General Science PYQs

p data-end="57" data-start="0">The correct answer is holozoic.

 

Key Points

• Holozoic nutrition is a type of heterotrophic nutrition that involves the ingestion of liquid or solid organic material, followed by its internal digestion, absorption, and assimilation to provide energy.
• In this mode, the organism takes in the whole food material (complex organic substances) and breaks it down into simpler forms inside the body using specific enzymes. Hence, the statement in the question perfectly describes holozoic nutrition.
• The process of holozoic nutrition typically follows five distinct stages: Ingestion (taking in food), Digestion (mechanical and chemical breakdown), Absorption (nutrient uptake), Assimilation (utilization for energy/growth), and Egestion (elimination of waste).
• Common examples of organisms following this mode include Humans, Amoeba, Dogs, Cats, and Lions. In Amoeba, food is captured using temporary finger-like projections called pseudopodia.
• Organisms with holozoic nutrition are categorized into three types based on their food source: Herbivores (plant-eaters), Carnivores (meat-eaters), and Omnivores (those eating both plants and animals).

Additional Information

• Saprophytic Nutrition:
• Saprophytic organisms (saprobes) derive their nutrition from dead and decaying organic matter like fallen leaves, dead animals, or rotting bread.
• Unlike holozoic organisms, they perform extracellular digestion by secreting enzymes outside their body to break down complex matter and then absorbing the liquefied nutrients. Common examples include Fungi (like Mushrooms and Yeast) and certain Bacteria.
• Parasitic Nutrition:
• In this mode, an organism (the parasite) lives on or inside another living organism (the host) and obtains its food at the expense of the host without killing it immediately.
• They can be Ectoparasites (living outside, like Leeches and Lice) or Endoparasites (living inside, like Tapeworms and Ascaris). A famous plant parasite is Cuscuta (Amarbel).
• Autotrophic Nutrition:
• Autotrophs are organisms that can manufacture their own food from inorganic substances like Carbon dioxide (CO2) and Water (H2O).
• Most autotrophs use Photosynthesis, utilizing Sunlight and Chlorophyll to produce Glucose. This category primarily includes Green plants and Cyanobacteria (blue-green algae).

Important Points

• Key Biological Features:
• Heterotrophs: Both holozoic, parasitic, and saprophytic organisms fall under the broad category of Heterotrophs because they cannot produce their own food and depend on other sources for organic carbon.
• Digestive System: Holozoic nutrition usually requires a specialized digestive tract or a food vacuole (as in unicellular organisms like Paramecium) to process the ingested material.
• Comparison Summary:
• Holozoic: Internal digestion of solid/liquid food.
• Saprophytic: External digestion of dead matter.
• Parasitic: Absorption of nutrients from a living host.
• Autotrophic: Synthesis of food using Solar energy or Chemical energy.

The correct answer is Each piece will regenerate to form new individuals.

Key Points

• Hydra is a simple multicellular organism that possesses an incredible capacity for regeneration, which is a form of asexual reproduction when the body is divided.
• When a Hydra is cut into multiple pieces, each piece has the potential to grow into a complete, new individual. This happens because the organism contains specialized cells that can proliferate and differentiate into any cell type required to rebuild the missing parts.
• This process is driven by interstitial cells, which are totipotent stem cells found in the body column of the Hydra. These cells undergo rapid division to form a mass of cells that eventually organizes into the structures of a full organism.
• If the body is sliced transversely or longitudinally, the polarity of the organism is maintained, meaning the "head" part will grow a new "foot" and the "foot" part will grow a new "head." Hence, the statement that each piece will regenerate to form new individuals is correct.
• Unlike higher organisms where cutting leads to permanent injury or death, in Hydra, it results in the multiplication of the organism. Hence, the statement that all pieces will die immediately is incorrect.

Additional Information

• Phylum and Habitat: Hydra belongs to the phylum Cnidaria (specifically the class Hydrozoa). It is a freshwater organism typically found in unpolluted ponds, lakes, and slow-flowing rivers.
• Discovery: The remarkable regenerative powers of Hydra were first discovered and described by the scientist Abraham Trembley in the year 1744. His experiments were pioneering in the field of experimental biology.
• Budding vs. Regeneration: While Hydra can regenerate when cut, its primary mode of asexual reproduction under favorable conditions is budding. In budding, a small outgrowth (bud) develops due to repeated cell division at one specific site, which eventually matures and detaches from the parent. Regeneration is typically a response to injury rather than the standard reproductive cycle.
• Morphallaxis: The type of regeneration observed in Hydra is known as morphallaxis. In this process, the regeneration occurs mainly by the remodeling of existing body tissues into a new organism, rather than just the growth of new tissue at the wound site (which is called epimorphosis).
• Other Examples: Besides Hydra, organisms like Planaria (flatworms) and Starfish also exhibit high degrees of regeneration. In Planaria, even a tiny fragment can regenerate into a whole worm.

Important Points

• Biological Immortality: Hydra is often cited as being biologically immortal because its stem cells continually renew themselves, and it does not appear to die of old age or show signs of senescence.
• Body Structure: The body of a Hydra is diploblastic, meaning it consists of two main layers: the ectoderm (epidermis) and the endoderm (gastrodermis), separated by a gelatinous layer called the mesoglea.
• Nerve Net: It possesses a simple nerve net rather than a centralized brain, which coordinates its movements and responses to stimuli like touch or light.
• Feeding Mechanism: Hydra are carnivorous and use specialized stinging cells called nematocysts or cnidocytes located on their tentacles to paralyze and capture prey like small crustaceans (e.g., Daphnia).

The correct answer is both remain unchanged.

Key Points

• A neutral solution is a solution that is neither acidic nor basic in nature. It typically has a pH value of exactly 7 at 25 degrees Celsius.
• Litmus paper is a commonly used pH indicator made from paper treated with natural dyes extracted from lichens.
• In a neutral solution, red litmus paper stays red and blue litmus paper stays blue. Since neither paper changes its original color, they are said to remain unchanged. Hence, the correct answer is option 1.
• The lack of color change occurs because the concentration of hydrogen ions (H+) and hydroxyl ions (OH-) is equal in a neutral medium, providing no chemical stimulus to trigger the color-changing pigments in the litmus.
• Common examples of neutral substances include distilled water, sodium chloride (common salt) solution, and sugar solutions. These substances do not show any reaction with either type of litmus paper.

Additional Information

• Acidic Solutions:
• An acidic solution has a pH value of less than 7.
• In an acidic medium, blue litmus paper turns red, while red litmus paper remains red.
• Common examples include hydrochloric acid (HCl), sulfuric acid, lemon juice (citric acid), and vinegar (acetic acid).
• Basic (Alkaline) Solutions:
• A basic solution has a pH value of greater than 7.
• In a basic medium, red litmus paper turns blue, while blue litmus paper remains blue.
• Common examples include sodium hydroxide (NaOH), baking soda solution, soap solution, and limewater (calcium hydroxide).
• The pH Scale:
• The pH scale was introduced by S.P.L. Sorensen in 1909 to measure the acidity or alkalinity of a solution.
• The scale ranges from 0 to 14, where 0 is highly acidic, 14 is highly basic, and 7 is neutral.

Important Points

• Natural Indicators: Apart from litmus (derived from Roccella tinctoria), other natural indicators include turmeric (which turns red in bases), China rose (which turns dark pink in acids and green in bases), and red cabbage juice.
• Synthetic Indicators: Scientists also use laboratory-made chemicals like Phenolphthalein (which is colorless in acid and pink in base) and Methyl Orange (which is red in acid and yellow in base).
• Universal Indicator: This is a mixture of several indicators that shows different colors at different pH values, allowing for a more precise measurement of the strength of an acid or base.
• The term "neutralization" refers to the chemical reaction between an acid and a base to produce salt and water, resulting in a solution that typically does not change the color of litmus paper.

The correct answer is Crystallisation.

Key Points

• Crystallisation is the process of formation of solid crystals precipitating from a solution, melt, or gas. It is a physical change because the chemical composition of the substance remains the same; it only changes its physical state from a solute in a solvent to a solid crystalline structure. Hence, statement 1 is correct.
• Rusting is a chemical process that occurs when iron reacts with oxygen and moisture (water) in the atmosphere to form iron oxide. Since a new chemical substance is formed, it is a chemical change. Hence, statement 2 is incorrect.
• Combustion is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products. Because it results in the formation of new substances like carbon dioxide and water vapor, it is a chemical change. Hence, statement 3 is incorrect.
• Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In this process, substances like sugar are converted into alcohol or acids by microorganisms like yeast or bacteria. Hence, statement 4 is incorrect.

Additional Information

• Physical Change:
• A physical change is a type of change in which the form of matter is altered but one substance is not transformed into another.
• Key characteristics include changes in physical properties such as shape, size, volume, density, and state of matter (solid, liquid, gas).
• These changes are usually reversible. Examples include melting of ice, boiling of water, dissolving sugar in water, and shredding paper.
• Chemical Change:
• A chemical change occurs when a substance combines with another to form a new substance (synthesis) or decomposes into two or more different substances.
• These processes are called chemical reactions and are generally irreversible by simple physical means.
• Examples include digestion of food, burning of wood, cooking an egg, and souring of milk.
• Indicators of a chemical change often include color change, evolution of gas, formation of a precipitate, or change in temperature (heat absorption or release).

Important Points

• Distinguishing Features:
• In a physical change, no energy is typically produced, though it may be absorbed or released during state changes (like latent heat).
• In a chemical change, there is a significant exchange of energy, and the molecular composition of the substance is entirely transformed.
• Crystallisation is frequently used as a purification technique in laboratories and industries to obtain pure solids from impure mixtures. For example, obtaining pure copper sulphate from an impure sample.
• Rusting of iron can be prevented by methods such as galvanization (coating with zinc), painting, or greasing to block contact with air and moisture.

The correct answer is Sink, because its density is greater than water's density..

Key Points

• Density is defined as the mass of an object per unit volume. It determines whether an object will float or sink in a given fluid.
• In the given problem, the mass of the sealed packet is 500 g and its volume is 350 cm3.
• The formula for calculating density is Density = Mass / Volume. By substituting the values, we get: 500 g / 350 cm3 = 1.428 g/cm3 (approximately 1.43 g/cm3).
• The density of water is a standard value of 1 g/cm3 (or 1000 kg/m3).
• An object sinks in a fluid if its density is higher than the density of the fluid. Since 1.43 g/cm3 is greater than 1 g/cm3, the packet will definitely sink in water. Hence, the statement regarding sinking due to higher density is correct.
• The buoyant force (upthrust) acting on the packet is equal to the weight of the water displaced by the volume of the packet (350 cm3), which weighs 350 g. Since the actual weight of the packet (500 g) is more than the upthrust, it cannot float.

Additional Information

• Archimedes' Principle: This principle states that when a body is immersed fully or partially in a fluid, it experiences an upward force (buoyancy) that is equal to the weight of the fluid displaced by it.
• Conditions for Floating and Sinking:
• If Density of Object < Density of Fluid: The object will float.
• If Density of Object = Density of Fluid: The object will float while being fully submerged (neutral buoyancy).
• If Density of Object > Density of Fluid: The object will sink.
• Relative Density (Specific Gravity): It is the ratio of the density of a substance to the density of water. If the relative density is greater than 1, the substance will sink in water. For this packet, the relative density is 1.43.
• Mass vs. Weight: Mass is a measure of the amount of matter in an object (measured in grams or kilograms), whereas weight is the force exerted by gravity on that mass (measured in Newtons). In floatation problems, we often use mass and density for simplicity in CGS units (g/cm3).
• Applications: This concept is crucial in designing ships, submarines, and hot air balloons. A large iron ship floats because its average density (including the air inside) is less than that of water, even though iron itself is much denser.

Important Points

• Standard Values: The density of pure water is highest at 4 degrees Celsius, being exactly 1.00 g/cm3. Saltwater has a higher density (approx 1.025 g/cm3), which is why it is easier for humans to float in the ocean than in a freshwater pool.
• Numerical Fact: To find the mass of the water displaced by the packet, we multiply its volume (350 cm3) by the density of water (1 g/cm3), resulting in 350 g of water displaced.
• Misconception: An object does not sink just because it has a "high mass" or a "low volume"; it sinks because of the relationship (ratio) between mass and volume. A 1 kg block of wood will float, while a 10 g iron nail will sink.

The correct answer is The physiological activity of the cell.

Key Points

• The number of mitochondria per cell is not fixed and varies significantly depending on the physiological activity of the cell. This is because mitochondria are responsible for producing energy, and cells with higher energy demands require more of them. Hence, statement 4 is correct.
• Cells that are highly active metabolically, such as cardiac muscle cells, liver cells, and sperm cells, contain thousands of mitochondria to meet their continuous ATP (Adenosine Triphosphate) requirements.
• In contrast, cells with low metabolic activity, such as skin cells or certain connective tissue cells, have fewer mitochondria.

Some specialized cells, like mature mammalian red blood cells (RBCs), lack mitochondria entirely to maximize space for hemoglobin.

• The age of the organism may influence the efficiency or health of mitochondria, but it is not the primary determinant of the specific number of mitochondria found across different tissue types. Hence, statement 1 is incorrect.
• The size of the nucleus is a structural characteristic related to the amount of genetic material and cellular regulation, but it has no direct correlation with the quantity of mitochondria. Hence, statement 2 is incorrect.
• While mitochondria contain their own extranuclear DNA, the total amount of DNA present in a cell (predominantly nuclear DNA) does not dictate the number of mitochondrial organelles. Hence, statement 3 is incorrect.

Additional Information

• Structure of Mitochondria:
• Mitochondria are double-membrane-bound organelles. The outer membrane is smooth and porous, while the inner membrane is deeply folded into structures called cristae.
• The cristae increase the surface area available for chemical reactions, specifically the Electron Transport Chain (ETC), which is vital for ATP production.
• The internal compartment filled with fluid is known as the matrix, which contains enzymes for the Krebs cycle.
• Semi-Autonomous Nature:
• Mitochondria are considered semi-autonomous because they possess their own circular DNA and 70S ribosomes, allowing them to synthesize some of their own proteins.
• They reproduce independently within the cell through a process similar to bacterial division called binary fission.
• Functions:
• The primary function is aerobic respiration, earning them the title "Powerhouse of the cell".
• They also play roles in calcium storage, apoptosis (programmed cell death), and heat production (thermogenesis).

Important Points

• Discovery and Naming: Mitochondria were first observed by Albert von Kolliker in 1850 as granules in muscle cells. Richard Altmann described them as "bioblasts" in 1890, and the term "mitochondria" was officially coined by Carl Benda in 1898.
• Endosymbiotic Theory: This biological theory suggests that mitochondria originated from free-living prokaryotes (specifically proteobacteria) that entered into a symbiotic relationship inside a host eukaryotic cell billions of years ago.
• Mitochondrial DNA (mtDNA): Unlike nuclear DNA, mtDNA is inherited almost exclusively from the mother in humans, making it a crucial tool for tracing ancestry and studying evolutionary biology.

The correct answer is To supplement nitrogen and other nutrients.

Key Points

• Insectivorous plants, also known as carnivorous plants, have evolved to trap and digest insects because they typically grow in nutrient-poor soils, particularly those lacking in nitrogen.
• Nitrogen is a vital component for the synthesis of proteins, chlorophyll, and nucleic acids in plants. In environments like bogs, marshes, and swamps, the soil is often acidic and waterlogged, which prevents the decomposition of organic matter and makes nitrogen unavailable to plants.
• While these plants possess chlorophyll and are capable of photosynthesis to produce carbohydrates, they rely on animal prey to acquire essential minerals like nitrogen, phosphorus, and potassium that the soil cannot provide. Hence, statement 3 is correct.
• These plants do not trap insects to compete with herbivores for space; rather, they occupy ecological niches where other plant species struggle to survive due to mineral deficiencies. Hence, statement 1 is incorrect.
• They do not consume insects to take cellulose, as cellulose is a structural component of plant cell walls, not animal tissues; furthermore, plants synthesize their own cellulose. Hence, statement 2 is incorrect.
• Insectivorous plants often require bright sunlight for photosynthesis and are not specifically adapted to survive in low sunlight habitats through insect consumption. Hence, statement 4 is incorrect.

Additional Information

• Common Examples of Insectivorous Plants:
• Venus Flytrap (Dionaea muscipula): Native to the subtropical wetlands of the United States (North and South Carolina). It uses a snap trap mechanism triggered by sensitive trigger hairs.
• Pitcher Plant (Nepenthes & Sarracenia): Uses a pitfall trap. The leaves are modified into a jug-like structure filled with digestive liquor. Nepenthes khasiana is a species found in Meghalaya, India.
• Sundew (Drosera): These plants use flypaper traps. Their leaves are covered in tentacles that secrete a sticky, glistening substance called mucilage to ensnare prey.
• Bladderwort (Utricularia): These are aquatic or terrestrial plants that use suction traps (bladders) to capture small organisms like water fleas in freshwater habitats.
• Digestive Mechanism:
• Once an insect is trapped, the plant secretes digestive enzymes such as proteases, esterases, and acid phosphatases.
• These enzymes break down the animal's proteins and soft tissues into simple nitrogenous compounds (amino acids) and minerals, which are then absorbed by the leaf surfaces.

Important Points

• Partial Heterotrophs: Insectivorous plants are described as partial heterotrophs because they are autotrophic (produce their own food via photosynthesis) but heterotrophic for specific mineral requirements.
• Habitat Features: They are most commonly found in perennially wet areas with low pH (acidic). High acidity slows down the nitrifying bacteria that normally convert organic nitrogen into forms plants can use.
• Conservation: Many insectivorous plants are threatened or endangered due to habitat loss and illegal collection. For instance, the Pitcher Plant in India is protected under the Wildlife Protection Act.

The correct answer is Asexual reproduction is a regular source of variations in a population.

Key Points

• Variation refers to the differences that exist between individuals of the same species. These differences can be physical, physiological, or behavioral.
• Sexual reproduction is a significant source of variation because it involves the fusion of gametes from two different parents. Processes like crossing over during meiosis and the independent assortment of chromosomes ensure that offspring have a unique genetic makeup. Hence, statement 1 is correct.
• Due to these genetic reshufflings, individuals within a population are unique.

No two individuals (except identical twins) are exactly alike, which helps the population adapt to changing environments. Hence, statement 2 is correct.

• Variation also arises due to inaccuracy in the copying of DNA during cell division. Although DNA replication is highly precise, biochemical processes are not 100% foolproof, and small changes in the DNA sequence (mutations) introduce new variations. Hence, statement 3 is correct.
• Asexual reproduction generally involves a single parent and occurs through mitosis. The offspring produced are genetically identical to the parent and are referred to as clones. Therefore, it is not a regular source of variation; variation in asexual organisms only occurs through rare random mutations. Hence, statement 4 is incorrect.
• Hence, the correct answer is Asexual reproduction is a regular source of variations in a population.

Additional Information

• Importance of Variation:
• Variation is the raw material for Evolution. Without variation, Natural Selection would have no diverse traits to act upon.
• It increases the survival chances of a species during environmental stressors such as climate change, diseases, or predation.
• Types of Variations:
• Somatic Variations: These occur in the non-reproductive cells and are not inherited by the next generation. They are often caused by environmental factors.
• Germinal Variations: These occur in the germ cells (sperm or egg) and are heritable. These are the variations that drive evolutionary changes over generations.
• Mechanisms of Variation in Plants:
• In plants, variations can be observed in leaf shape, flower color, height, and seed texture.
• Polyploidy, which is the possession of more than two complete sets of chromosomes, is a common source of variation and speciation in the plant kingdom.

Important Points

• DNA Copying: The process of DNA replication uses enzymes like DNA polymerase. While there are proofreading mechanisms, the inherent chemical nature of the process leads to occasional "errors," which are the fundamental source of all genetic diversity.
• Clones in Asexual Reproduction: Plants using methods like vegetative propagation (runners, tubers, bulbs) produce offspring that are genetically identical. This is advantageous in stable environments but risky if the environment changes suddenly, as the entire population may be susceptible to the same threat.
• Recombination: This occurs during Prophase I of meiosis when homologous chromosomes exchange segments. This specific mechanism is why siblings from the same parents look different.

p data-end="57" data-start="0">The correct answer is Copper.

 

Key Points

• Copper is a metal that does not react with dilute hydrochloric acid (HCl) under normal conditions. This is because Copper is placed below hydrogen in the reactivity series of metals.
• In a reaction between a metal and a dilute acid, the metal must displace hydrogen from the acid to form a metal salt and release hydrogen gas. Since Copper is less reactive than hydrogen, it cannot lose electrons to the hydrogen ions (H+) present in the acid. Hence, option 1 is correct.
• Zinc is more reactive than hydrogen and sits higher in the activity series. When it comes into contact with dilute HCl, it reacts steadily to form Zinc Chloride (ZnCl2) and evolves hydrogen gas. Hence, option 2 is incorrect.
• Aluminium is a highly reactive metal. Although it often has a protective Aluminium Oxide layer, once that layer is bypassed, it reacts vigorously with dilute HCl to produce Aluminium Chloride (AlCl3) and hydrogen gas. Hence, option 3 is incorrect.
• Iron is also positioned above hydrogen in the reactivity series. It reacts slowly with dilute hydrochloric acid at room temperature to form Ferrous Chloride (FeCl2) and hydrogen gas. Hence, option 4 is incorrect.

Additional Information

• The Reactivity Series: This is a series of metals arranged in the decreasing order of their reactivity. Metals like Potassium (K), Sodium (Na), and Calcium (Ca) are at the top, while Gold (Au) and Platinum (Pt) are at the bottom. Metals above hydrogen can displace it from dilute acids, while those below it (Copper, Mercury, Silver, Gold) cannot.
• Reaction with Nitric Acid: While Copper does not react with dilute HCl, it can react with Nitric Acid (HNO3). However, this is not a simple displacement reaction; because Nitric Acid is a strong oxidizing agent, it oxidizes the metal, and instead of hydrogen gas, oxides of nitrogen (like NO or NO2) are evolved.
• Aqua Regia: Noble metals like Gold and Platinum do not react even with concentrated HCl or Nitric acid individually. They only dissolve in Aqua Regia, which is a freshly prepared mixture of concentrated Hydrochloric acid and concentrated Nitric acid in a 3:1 ratio.
• Physical Properties of Copper: It is a reddish-brown transition metal with the atomic number 29. It is widely used in electrical wiring due to its high electrical conductivity and in alloying to create Brass and Bronze.
• Hydrogen Gas Test: When metals above hydrogen react with dilute HCl, the evolved hydrogen gas can be tested using a burning splinter, which extinguishes with a characteristic "pop" sound.

Important Points

• Aluminium's Passivity: Sometimes Aluminium appears to not react immediately with acids. This is due to a thin, tough layer of Aluminium Oxide (Al2O3) on its surface. Once the acid dissolves this layer, the exothermic reaction proceeds rapidly.
• Chemical Equations:
• Zinc: Zn + 2HCl → ZnCl2 + H2
• Iron: Fe + 2HCl → FeCl2 + H2
• Aluminium: 2Al + 6HCl → 2AlCl3 + 3H2
• Copper: Cu + HCl → No Reaction
• Standard Reduction Potential: From an electrochemical perspective, metals with a negative reduction potential (like Zinc and Iron) can displace hydrogen, whereas metals with a positive reduction potential (like Copper, +0.34V) cannot.

The correct answer is It melts and may later evaporate.

Key Points

• When a solid is heated, the thermal energy is absorbed by its particles, which increases their kinetic energy. As the particles gain energy, they vibrate more vigorously around their fixed positions.
• As heating continues, the substance reaches its Melting Point. At this specific temperature, the energy supplied is used to break the intermolecular forces of attraction that hold the particles in a rigid lattice structure.
• The process of a solid changing into a liquid is known as Fusion or Melting. During this phase change, the temperature remains constant even though heat is still being added; this heat is known as the Latent Heat of Fusion.
• Once the entire solid has turned into a liquid, further heating will cause the temperature of the liquid to rise. The particles in the liquid move faster and more freely.
• Eventually, the liquid reaches its Boiling Point, where the particles gain enough energy to completely overcome the remaining attractive forces and transition into the gaseous state through evaporation or boiling. Hence, the correct progression is that the solid melts and may later evaporate.

Additional Information

• States of Matter:
• Solid: Particles are packed closely together in a regular pattern with very low kinetic energy and high intermolecular attraction. They have a fixed shape and fixed volume.
• Liquid: Particles are close together but can slide past each other. They have a fixed volume but no fixed shape, taking the shape of the container.
• Gas: Particles are far apart and move randomly at high speeds. They have no fixed shape and no fixed volume, expanding to fill any space available.
• Thermal Expansion: Most solids undergo expansion when heated before they reach their melting point. This occurs because the increased vibration of particles increases the average distance between them, causing the overall volume of the solid to increase slightly.
• Phase Transitions:
• Sublimation: A rare process where a solid turns directly into a gas without passing through the liquid phase. Examples include Dry Ice (Solid Carbon Dioxide), Naphthalene, and Camphor.
• Vaporization: The transition from liquid to gas. This includes Evaporation (which occurs at the surface below the boiling point) and Boiling (which occurs throughout the bulk of the liquid at a specific temperature).

Important Points

• Latent Heat: This is the "hidden" heat absorbed or released by a substance during a change in its physical state (phase) that occurs without changing its temperature.
• Latent Heat of Fusion: For water, this value is approximately 334 Joules per gram at 0 degrees Celsius.
• Latent Heat of Vaporization: For water, this value is approximately 2260 Joules per gram at 100 degrees Celsius.
• Intermolecular Forces: The strength of these forces determines the Melting Point and Boiling Point of a substance. Substances with stronger bonds (like ionic solids) require more energy (higher temperatures) to melt compared to those with weaker bonds (like molecular solids).
• Kinetic Molecular Theory: This theory explains that temperature is a direct measurement of the average kinetic energy of the particles in a substance. Therefore, continuous heating is synonymous with increasing the energy of the constituent particles.

The correct answer is A-2; B-1; C-3; D-4.

Key Points

• Acids and Hydrogen Ions (A-2): According to the Arrhenius theory, an acid is a substance that dissociates in water to yield hydrogen ions (H+). Since H+ ions cannot exist alone, they combine with water molecules to form hydronium ions (H3O+). Hence, A matches with 2 is correct.
• Bases and Hydroxide Ions (B-1): A base is defined as a substance that, when dissolved in water, increases the concentration of hydroxide ions (OH-). Bases that are soluble in water are specifically called alkalis. Hence, B matches with 1 is correct.
• Neutralization Reaction (C-3): When an acid reacts with a base, the H+ ions of the acid react with the OH- ions of the base to form water (H2O) and a salt. This chemical reaction is known as Neutralization and is typically exothermic in nature. Hence, C matches with 3 is correct.
• Electrical Conductivity (D-4): Both acids and bases in their aqueous solutions are capable of conducting electricity. This conductivity is attributed to the presence of free ions (cations and anions) in the solution, which act as charge carriers. Pure distilled water does not conduct electricity, but the addition of an acid or base provides the necessary electrolytes. Hence, D matches with 4 is correct.
• Hence, the correct answer is A-2; B-1; C-3; D-4.

Additional Information

• Characteristics of Acids:
• Acids have a sour taste and turn blue litmus paper red.
• They have a pH value of less than 7 on the pH scale.
• Common examples include Hydrochloric acid (HCl), Sulphuric acid (H2SO4), and Citric acid found in lemons.
• Strong acids like HCl ionize completely in water, while weak acids like acetic acid (vinegar) ionize only partially.
• Characteristics of Bases:
• Bases have a bitter taste and a soapy or slippery feel to the touch.
• They turn red litmus paper blue and have a pH value of greater than 7.
• Common examples include Sodium hydroxide (NaOH), Calcium hydroxide (Ca(OH)2), and Potassium hydroxide (KOH).
• Bases are used extensively in the manufacture of soaps, detergents, and antacids.
• The pH Scale:
• The pH scale was introduced by S.P.L. Sorensen in 1909 to measure the acidity or alkalinity of a solution.
• The scale ranges from 0 to 14, where 7 is neutral (the pH of pure water).
• A lower pH signifies a higher concentration of hydrogen ions, making the solution more acidic.

Important Points

• Indicators: Substances like Phenolphthalein and Methyl Orange are used to test for acids and bases. Phenolphthalein remains colorless in acid but turns pink in basic solutions.
• Universal Indicator: This is a mixture of several indicators that shows different colors at different concentrations of hydrogen ions in a solution, helping determine the approximate pH value.
• Strength of Solutions: The strength of an acid or base depends on the number of H+ ions or OH- ions produced, respectively. For instance, 1 Molar HCl is a stronger acid than 1 Molar CH3COOH because it produces more H+ ions.

The correct answer is Momentum has both magnitude and direction.

Key Points

• Momentum is a fundamental concept in physics, defined as the product of an object's mass and its velocity. It is typically represented by the symbol p.
• Statement 1: Momentum is a vector quantity. By definition, a vector quantity is one that has both a magnitude (how much) and a direction (where it is going). The direction of the momentum vector is the same as the direction of the velocity vector. Hence, statement 1 is correct.
• Statement 2: The Standard International (SI) unit of momentum is the kilogram-meter per second, written as kg·m/s. The statement claims the unit is kilogram per second, which is incorrect as it lacks the meter (distance) component required for velocity. Hence, statement 2 is incorrect.
• Statement 3: Mathematically, momentum is calculated as p = m × v, where m is mass and v is velocity. It is the product of these two variables, not the sum. Hence, statement 3 is incorrect.
• Statement 4: Since momentum is derived from velocity (which is a vector), it must have a direction.

Only scalar quantities, such as speed or mass, have magnitude only. Hence, statement 4 is incorrect.

Additional Information

• Conservation of Momentum: This is a major law of physics stating that the total momentum of an isolated system remains constant if no external forces act on it. This principle is vital in analyzing collisions and explosions.
• Newton's Second Law of Motion: Sir Isaac Newton originally defined his second law in terms of momentum. He stated that the force (F) acting on an object is equal to the rate of change of momentum (dp/dt) over time.
• Impulse: The change in momentum is known as impulse. It is the product of the average force and the time interval during which it acts. The units for impulse are Newton-seconds (N·s), which are equivalent to kg·m/s.
• Relativistic Momentum: In Einstein’s theory of special relativity, as an object's speed approaches the speed of light, its momentum increases more rapidly than its velocity, requiring a modified formula that includes the Lorentz factor.

Important Points

• Dimensional Formula: The dimensional representation of momentum is [MLT⁻¹], where M is Mass, L is Length, and T is Time.
• Mass vs. Velocity Influence: A very heavy object (like a ship) moving slowly can have the same momentum as a light object (like a bullet) moving very fast.
• Practical Application: Safety features in vehicles, such as airbags and crumple zones, are designed to increase the time it takes for momentum to change during a crash, thereby reducing the impact force on the passengers.
• CGS Unit: In the Centimetre-Gram-Second system, the unit of momentum is the gram-centimetre per second (g·cm/s).

The correct answer is Fossilisation of plants and animals under high temperature and pressure over millions of years.

Key Points

• Fossil fuels like coal and petroleum are formed through the biological and chemical transformation of ancient organic matter.
• Coal primarily originates from the remains of terrestrial plants and trees that grew in vast swampy forests approximately 300 to 360 million years ago during the Carboniferous Period. When these plants died, they were buried under layers of water and dirt, preventing full decay. Hence, statement 4 is the most accurate explanation.
• Petroleum (crude oil) and natural gas are derived from the remains of microscopic marine organisms, such as plankton and algae. These organisms settled on the ocean floor and were covered by sediments like silt and mud.
• The transformation process requires anaerobic conditions (absence of oxygen), which ensures that the organic matter does not rot completely but undergoes slow chemical changes.
• Over millions of years, the weight of the accumulating sediment layers creates high pressure and generates high temperature from the Earth's interior, which eventually converts the buried organic debris into hydrocarbons.

Additional Information

• Classification of Coal: Based on the degree of compression and carbon content, coal is divided into four main types: Peat (lowest carbon), Lignite (brown coal), Bituminous (most common), and Anthracite (hardest coal with over 85% carbon).
• Petroleum Refining: Crude oil extracted from the ground is a mixture of various hydrocarbons. It is processed in refineries using fractional distillation to produce petrol, diesel, kerosene, asphalt, and liquefied petroleum gas (LPG).
• Non-Renewable Resources: Because the formation of these fuels takes millions of years, they are classified as non-renewable energy sources. Their current rate of consumption far exceeds the rate of natural replenishment.
• Environmental Impact: The combustion of fossil fuels releases carbon dioxide (CO2), sulfur dioxide, and nitrogen oxides, which contribute to the greenhouse effect and global warming.

Important Points

• Carbonisation: The slow chemical process of conversion of dead vegetation into coal is specifically known as carbonisation. This happens under conditions of extreme pressure and lack of air.
• Oil Windows: Petroleum formation typically occurs within a specific temperature range called the "oil window" (usually 50°C to 150°C). If the temperature is higher, the organic matter is further broken down into natural gas (methane).
• Geological Traps: Petroleum is often found trapped in porous reservoir rocks (like sandstone or limestone) situated beneath an impermeable cap rock (like shale or salt) that prevents the oil from escaping to the surface.

The correct answer is Electrolytic reduction of their molten chlorides or oxides.

Key Points

• Metals located at the top of the reactivity series, such as Sodium (Na), Magnesium (Mg), Calcium (Ca), and Aluminium (Al), are highly reactive and never found in nature as free elements.
• These metals cannot be reduced by carbon or carbon monoxide because they have a much higher affinity for oxygen than carbon does. Consequently, carbon cannot pull oxygen away from these metal oxides. Hence, statement 4 is incorrect.
• To extract these highly electropositive metals, the process of electrolytic reduction is employed. This involves passing an electric current through the molten (liquid) state of their chlorides or oxides. Hence, statement 3 is correct.
• During the electrolysis of molten sodium chloride (NaCl), the sodium metal is deposited at the cathode (the negatively charged electrode), while chlorine gas is liberated at the anode (the positively charged electrode).
• In the case of Aluminium, it is extracted from its molten oxide (Alumina - Al2O3) using the Hall-Héroult process, where cryolite is often added to lower the melting point and increase conductivity.

Additional Information

• Roasting:
• This is the process of heating sulphide ores strongly in the presence of excess air to convert them into metal oxides.
• It is typically used for metals of medium reactivity like Zinc (Zn) and Mercury (Hg). For example, Cinnabar (HgS) is roasted to obtain mercury. Hence, statement 1 is incorrect in this context.
• Calcination:
• This involves heating carbonate ores strongly in the absence or limited supply of air to turn them into oxides.
• An example is the calcination of Zinc Carbonate (ZnCO3) to produce Zinc Oxide (ZnO). This method is used for ores found as carbonates in the middle of the reactivity series. Hence, statement 2 is incorrect in this context.
• Reduction with Carbon:
• Metals of moderate reactivity, such as Iron (Fe), Zinc (Zn), Lead (Pb), and Tin (Sn), are extracted by reducing their oxides with coke (carbon) in a furnace.
• In a Blast Furnace, Haematite (Fe2O3) is reduced by carbon/carbon monoxide to produce molten iron.
• Reactivity Series Overview:
• High Reactivity (K, Na, Ca, Mg, Al): Extracted by Electrolysis.
• Medium Reactivity (Zn, Fe, Pb, Cu): Extracted by Reduction using Carbon after roasting/calcination.
• Low Reactivity (Ag, Au): Found in native/free state; Mercury (Hg) is extracted by simple heating of its ore.

Important Points

• The Reactivity Series is an arrangement of metals in descending order of their chemical reactivity. Potassium (K) is at the top, while Gold (Au) is at the bottom.
• Electrolytic refining is a different process used for purifying impure metals like Copper (Cu) and Gold (Au) after they have been extracted by other chemical methods.
• For Aluminium extraction, the molten mixture of Alumina and Cryolite (Na3AlF6) is electrolyzed at approximately 950°C to 1000°C.
• The choice of extraction method is purely determined by the position of the metal in the activity series and the chemical nature of its ore.

The correct answer is It has a focal length of 1 metre..

Key Points

• The power of a lens is defined as the ability of a lens to converge or diverge light rays. Mathematically, it is the reciprocal of its focal length.
• The SI unit of power of a lens is the dioptre, which is denoted by the symbol D.
• The relationship between power (P) and focal length (f) is given by the formula P = 1/f, where the focal length must be measured in metres.
• By definition, 1 dioptre is the power of a lens whose focal length is 1 metre (1 D = 1 m⁻¹). Hence, the statement in the question indicates a focal length of 1 metre. Hence, the correct answer is option 2.
• The power of a lens is positive for a converging (convex) lens and negative for a diverging (concave) lens.

Additional Information

• Focal Length (f):
• It is the distance between the optical centre of the lens and the principal focus.
• If the focal length is given in centimetres, the power formula is modified to P = 100/f (in cm). For example, a lens with a focal length of 25 cm has a power of +4 D.
• Sign Convention and Lens Types:
• A convex lens has a real focus and thus a positive focal length, leading to a positive power.
• A concave lens has a virtual focus and a negative focal length, resulting in a negative power.
• Power of a Combination of Lenses:
• When two or more thin lenses are placed in contact, the total power (P) of the system is the algebraic sum of the individual powers: P = P1 + P2 + P3 + ....
• This principle is used by optometrists to design corrective spectacles and by engineers in telescopes and microscope objectives.
• Magnification (m):
• Unlike power, magnification is the ratio of the height of the image to the height of the object (m = h'/h) or the ratio of image distance to object distance (m = v/u).
• It is a unitless quantity, whereas power has the unit of m⁻¹ or dioptre.

Important Points

• Corrective Lenses: A person suffering from Myopia (nearsightedness) is prescribed a lens with negative power (concave), while someone with Hypermetropia (farsightedness) requires a lens with positive power (convex).
• Optical Instruments: The use of dioptre helps in the standardized manufacturing of eye-glasses and contact lenses globally. The least distance of distinct vision for a normal human eye is approximately 25 cm.
• Refractive Index: The power of a lens also depends on the refractive index of the material it is made of and the radii of curvature of its surfaces, as described by the Lens Maker's Formula.

The correct answer is P = I × R².

Key Points

• Electric Power (P) is defined as the rate at which electrical energy is consumed or dissipated in an electric circuit. It is the rate of doing work.
• The fundamental expression for Electric Power is the product of Potential Difference (V) and Current (I), represented as P = V × I. Hence, statement 1 is correct.
• According to Ohm's Law, the relationship between voltage, current, and resistance is given by V = I × R. By substituting V in the power formula (P = VI), we get P = (I × R) × I, which results in P = I² × R. Hence, statement 2 is correct.
• Using Ohm's Law again, we can express current as I = V / R. By substituting I in the fundamental power formula (P = VI), we get P = V × (V / R), which results in P = V² / R. Hence, statement 4 is correct.
• The expression P = I × R² does not follow from any physical derivation of electrical laws and is dimensionally inconsistent with the units of power. Hence, statement 3 is incorrect.
• Therefore, P = I × R² is NOT a correct expression for electric power.

Additional Information

• SI Unit of Power: The SI unit of electric power is the Watt (W). It is named after the Scottish inventor James Watt. 1 Watt is defined as the power consumed by a device when 1 Ampere of current flows through it at a potential difference of 1 Volt.
• Ohm's Law: Proposed by Georg Simon Ohm in 1827, it states that the current flowing through a conductor is directly proportional to the voltage across it, provided physical conditions like temperature remain constant (V = IR).
• Components of the Formula:
• V stands for Voltage or Potential Difference, measured in Volts (V).
• I stands for Electric Current, measured in Amperes (A).
• R stands for Resistance, measured in Ohms (Ω).
• Commercial Unit of Energy: While the SI unit of energy is the Joule (J), the commercial unit is the Kilowatt-hour (kWh). 1 kWh is the energy consumed by an appliance of 1000 Watts in one hour. Numerically, 1 kWh = 3.6 × 10⁶ Joules.

Important Points

• Joule's Law of Heating: This law states that the heat produced in a resistor is directly proportional to the square of the current, the resistance, and the time for which the current flows (H = I²Rt). This is directly related to the power formula P = I²R.
• Power in Series vs. Parallel:
• In a series circuit, the current (I) remains constant. Thus, P = I²R is more convenient for calculations, showing power is directly proportional to resistance.
• In a parallel circuit, the voltage (V) remains constant. Thus, P = V² / R is more convenient, showing power is inversely proportional to resistance.
• Practical Applications: These formulas are used to determine the power rating of household appliances like bulbs, heaters, and irons. For example, a bulb rated 100W, 220V uses these relations to define its operational resistance.

The correct answer is negative.

Key Points

• The work done by a force on an object is defined as the product of the component of the force in the direction of the displacement and the magnitude of the displacement.
• Mathematically, work is expressed as W = F × d × cosθ, where F is the force magnitude, d is the displacement, and θ is the angle between the force vector and the displacement vector.
• Friction is a force that resists the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
• When an object moves on a surface, kinetic friction acts in a direction opposite to the direction of the object's displacement.
• Because the force of friction and the displacement are in opposite directions, the angle θ is 180 degrees.
• Since the cosine of 180 degrees is -1, the resulting value of work is negative. Hence, the correct answer is negative.

Additional Information

• Types of Work:
• Positive Work: Occurs when the force and displacement are in the same direction (angle between 0 and 90 degrees). For example, work done by a person pulling a cart.
• Negative Work: Occurs when the force and displacement are in opposite directions (angle between 90 and 180 degrees). Friction is the most common example.
• Zero Work: Occurs when the force is perpendicular to the displacement (angle is 90 degrees) or if the displacement is zero. For instance, the centripetal force acting on a satellite does zero work because it is perpendicular to the motion.
• Nature of Friction:
• Friction is a non-conservative force, meaning the work done against it depends on the path taken rather than just the initial and final positions.
• The coefficient of friction (represented by the Greek letter μ) is a dimensionless scalar value that describes the ratio of the force of friction between two bodies and the normal force pressing them together.
• In almost all practical mechanical systems, friction converts kinetic energy into thermal energy (heat), leading to energy dissipation.

Important Points

• While work done by friction is usually negative, it can be positive in certain frames of reference or specific scenarios. For example, if a block A is placed on top of block B and block B is accelerated, the friction exerted by B on A causes A to move. In this case, friction does positive work on block A because the force and displacement are in the same direction.
• The S.I. unit of work is the Joule (J), which is equivalent to 1 Newton-meter (N·m).
• The Work-Energy Theorem states that the net work done on an object is equal to the change in its kinetic energy. Since friction usually does negative work, it typically decreases the kinetic energy of a moving object, causing it to slow down.

The correct answer is Synapse.

Key Points

• A Synapse is a functional junction between two neurons (nerve cells) or between a neuron and an effector organ, such as a muscle or gland.
• The actual physical gap between the membranes of the two communicating neurons is specifically known as the synaptic cleft, which typically measures about 20 to 40 nanometers in width.
• Information is transmitted across this gap through the release of signaling molecules called neurotransmitters, which bridge the distance between the presynaptic and postsynaptic cells.
• The concept of the synapse was first introduced and named by the Nobel Prize-winning physiologist Sir Charles Sherrington in 1897.
• This structure is vital for the unidirectional flow of nerve impulses, ensuring that signals travel from the axon terminal of one neuron toward the dendrites or cell body of the next.

Additional Information

• Chemical Synapses:
• These are the most common type of synapses in the human nervous system.
• When an electrical impulse (action potential) reaches the end of an axon, it triggers the influx of calcium ions.
• This causes synaptic vesicles to fuse with the membrane and release neurotransmitters like acetylcholine, dopamine, or serotonin into the cleft.
• Electrical Synapses:
• In these synapses, the membranes of the two neurons are very close together, connected by special proteins called gap junctions.
• Electrical current flows directly from one cell to another, making transmission much faster than chemical synapses. They are common in the heart and smooth muscle where synchronized contraction is required.
• Synaptic Plasticity:
• This refers to the ability of synapses to strengthen or weaken over time in response to increases or decreases in their activity.
• It is the fundamental biological basis for learning and memory in the brain.

Important Points

• Stroma: In biology, this term refers to the supportive, connective tissue framework of an organ (like the ovary or kidney) or the fluid-filled space surrounding the thylakoids inside a chloroplast. Hence, option 1 is incorrect.
• Intermembrane space: This is the region between the inner and outer membranes of a double-membrane organelle, such as mitochondria or chloroplasts. It plays a key role in oxidative phosphorylation. Hence, option 3 is incorrect.
• Lumen: This refers to the inside space of a tubular structure or a hollow organ, such as the interior of an artery, the small intestine, or the endoplasmic reticulum. Hence, option 4 is incorrect.
• A single neuron can have anywhere from 1,000 to 10,000 synapses, allowing for a massive network of trillions of connections within the human brain.

The correct answer is capillaries; gases.

Key Points

• The alveoli are the functional units of the respiratory system where the actual process of gas exchange occurs between the lungs and the blood.
• Each alveolus is wrapped in a dense, mesh-like network of capillaries, which are the smallest and thinnest blood vessels in the human body.
• The primary function of this structural arrangement is to facilitate the exchange of gases, specifically oxygen (O2) and carbon dioxide (CO2), through the process of diffusion.
• The walls of both the alveoli and the capillaries are composed of a single layer of epithelial cells, making them extremely thin (about 0.5 micrometers) to allow gases to pass through easily.
• During inhalation, oxygen moves from the alveoli into the capillaries to be carried to the rest of the body, while carbon dioxide moves from the capillaries into the alveoli to be exhaled.

Additional Information

• Surface Area for Gas Exchange: The human lungs contain approximately 300 to 500 million alveoli. If spread out, they would cover a surface area of about 70 to 100 square meters, which is roughly the size of a tennis court.
• Diffusion Gradient: The movement of gases is driven by partial pressure differences. Oxygen pressure is higher in the alveoli than in the deoxygenated blood within the capillaries, causing it to flow inward.
• Role of Hemoglobin: Once oxygen diffuses into the capillaries, it binds to hemoglobin molecules inside red blood cells (RBCs) for transport to various tissues and organs.
• Blood Flow Direction: Deoxygenated blood reaches the capillaries via the pulmonary artery from the right ventricle of the heart, and oxygenated blood returns to the left atrium via the pulmonary vein.
• Respiratory Membrane: The combination of the alveolar wall and the capillary wall is often referred to as the respiratory membrane or the blood-air barrier.

Important Points

• Pulmonary Surfactant: The alveoli are lined with a lipoprotein substance called surfactant, which reduces surface tension and prevents the tiny air sacs from collapsing during exhalation.
• Mechanism of Action: The exchange of gases is a purely passive process, meaning it does not require cellular energy (ATP) to occur.
• Effect of Diseases: Conditions such as emphysema (often caused by smoking) lead to the destruction of alveolar walls, significantly reducing the surface area available for gas exchange and causing shortness of breath.
• Capillary Transit Time: Under normal resting conditions, a red blood cell spends about 0.75 seconds in the pulmonary capillaries, which is more than enough time for oxygen saturation to reach 100%.

The correct answer is TT × tt.

Key Points

• A cross between TT (homozygous dominant) and tt (homozygous recessive) results in all offspring having the genotype Tt. This means 100% of the F1 generation will be heterozygous. Hence, statement 3 is correct.
• In the cross tt × tt, both parents are homozygous recessive. They can only pass the t allele to their offspring, resulting in 100% homozygous recessive (tt) individuals. Hence, statement 1 is incorrect.
• In the cross TT × TT, both parents are homozygous dominant. They can only pass the T allele to their offspring, resulting in 100% homozygous dominant (TT) individuals. Hence, statement 2 is incorrect.
• In the cross Tt × Tt, both parents are heterozygous. According to Mendelian genetics, this cross produces a genotypic ratio of 1:2:1 (25% TT, 50% Tt, and 25% tt). Since only 50% are heterozygous, they are not "all" heterozygous. Hence, statement 4 is incorrect.
• This principle was first established by Gregor Mendel in his 1865 experiments with pea plants (Pisum sativum), forming the basis of the Law of Segregation.

Additional Information

• Heterozygous: This refers to an individual having two different alleles for a particular gene, such as Tt. In such cases, the dominant allele (T) typically masks the expression of the recessive allele (t).
• Homozygous: This term describes an organism that has two identical alleles for a trait, which can be either homozygous dominant (TT) or homozygous recessive (tt).
• Genotype and Phenotype: The genotype is the actual genetic makeup (e.g., Tt), while the phenotype is the observable physical characteristic (e.g., Tall height). In an F1 generation of Tt, the phenotype is usually 100% dominant.
• Punnett Square: This is a graphical representation used to calculate the probability of an offspring having a particular genotype. It was devised by Reginald Punnett in 1905.
• Monohybrid Cross: This is a genetic cross between two individuals involving one pair of contrasting characters. The cross of TT × tt is a classic example of a monohybrid cross looking at plant height.

Important Points

• Law of Dominance: Gregor Mendel observed that in the F1 generation, only one of the parental traits (the dominant one) appears. For the cross TT × tt, although the offspring are heterozygous, they all appear Tall.
• Pure-breeding Strains: The organisms TT and tt are considered pure-breeding or true-breeding because when self-pollinated, they always produce offspring with the same trait. Crossing two different true-breeding parents is the only way to ensure 100% heterozygosity in the first generation.
• Numerical Ratios: In the F2 generation (produced by crossing Tt × Tt), the phenotypic ratio is 3:1, while the genotypic ratio is 1:2:1.