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The correct answer is Centriole.

Explanation :

• Centrioles are present in animal cells and absent in plant cells.
• They are the microtubules organizing regions which organize the position of mitotic spindles during cell division.
• Plants have a rigid cell wall that can itself organize the spindle forming microtubules during cell division.

Key Points

• Structure of Centriole :
• A centriole is a barrel-shaped structure located in the cytoplasm of animal cells.
• A pair of centrioles make the organelle centrosome.
• The centrioles appear as 2 cylinders at right angles to each other.
• The wall of the centriole is made of 9 triplets fibres arranged around a central axis.
• Each fibre consists of 3 sub-fibres or sub-tubules lying parallel to each other.
• It looks like a cart-wheel structure with a central rod or hub radiating 9 spokes, each of which is connected to a fibre.
• ​Functions of Centriole : 
• They are involved in mitosis for formation of spindle fibers.
• Spindle fibres attach to the kinetochore discs present at the centromere and help in the movement of chromatids during chromatid separation.
• They also form the mitotic apparatus during mitosis or meiosis.
• In primitive flagellates, they function as basal bodies for the flagella.

Additional Information

• ​A large central vacuole :
• ​The vacuole is the membrane-bound space found in the cytoplasm of plant cell.
• The membrane of the vacuole is known as tonoplast.
• It contains water, sap, excretory product and other materials not useful for the cell.
• 70 S Ribosome :
• Ribosomes are very important cellular component that are used for synthesis of proteins from RNA.
• The 70S ribosome consists of 2 subunits - 50S and 30S, which take part in the translation process.
• 70S ribosomes are mostly found in prokaryotic cells, but are also present in the chloroplast in plant cell.
• This is supported by the 'Endosymbiotic Theory' that proposes that chloroplasts and mitochondria are remnants of primitive prokaryotic cells that became a part of plant cell to perform specific functions.
• These cells have later evolved as the cell organelles to perform photosynthesis and respiration.
• 80 S Ribosome :
• ​Plant cells have three distinct ribosome species; 80 S ribosomes in their cytosol, 70 S-like ribosomes in their chloroplasts and mitochondria.
• Eukaryotic ribosomes are 80S ribosomes that consists of 2 subunits- 60S and 40S.

The correct answer is Hardened resinous secretion.

Explanation:

• 'Amber' is a fossilized form of hardened resinous secretion.
• Resin is a sticky, viscous substance secreted by plants to protect them from predators and pests.
• Amber is made from resin exuded from tree bark, but it can also be found in the heartwood.
• Resin protects trees by filling gaps in the tree bark.
• When resin covers a break that is caused by a chewing insect, it hardens and forms a seal.
• Thus amber often contains insects preserved in it as they might have got stuck in the sticky resin years ago.

Important Points

• Colour - All shades of yellow.
• Shape - Irregular nodules, rods or drop-like shapes.
• Occurences - Largest deposits are found along the shores of Baltic Sea.
• Some other properties:
• It may contain microscopic air bubbles.
• Baltic amber often contain minute hair-like inclusions, apart from insects.
• The surface changes its colour and opacity on exposure to oxygen in air - it becomes darker and opaque.
• When kept in oxygen-free environment, they retain their original colour and appearance.
• Uses -
• Deeply coloured translucent or transparent forms are valued as gems.
• Used for making decorative items and jewelry.
• Healing agent in folk medicine.
• Study of fossils that are preserved inside the hardened resin.
• It is also used for aesthetic purposes.
• In ancient times, it was used as a natural magnifier.
• Transparent amber with a convex surface was used as burning lenses for concentrating sun's rays.

A dwarf shoot with two needles is found in Pinus Sylvestris.

Key Points

• Pinus is a ''Coniferous gymnosperm''.
• These are large trees having pyramidal or ''excurrent shape'' like a ''Christmas tree''.
• Pinus has both male and female cones present on the same tree.
• Male cone occurs in a cluster, subterminally on lower long braches.
• The female cones develop in a group of 2-6 on the upper long branches of the tree.
• It has a sporophytic plant body that is differentiated into root, stem and needle-like leaves.
• There are 2 types of branches - long shoot and dwarf shoot.

Important Points

• The leaves of Pinus are of 2 types:
• Foliage - are large, needle-like and present at the apex of dwarf shoots only.
• Scaly - are thin, brown, scale-like and is present on both long and dwarf shoots.
• Foliage leaves vary in number from 1-5 in different species.
• The dwarf shoot with needles is called a spur.
• Depending on the number of needles, spurs can be of the following types:
• Unifoliar - Only 1 leaf or needle present at the apex of dwarf shoot. E.g. - Pinus monophylla.
• Bifoliar - with 2 needles. E.g. - Pinus sylvestris.
• Trifoliar - with 3 needles. E.g. - Pinus gerardiana.
• Quadrifoliar - with 4 needles. E.g. - Pinus quadrifolia.
• Pentafoliar - with 5 needles. E.g. - Pinus wallichiana.

The correct answer is Perianth.

Explanation:

• Now the Gramineae family is known as Poaceae family.
• Graminae is a grass family of monocotyledonous flowering plants.
• The Poaceae are the world's most important food source.
• Grass, wheat, rye, and other cereal grains are primary members of the Gramineae family.

Important Points

• The inflorescence present in Graminae is called spikelet.
• Each spikelet consists of a short axis called rachilla, which bears a number of bracts, bracteoles and flower.
• The 2 lowermost bracts are sterile and termed as empty glumes.
• The third bract is flowering and called as lemma.
• There is a bracteole called palea placed opposite the lemma.
• Each spikelet may contain one or more flowers, where the lemma bears the flower in its axil.
• The perianth is the outer part of a flower that includes the calyx (sepals) and corolla (petals).
• In Graminae, the perianth is represented by lodicules.
• Lodicule - is a structure that consists of one to three small scales at the base of the ovary.
• In the Graminae family, two or three lodicules (minute scales) represent the perianth.
• The lodicules are present between the lemma and ovary base.
• Their main function is to swell rapidly at maturity to force apart the lemma and palea.
• Thus they help in assisting anthesis, allowing the anthers and stigma to emerge for pollination.

The correct answer is Head.

Explanation: 

Tentorium - It is formed by ingrowths of the exoskeleton (made of chitin), which fuse in various ways to provide rigid support for the muscles of the head.

Key Points

• The common cockroach is scientifically known by the name Periplaneta americana.
• General Characteristics of Cockroach :
• They are brown or black-bodied & a dioecious animal, with separate male and female sexes.
• They are included in class Insecta of Phylum Arthropoda.
• They are nocturnal omnivores that live in damp places throughout the world.
• The entire body is covered by a hard chitinous exoskeleton.
• The body of the cockroach is segmented and divisible into three distinct regions – head, thorax, and abdomen.

1. Head -

• Head is triangular in shape, head capsule bears a pair of compound eyes.
• In front of the eyes, membranous sockets are present, out of which two antennae protrude out.
• The head also has appendages that bear similarity to the mouthparts, such as the labrum, a pair of mandibles, a pair of maxillae and a labium.
• There is also a flexible lobe called the hypopharynx that acts as a tongue.

2. Thorax -

• The thorax is further divided into - prothorax, mesothorax, and metathorax.

3. Abdomen -

• The abdomen is made up of 10 segments.
• The 7^th, 8^th, and 9^th sterna form a genital pouch in females.
• The male cockroach has thread-like anal styles, which are missing in the female cockroach.​​

Important Points

• The endoskeleton is formed by the internal extensions of the exoskeleton.
• Such endoskeletal elements are known as apodemes, which help in attachment of muscles.
• The apodemes of the head form a characteristic structure called tentorium.
• The tentorium is present below the occipital foramen in the head.
• It has a central space for the passage of nerves and 3 pairs of arms - anterior, posterior and dorsal.
• The apodemes of the thoracic region is meant for attachment of leg muscles.
• Endoskeleton is absent in the abdomen.

Concept-

• Cycas are seed-producing plants that belong to the Gymnosperms.
• Cycas have a dominant diploid sporophyte phase in their life cycle.
• It is strictly dioecious, i.e., male and female organs are borne on separate plants.
• The microspores develop in the microsporangia after meiosis.
• The male gametophyte development takes place in 2 phases, pre- and post-pollination.

Important Points

• The male gametes (spermatozoids) of Cycas are the largest in the plant kingdom.
• Their size varies from 180-210µm and are visible to the naked eye.
• The spermatozoids of Cycas are top-shaped, motile, and multiciliate.
• They have 5-6 spiral bands of thousands of cilia, which help them move in the pollen tube.

Additional InformationMale Gametophyte Development -

1. First Stage of development -

• The development of male gametophyte takes place in the sporangium.
• The nucleus divides into two and one moves to the lower side and is separated from the other by a crescent-shaped wall.
• This results in two unequal cells - lower smaller prothallial cell, upper larger antheridial cell.
• The antheridial cell divides to form a generative cell and a distal tube cell.
• This is the 3-celled stage at which the pollen grains are shed as the microsporangia dehisce.

2. Second Stage of development -

• Pollen grains get stuck to the pollination drop on the ovule.
• The pollination drop is a viscous fluid that collects at the micropyle end and gradually dries up.
• As a result the pollen grains are sucked into pollen chamber and the micropyle is sealed.
• After a period of rest of up to 4 months, the exine breaks and pollen tube comes out.
• Pollen tube enters the archegonial chamber through the nucellar tissue.
• The generative cell divides to form a stalk cell and a body cell.
• Two blepharoplasts appear at 2 poles of body cell nucleus.
• The body cell divides longitudinally to form 2 sperm cells.
• Each sperm cell develops into a spermatozoid (sperm) and blepharoplast into cilia.
• The sperm mother cell ruptures to release the sperms into the pollen tube.

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 bodied and shelled" animals.

Explanation-

• Pila is herbivorous, feeding on algae and plants.
• The mouth leads into a cuticle-lined buccal cavity.
• On the floor of the buccal cavity, there is a structure called odontophore.
• Odontophore is an elongated, muscular, and cartilaginous structure that bears a membranous belt called a radula.
• The radula which lies in a radular sac has transverse rows of teeth.
• Each row has seven teeth: 2 marginal and 1 lateral tooth on each side and 1 central tooth in the middle.
• Thus, giving a formula 2, 1, 1, 1, 2.
• These help to cut the food into bits.

Therefore, in Pila 21112 teeth are present in each row of radula.

Additional Information

• Pila is also called an Apple snail.
• Pila respire by gills in water or by pulmonary sac on land.
• The larva of pila is veliger.

The correct answer is a - 3, b - 2, c - 4, d - 1.

Explanation:

Epistatic gene-

• An epistatic gene is one that masks or hides the phenotypic effect of another gene.
• Thus, Epistatic gene masking the action.

Translocation-

• Chromosome translocation is a genetic condition that results in the Interchromosomal rearrangement.
• Thus, translocation causes interchromosomal rearrangement.

Neomorph-

• A neomorphic mutation results in a dominant gain of gene function that is not the normal function.
• Changing the dose of a wildtype gene has no influence on the phenotypic of a neomorph.
• Hence, neomorph produce a phenotype different from the wild gene.

Co-dominance-

• When the F₁ generation resembles both the parents, and both the parental characters are expressed simultaneously, then the phenomenon is called Co-dominance.
• For example, 'AB' type blood group is possible when allele 'A' and 'B' come together and since both the allels are expressing their effects in F₁ generation, they are co-dominants.
• Hence, Co-dominance character is controlled by two genes.

The correct answer is more than 1.

Hint

Respiratory substrate & Respiratory Quotient (RQ) 

• The respiratory substrate is broken down to release energy in the process of respiration. Aerobic and anaerobic respiration are the main two types of respiration that occur in the presence or absence of molecular oxygen. Glucose is the most common respiratory substrate present in plants.
• During aerobic respiration, O₂ is consumed and CO₂ is released.
• "The ratio of the volume of CO₂ evolved to the volume of O₂ consumed in respiration is called the Respiratory Quotient (RQ) or Respiratory Ratio."
• Respirometer is an instrument used for measuring the rate of respiration as well as R.Q.

RQ Value is calculated using the given formula : 

\(RQ = \frac{Volume\ of \ CO_2 \ evolved }{Volume\ of \ O_2 \ consumed}\)

The respiratory quotient depends upon the type of respiratory substrate used during respiration.

Explanation:

RQ of Organic acids (More than 1)

• Organic acids like - Malic acid (Refer below reaction), Tartaric acid, Oxalic acid are rich in O₂ and require less O₂  for their oxidation, so when the organic acids are oxidized in respiration, the value of R.Q. is greater than one. The reaction & RQ is given below :

​C₄H₆O₅ (Malic acid) + 3O₂  → 4CO₂ + 3H₂O + Energy

\(RQ = \frac{Volume\ of \ CO_2 \ evolved }{Volume\ of \ O_2 \ consumed} = \frac{4}{3} = 1.33 \)

Important Points

Significance of RQ:

• Helps in determining the type of respiration being performed.
• Determine the nature of the respiratory substrate that oxidized the transformation of the substrate and the biochemical mechanism of respiration.
• Knowing the metabolic rate.
• Determination of various pathological conditions like acidosis, alkalosis, etc.

Additional Information

1. RQ of Succulent plants  [Zero]

• In succulent plants like - Bryophyllum, Opuntia, etc., stomata remain open during the nighttime. So, at night when oxygen is absorbed, the carbohydrates are partially oxidized to organic acids without the formation of CO₂. So, the value of R.Q. remains zero.
• During the day, the value of RQ remains zero because the CO₂ released during respiration is used up as a substrate for photosynthesis

​2C6H12O6 (Glucose) + 3O2  → 3C₄H₆O₅ (Malic acid) + 3H2O + Energy

\(RQ = \frac{Volume\ of \ CO_2 \ evolved }{Volume\ of \ O_2 \ consumed} = \frac{0}{3} = 0\)

      2. RQ of Carbohydrates [1]

• When carbohydrates are used as substrate and are completely oxidized, the RQ will be 1, because equal amounts of CO₂ and O₂ are evolved and consumed, respectively.

​ C₆H₁₂O₆ + 6O2  (Glucose) → 6CO₂ + 6H2O + Energy

\(RQ = \frac{Volume\ of \ CO_2 \ evolved }{Volume\ of \ O_2 \ consumed} = \frac{6}{6} = 1 \)

     3. RQ of Fats [Less than 1]

• Fats need more amount of O₂ for their oxidation as compared to other substrates. Fats are usually present in seeds as storage food in plants.
• Fats need more amount of O₂ for their oxidation as compared to other substrates.
• R.Q. value is less than one or unity in the aerobic respiration of fats**.**

​2C5 H98O6 (Tripalmitin)+ 145O2  → 102CO2 + 98H2O + Energy

\(RQ = \frac{Volume\ of \ CO_2 \ evolved }{Volume\ of \ O_2 \ consumed} = \frac{102}{145} = 0.7 \) (Less than 1)

     4. RQ of Proteins & their derivatives [Less than 1]

• Proteins are building blocks of the living body and are made up of amino acids.
• When the cells are going to starvation, then proteins act as a respiratory substrate.
• When proteins are respiratory substrates the ratio would be about 0.9.
• Protein structures vary with changes in amino acid sequence.
• So, the value of R.Q. also varies from 0.8 - 0.9 depending upon the structure of different amino acids.

​2C3H₇O₂ N(Alanine)+ 6O2  → CO(NH₂)₂  (Urea) + 5CO2 + 5H2O + Energy

     5. RQ of Aerobic respiration [More than 1]

• In aerobic respiration, when respiratory substrate is fat or protein, R.Q is less than 1.
• When carbohydrate is the substrate, R.Q is 1.

The correct answer is Mutation theory.

Key Points

• Charles Darwin : British naturalist and evolutionary biologist Charles Darwin is known as the "Father of Evolution", credited for the theory of natural selection.
• Pangenesis theory (1868):
• It was given by Charles Darwin.
• It states that every part of the body emits tiny particles called gemmules which migrate to the gonads and are transferred to offspring.
• These particles are then transmitted to the next generation and are responsible for the transmission of characteristics from parent to offspring.
• Mutation theory (1901) :
• Dutch botanist and geneticist Hugo de Vries gave rise to the Mutation theory.
• According to his theory, mutation causes evolution by formation of new species or speciation.
• Mutations refer to the changes in the genes of organisms that greatly altered the organism.
• These changes are passed down to the next generation and lead to the development of new species.

Additional Information

Darwin gave rise to two theories 

1. Theory of Natural Selection (1859) : The slightest difference in traits like color or design can help or proves useful for animal or plant live, survive and reproduce better in the wild, that will retain naturally and get transferred to next generations. Various species originated from a single species as a result of adaptation to the changing environment, as per natural selection.
2. Theory of survival of fittest (1869) : This means that individuals in a population, or community, are more likely to survive if they are fit and the rest will die.