoon is cooked in hot water this process is called stiffing and the silk fibre is unwound from cocoons.

Thereby silk gland of silkmoth is modified salivary glands.

Important Points 

• Life Cycle of silkworm
• Stage 1-The cycle starts when female silk moth lays eggs.
• Stage 2- The caterpillar of larvae is hatched from the eggs of the silkmoth and they feed on mulberry leaves and consume a large amount of these leaves for around 30 days.
• Stage 3-The silkworm spin a protective cocoon around itself.it is the size of a small cotton ball and is made of a single thread of silk.
• Stage 4- Then Pupa changes into an adult moth. The female moth lays eggs after mating and thus the life cycle of silkworm begins again.
• Eggs → Caterpillar → Pupa → Butterfly

Additional Information

• India is the only country in the world having all four varieties of silk.
• The commercial silk is obtained from cocoons secreted by salivary glands of mulberry silkworm Bombyx mori and the practice of rearing it for silk production is called Sericulture.

Concept-

• Soft contractile tissues present in the human body that supports the movement of different parts of the body are called muscles.
• In a human body there exist three types of muscles-

Explanation-

• Transverse lines are found at regular intervals i.e., called striped muscle.
• The muscle fibers attached to a tough cord of connective tissue called the Tendon and tendon further attached with a bone.
• Striped muscles are also known as skeletal muscles.
• Striated muscle are attached to bones through tendons and are directed by conscious control of the Brain hence called voluntary muscles.
• Skeleton muscles are attached to the bones by means of tendons, and they are responsible for all kinds of movements in vertebrates.

Thereby all muscles that are attached to bones are only striped.

Additional Information 

• The tissue connecting the bones to the muscles is called the tendon.
• The tissue connecting bones to bones are called a ligament.
• The total number of muscles in the human body is 639.
• The structure of the human body is made of bones, there are muscles above the bones, due to which we can move the bones.
• The Gluteus maximus is the biggest and heaviest muscle in the human body.
• Sartorius is the longest muscle of the body.
• The stapedius is the smallest muscle of the body.
• The masseter is the strongest muscle of the body.

Explanation-

• Cimex lectularius, the common bed bug, is best known as it prefers to feed on human blood.
• Bed bugs are mainly active at night but are not exclusively nocturnal.
• The life cycle of a bed bug-
• Stage 1 - A female bed bug lays eggs up to 500 eggs. They are white in color. The eggs hatch in two weeks, and nymphs emerge.
• Stage 2 - The Nymph, which hatches from the egg is the second stage of the life cycle of the bed bug.
• Stage 3 - It takes five weeks for a nymph to become an adult. An adult bed bug lives for four to six months.
• Eggs → Nymph → Bed bug

Thereby an insect without pupa stage is a bed bug.

Additional Information

Silkmoth-

• Silkworms are a group of insects (moths), which are species-specific to their host plants.
• Silk threads are obtained from the cocoon which is a protective covering around the pupa of these worms.
• Life Cycle of silkworm
• Stage 1 - The cycle starts when a female silk moth lays eggs.
• Stage 2 - The caterpillar of larvae is hatched from the eggs of the silkmoth and they feed on mulberry leaves and consume a large amount of these leaves for around 30 days.
• Stage 3 -The silkworm spin a protective cocoon around itself.it is the size of a small cotton ball and is made of a single thread of silk.
• Stage 4 - Then Pupa changes into an adult moth. The female moth lays eggs after mating and thus the life cycle of the silkworm begins again.
• Eggs → Caterpillar → Pupa → Butterfly

Mosquito-

• Common mosquitoes are Anopheles, Culex, and Aedes.
• They are small nocturnal insects.
• The developmental stages of an adult mosquito, from its egg to an adult, is called metamorphosis.
• The life cycle of a mosquito
• Stage 1 - Mosquito Egg eggs are small, nearly 200-300 eggs. This stage lasts for 24-48 hours.
• Stage 2 - Larva emerges out from the egg within 48 hours they eat algae and small organisms in the water. This stage lasts for 7-14 days.
• Stage 3 - Pupa formed from larva, floats in water. This is the hibernating stage when the pupa does not eat and only rest/sleep. This stage lasts for 1-4 days.
• Stage 4 - Adult mosquito splits the pupa case and comes out on the surface of the water. Female mosquito feeds on blood.
• Eggs → Larva→ Pupa → Mosquito

Explanation:

• Protein synthesis is a process of production of proteins required for the cells of any living organism. Proteins are biomolecules needed by our body for the growth and multiplication of cells.
• Proteins are also known as building blocks of life. Proteins perform numerous functions in our body. Some proteins are a part of the structure of cells, those are called Structural proteins.
• Some proteins act as Enzymes which are biological catalysts or bio-catalysts.  These enzymes speed up the rate of a reaction without taking part in the reaction. Some proteins act as Hormones That regulate the functioning of our body.
• These proteins are made up of many smaller subunits which are called amino acids. These amino acids are monomers that join with each other in a specific sequence to form a polymer (bigger molecule) of protein.
• Amino acids are synthesized inside the cells, Thus the process of formation of proteins is also known as Bio-synthesis of proteins or Protein synthesis.
• Protein synthesis is a process that initiates inside the nucleus and completes in the cytoplasm on the surface of the rough endoplasmic reticulum.
• The process of protein synthesis includes Transcription and Translation.

1. Transcription: It is the process of copying genetic information from one strand of DNA to single-stranded mRNA. During this process synthesis of a complementary RNA, strand takes place.
2. Translation: Translation is the mechanism in which coded information is translated & specific amino acids are prepared which forms a polypeptide on ribosomes.

• The process of protein synthesis is very important for every living organism. Any change or problem in protein synthesis causes severe physiological disorders.

Additional Information

• Different cell organelles perform different functions in our body.
• Nucleus: The Nucleus is an important cell organelle that contains and controls the genetic material of the cell. As the nucleus has entire genetic information of the cell, it also plays an important role in heredity and variation. It is the characteristic cell organelle in Eukaryotic cells.
• Smooth Endoplasmic Reticulum: It is a little network that connects the nucleus & the cytoplasm. If the Endoplasmic reticulum has ribosomes attached to it, it is called a rough endoplasmic reticulum. If the endoplasmic reticulum lacks ribosomes, it is known as Smooth endoplasmic reticulum. Smooth ER is involved in various processes like a synthesis of lipids, detoxification of drugs & poisons, storage of calcium ions, etc.
• Chloroplast: The chloroplasts are plastids which contain a green coloured pigment known as Chlorophyll. Chloroplasts are present in plant cells. It is the active site for photosynthesis.

Concept:

• Elimination of metabolic wastes products from our body is called as Excretion. These waste products are the by-products of various biochemical processes carried out in body as a part of our body metabolism. These metabolic waste products may be fluid, gaseous, organic or inorganic in nature. these metabolic by-products being toxic and harmful for our body needs to be eliminated out of our body timely through various organs of our body of an organism.
• In case of unicellular organisms, the body is made up of one cell only, so excretion takes place through that single-cell only but in the body multicellular organisms, a specialized organ system is present to carry out the function of excretion. This specialized system dedicated to carrying out excretion is known as the excretory system.
• in Human body also a highly specialized excretory system is present. The human excretory system consists of the following organs-

1. A pair of kidneys.
2. A pair of ureters.
3. Urinary bladder.
4. Urethral opening.

• A Pair of bean-shaped kidneys is present on the ventral side of our body from 12^th thoracic to 3^rd lumbar vertebra. since it is present on ventral side of our body thus, it is called Retroperitoneal. The functional unit of the kidney is called Nephron. Each kidney has almost 1 million Nephrons. Kidneys bring about separation & elimination of nitrogenous wastes, excessive water and toxic substances from our body. Kidneys also maintain homeostasis by osmoregulation & regulation of pH of our body fluids. Kidneys also secret hormones like Erythropoietin which is essential for the production of RBCs.
• Ureters are two tubes which connect kidneys to urinary bladder. Each ureter is a long muscular tube about 25-30cm in length. Ureters transport urine from renal pelvis to urinary bladder.
• Urinary bladder is a hollow, muscular sac-like organ. It is of inverted triangular shape which is called Trigone. Urinary bladder is a temporary storage organ for urine. It is made up of three layers of smooth muscles which helps bladder to stretch. Urinary bladder can store on an average 700ml of urine till micturition (expellation of urine).
• Urethra is a passageway for discharging urine from our body. In Human females, opening for urethra is different from genital opening (vagina)but in human males, urethra acts as a urogenital organ.

​Explanation:

• The structural and functional unit of the kidney is Nephron. Each nephron consist of about 4-6 cm long thin-walled tube- 'renal tubule' & a bunch of  capillaries-'glomerulus'
• Glomerulus is present in the cup-like cavity of Bowman's capsule and both are collectively known as renal corpuscle or Malpighian body. A small terminal branch of renal artery called as afferent arteriole enters this cup-like cavity and undergoes fine branching forming many thinly walled capillaries. this bunch of capillaries is Glomerulus. The function of the erulus is ultrafiltration. It finely filters out nutrients present in urine to avoid removal of useful nutrients outside the body.

• The movement of substances from the blood within the glomerulus is called ultrafiltration / glomerular filtration. The blood (plasma) flowing through glomerulus is filtered at rate 125ml/min. this filtrate is termed as glomerular filtrate or primary urine.
• This primary urine is alkaline, contains urea, amino acids, glucose, pigments & inorganic ions.  Although it contains amino acids, Albumin is not normally present in urines if kidneys are functioning properly.
• If protein Albumin is detected in the urine it indicates malfunctioning of kidneys. such a phenomenon is called Proteinuria. It is characterised by symptoms like frothy, foamy urine and swelling of hands, legs abdomen or face.

so, Glomerular filtrate will not contain normally albumin.

Concept:

• The stele is defined as a central core of vascular bundles with or without pith.
• The endodermis is the boundary between cortex and stele.
• Types of stele:

1. Protostele
2. Siphonostele
3. Dictyostele
4. Eustele

Explanation:

• Protostele is found in ''Lycopodium''
• Protostele: The vasculature consists of the central core of the xylem completely surrounded by phloem. This is the most primitive and simplest type of stele. It is of the following type:

1. Haplostele: This is the most primitive type of protostele. Here the central solid core of the xylem is surrounded by a layer of phloem. e.g., Selaginella
2. Actinostele: Central xylem core with radiating ribs or a star-shaped appearance surrounded by phloem, more advance than haplostele. e.g., Psilotum
3. Plectostele: Xylem is plate-like arranged parallel to each other and is surrounded by phloem. More advance than actinostele. e.g., Lycopodium.

​

Additional Information  

• Marsilea has  Amphiphloic siphonostele. In this type of stele, the center is occupied by pith. The xylem is surrounded on both the external and internal sides by a ring of phloem.
• Equisetum stem has Eustele. In this type of stele, the vascular system consists of a ring of collateral, conjoint vascular bundles situated on the edges of the pith.