Q1. The following is a list of the components of a chemical synapse. A mutation in the structure of which of these would affect only the reception of the message, not its release or the response?
Correct Answer: (a)
Membrane proteins on the postsynaptic cell include the receptors that specifically bind to neurotransmitters. A mutation here would specifically block the 'reception' of the chemical signal from the cleft, without preventing the presynaptic cell from releasing the neurotransmitter or the postsynaptic cell from responding internally once a signal is received.
Membrane proteins on the postsynaptic cell include the receptors that specifically bind to neurotransmitters. A mutation here would specifically block the 'reception' of the chemical signal from the cleft, without preventing the presynaptic cell from releasing the neurotransmitter or the postsynaptic cell from responding internally once a signal is received.
Q2. Arrange the following ecosystems in increasing order of mean NPP (Tonnes / ha / year)
A. Tropical deciduous forest
B. Temperate coniferous forest
C. Tropical rain forest
D. Temperate deciduous forest
A. Tropical deciduous forest
B. Temperate coniferous forest
C. Tropical rain forest
D. Temperate deciduous forest
Correct Answer: (d)
Productivity typically follows the order: Temperate Coniferous (B) < Temperate Deciduous (D) < Tropical Deciduous (A) < Tropical Rain Forest (C).
Productivity typically follows the order: Temperate Coniferous (B) < Temperate Deciduous (D) < Tropical Deciduous (A) < Tropical Rain Forest (C).
Q3. Which one of the following acts as the “alarm signal” to activate the body’s adaptive immune system by stimulating helper T cells?
Correct Answer: (b)
Interleukin-1 is a cytokine released by macrophages and antigen-presenting cells. It functions as an alarm signal by activating helper T cells, thereby linking innate immunity to adaptive immunity.
Interleukin-1 is a cytokine released by macrophages and antigen-presenting cells. It functions as an alarm signal by activating helper T cells, thereby linking innate immunity to adaptive immunity.
Q4. In a chloroplast, the highest number of protons are found in
Correct Answer: (b)
During light reactions, protons are actively pumped into the thylakoid lumen, making it the area with the highest concentration and lowest pH.
During light reactions, protons are actively pumped into the thylakoid lumen, making it the area with the highest concentration and lowest pH.
Q5. Keeping in view the fluid mosaic model for the structure of cell membrane, which one of the following statements is correct with respect to the movement of lipids and proteins from one lipid monolayer to the other (described as flipflop movement)?
Correct Answer: (b)
Lipid molecules can rarely flip-flop across the membrane bilayer, but proteins, being very large and polar in specific regions, are unable to flip.
Lipid molecules can rarely flip-flop across the membrane bilayer, but proteins, being very large and polar in specific regions, are unable to flip.
Q6. Match the items given in column-I with their role given in column-II and choose the correct option.
| Column-I | Column-II |
|---|---|
| A. SER | I. Increase the surface area |
| B. Golgi apparatus | II. Store oils or fats |
| C. Cristae | III. Excretion |
| D. Peroxisome | IV. Photorespiration |
| E. Elaioplasts | V. Synthesis of lipid |
Correct Answer: (a)
SER: lipids; Golgi: (lysosomes/excretion link); Cristae: surface area; Peroxisome: photorespiration; Elaioplasts: oils.
SER: lipids; Golgi: (lysosomes/excretion link); Cristae: surface area; Peroxisome: photorespiration; Elaioplasts: oils.
Q7. FISH analysis of a breast tumor biopsy for HER2 gene reveals two spots of fluorescence in cells. What conclusion do these data support about the tumor?
Correct Answer: (d)
Fluorescence In Situ Hybridization (FISH) is used to visualize specific DNA sequences. Normal diploid cells have two copies of every gene. Since the analysis shows only two spots of fluorescence, the HER2 gene has not been duplicated or amplified. Because targeted therapies like Herceptin are only effective in tumors where the gene is amplified and overexpressing protein, these treatments would not be suitable for this patient.
Fluorescence In Situ Hybridization (FISH) is used to visualize specific DNA sequences. Normal diploid cells have two copies of every gene. Since the analysis shows only two spots of fluorescence, the HER2 gene has not been duplicated or amplified. Because targeted therapies like Herceptin are only effective in tumors where the gene is amplified and overexpressing protein, these treatments would not be suitable for this patient.
Q8. Which hormone is secreted only during pregnancy in women?
Correct Answer: (c)
hCG, hPL and relaxin are produced in women only during pregnancy.
hCG, hPL and relaxin are produced in women only during pregnancy.
Q9. Identify the wrong statement about meiosis
Correct Answer: (d)
Meiosis involves two cycles of nuclear division but only a single cycle of DNA replication.
Meiosis involves two cycles of nuclear division but only a single cycle of DNA replication.
Q10. Match the following column I with column II.
| Column - I | Column - II |
|---|---|
| A. Carcinogen | I. Tumour |
| B. Anaphase-I | II. Disjunction |
| C. Mitosis | III. Synapse |
| D. Zygotene | IV. Plectonemic coiling |
Correct Answer: (a)
Carcinogens cause tumors. Anaphase I involves disjunction. Mitosis shows plectonemic coiling (tight twisting). Zygotene involves synapse.
Carcinogens cause tumors. Anaphase I involves disjunction. Mitosis shows plectonemic coiling (tight twisting). Zygotene involves synapse.
Q11. Which one of the following is not used for construction of ecological pyramids?
Correct Answer: (c)
Ecological pyramids are built based on numbers, energy, or biomass. For biomass, dry weight is preferred over fresh weight because fresh weight varies with water content.
Ecological pyramids are built based on numbers, energy, or biomass. For biomass, dry weight is preferred over fresh weight because fresh weight varies with water content.
Q12. The shoot tip of an emerging maize seedling is protected by
Correct Answer: (c)
In monocots like maize, the emerging shoot (plumule) is encased in a protective sheath called the coleoptile, which pushes through the soil.
In monocots like maize, the emerging shoot (plumule) is encased in a protective sheath called the coleoptile, which pushes through the soil.
Q13. When you take a deep breath, your stomach moves out because
Correct Answer: (d)
The diaphragm is a dome-shaped muscle separating the thoracic and abdominal cavities. When it contracts, it flattens and moves downward to increase the volume of the lungs. This downward movement displaces the abdominal organs, causing the stomach area to protrude.
The diaphragm is a dome-shaped muscle separating the thoracic and abdominal cavities. When it contracts, it flattens and moves downward to increase the volume of the lungs. This downward movement displaces the abdominal organs, causing the stomach area to protrude.
Q14. Which one of the following pairs of nitrogenous bases of nucleic acids, is wrongly matched with the category mentioned against it ?
Correct Answer: (a)
Adenine and Guanine are Purines (double-ring). Thymine, Cytosine, and Uracil are Pyrimidines (single-ring).
Adenine and Guanine are Purines (double-ring). Thymine, Cytosine, and Uracil are Pyrimidines (single-ring).
Q15. If you wanted to study the use of ATP during a single contraction cycle within a muscle cell, which of the following processes would you use?
Correct Answer: (b)
A twitch is a single, brief contraction and relaxation cycle of a muscle fiber in response to a single action potential. This makes it the ideal unit for studying the molecular events and energy consumption of one contraction cycle.
A twitch is a single, brief contraction and relaxation cycle of a muscle fiber in response to a single action potential. This makes it the ideal unit for studying the molecular events and energy consumption of one contraction cycle.
Q16. Assertion: Curd is more nutritious than milk.
Reason: LAB increases the content of Vitamin B12 in curd.
Correct Answer: (a)
The addition of Vitamin B12 by LAB directly increases the nutritional value.
The addition of Vitamin B12 by LAB directly increases the nutritional value.
Q17. Gills are found in
Correct Answer: (d)
Gills are the primary respiratory organs for most aquatic organisms. They are found in all fish, many aquatic invertebrates (such as crustaceans and mollusks), and the larval stages (or some adult forms like the axolotl) of many amphibians.
Gills are the primary respiratory organs for most aquatic organisms. They are found in all fish, many aquatic invertebrates (such as crustaceans and mollusks), and the larval stages (or some adult forms like the axolotl) of many amphibians.
Q18. Which of the following statement is/are the correct about the events in aerobic respiration?
(i) The complete oxidation of pyruvate by the stepwise removal of all the hydrogen atoms, leaving three molecules of O2.
(ii) The complete oxidation of pyruvate by the stepwise removal of all the hydrogen atoms, leaving three molecules of CO2.
(iii) The passing on of the electrons removed as part of the hydrogen atoms to molecular O2 with simultaneous synthesis of ATP.
(iv) The passing on of the electrons removed as part of the hydrogen atoms to molecular O2 with simultaneous synthesis of ADP.
(i) The complete oxidation of pyruvate by the stepwise removal of all the hydrogen atoms, leaving three molecules of O2.
(ii) The complete oxidation of pyruvate by the stepwise removal of all the hydrogen atoms, leaving three molecules of CO2.
(iii) The passing on of the electrons removed as part of the hydrogen atoms to molecular O2 with simultaneous synthesis of ATP.
(iv) The passing on of the electrons removed as part of the hydrogen atoms to molecular O2 with simultaneous synthesis of ADP.
Correct Answer: (c)
Aerobic respiration involves the complete oxidation of pyruvate to three molecules of CO2 and the transfer of electrons to O2 to drive ATP synthesis.
Aerobic respiration involves the complete oxidation of pyruvate to three molecules of CO2 and the transfer of electrons to O2 to drive ATP synthesis.
Q19. The difference between exponential and logistic growth rates is that
Correct Answer: (d)
Logistic growth incorporates density-dependent factors through carrying capacity (K), which affect birth and death rates as population size increases. Exponential growth does not include such limits.
Logistic growth incorporates density-dependent factors through carrying capacity (K), which affect birth and death rates as population size increases. Exponential growth does not include such limits.
Q20. The overall goal of glycolysis, Kreb’s cycle and the electron transport system is the formation of:
Correct Answer: (d)
The stepwise breakdown of glucose allows the cell to capture energy efficiently in manageable units of ATP rather than releasing it all as heat in a single burst.
The stepwise breakdown of glucose allows the cell to capture energy efficiently in manageable units of ATP rather than releasing it all as heat in a single burst.
Q21. He places both plants under the same conditions and exposes each to a regimen of 10-hr days, expecting that the short-day plant will flower, and the long-day plant will not. You play a trick... Specifically, what did you have to do?
Correct Answer: (c)
Short-day plants require a long, uninterrupted dark period to flower. By providing a brief flash of light during the night (a 'night break'), you prevent the short-day plant from flowering and actually trigger flowering in a long-day plant.
Short-day plants require a long, uninterrupted dark period to flower. By providing a brief flash of light during the night (a 'night break'), you prevent the short-day plant from flowering and actually trigger flowering in a long-day plant.
Q22. Convergent evolution is often seen among species on different islands because
Correct Answer: (d)
When a species colonizes a new island with many vacant ecological niches, it undergoes adaptive radiation. If different lineages on different islands encounter similar niches (e.g., a specific type of forest floor), natural selection will often lead them to evolve similar morphological solutions independently.
When a species colonizes a new island with many vacant ecological niches, it undergoes adaptive radiation. If different lineages on different islands encounter similar niches (e.g., a specific type of forest floor), natural selection will often lead them to evolve similar morphological solutions independently.
Q23. Second messengers are activated in response to
Correct Answer: (c)
Hydrophilic (water-soluble) hormones cannot cross the phospholipid bilayer of the cell membrane. To exert their effects, they bind to cell-surface receptors, which then trigger the production of intracellular second messengers (like cAMP) to relay the signal.
Hydrophilic (water-soluble) hormones cannot cross the phospholipid bilayer of the cell membrane. To exert their effects, they bind to cell-surface receptors, which then trigger the production of intracellular second messengers (like cAMP) to relay the signal.
Q24. Ginger is an underground stem. It is distinguished from root because
Correct Answer: (c)
The presence of nodes and internodes is a definitive characteristic that identifies ginger as a stem.
The presence of nodes and internodes is a definitive characteristic that identifies ginger as a stem.
Q25. A forensic scientist cuts DNA from a crime scene and DNA from a suspect with the same enzyme. Which tool should the scientist use to separate the DNA fragments according to their size?
Correct Answer: (c)
Gel electrophoresis separates fragments of DNA according to their size. Bacterial transformation involves the uptake and expression of foreign DNA by bacteria, so choice (A) is incorrect. CRISPR-Cas9 is used for gene editing, so choice (B) is incorrect. PCR amplifies specific sequences of DNA, so choice (D) is also incorrect.
Gel electrophoresis separates fragments of DNA according to their size. Bacterial transformation involves the uptake and expression of foreign DNA by bacteria, so choice (A) is incorrect. CRISPR-Cas9 is used for gene editing, so choice (B) is incorrect. PCR amplifies specific sequences of DNA, so choice (D) is also incorrect.
Q26. Match the biocontrol agent with its target:
| Column I (Agent) | Column II (Target) |
|---|---|
| A. Ladybird | (I) Mosquitoes |
| B. Dragonflies | (II) Aphids |
| C. Bt-toxin | (III) Butterfly caterpillars |
Correct Answer: (a)
Standard biocontrol targets from section 8.5.
Standard biocontrol targets from section 8.5.
Q27. In comparing T-cell receptors and immunoglobulins
Correct Answer: (c)
T-cell receptors and immunoglobulins share similar structural features and both achieve diversity through gene rearrangement processes such as V(D)J recombination.
T-cell receptors and immunoglobulins share similar structural features and both achieve diversity through gene rearrangement processes such as V(D)J recombination.
Q28. Sex determination in birds follows the ZW system, where males have two copies of the Z chromosome (ZZ) and females are heterozygous (ZW). A male bird (who is heterozygous for a trait on the Z chromosome) is mated with a female bird (who expresses the recessive phenotype for that trait). Which of the following best describes their most likely offspring?
Correct Answer: (a)
(A) The following Punnett square shows the cross between a heterozygous male (ZAZa) and a female with the recessive trait (ZaW):
So 1/4 of the offspring would be males with the dominant phenotype, 1/4 would be males with the recessive phenotype, 1/4 would be females with the dominant phenotype, and 1/4 would be females with the recessive phenotype.
(A) The following Punnett square shows the cross between a heterozygous male (ZAZa) and a female with the recessive trait (ZaW):
| ZA | Za | Results | |
| Za | ZAZa | ZaZa | 1/4 males with dominant phenotype, 1/4 males with recessive phenotype |
| W | ZAW | ZaW | 1/4 females with dominant phenotype, 1/4 females with recessive phenotype |
So 1/4 of the offspring would be males with the dominant phenotype, 1/4 would be males with the recessive phenotype, 1/4 would be females with the dominant phenotype, and 1/4 would be females with the recessive phenotype.
Q29. Which of the following is responsible for the formation of the new cell wall and also represents the middle lamella between the walls of two adjacent cells?
Correct Answer: (a)
The cell plate formed during plant cytokinesis develops into the middle lamella, which provides the foundation for the primary cell walls of the daughter cells.
The cell plate formed during plant cytokinesis develops into the middle lamella, which provides the foundation for the primary cell walls of the daughter cells.
Q30. Splitting of water is associated with:
Correct Answer: (d)
The water-splitting complex is physically located on the inner side of the thylakoid membrane.
The water-splitting complex is physically located on the inner side of the thylakoid membrane.
Q31. White matter is ________, and gray matter is ________.
Correct Answer: (d)
White matter consists primarily of myelinated axons, giving it a white appearance. Gray matter consists of neuronal cell bodies, dendrites, and unmyelinated axons. Both are essential components of the central nervous system (CNS).
White matter consists primarily of myelinated axons, giving it a white appearance. Gray matter consists of neuronal cell bodies, dendrites, and unmyelinated axons. Both are essential components of the central nervous system (CNS).
Q32. Marine mammals are able to hold their breath for extended periods underwater because
Correct Answer: (c)
Marine mammals have high concentrations of myoglobin in their muscles. Myoglobin has a higher affinity for oxygen than hemoglobin, acting as an internal oxygen 'scuba tank' that allows them to remain submerged for long durations without access to atmospheric air.
Marine mammals have high concentrations of myoglobin in their muscles. Myoglobin has a higher affinity for oxygen than hemoglobin, acting as an internal oxygen 'scuba tank' that allows them to remain submerged for long durations without access to atmospheric air.
Q33. Which of the following best describes hormones?
Correct Answer: (b)
Hormones are chemical signaling molecules produced by endocrine glands. Unlike local paracrine signals, hormones are secreted into the bloodstream to reach distant target organs and generally remain active in the body for a longer duration to regulate physiological processes.
Hormones are chemical signaling molecules produced by endocrine glands. Unlike local paracrine signals, hormones are secreted into the bloodstream to reach distant target organs and generally remain active in the body for a longer duration to regulate physiological processes.
Q34. The ____ cannot be controlled by conscious thought.
Correct Answer: (c)
The autonomic nervous system regulates involuntary physiological processes such as heart rate, blood pressure, respiration, and digestion. In contrast, the somatic nervous system is associated with the voluntary control of body movements via skeletal muscles.
The autonomic nervous system regulates involuntary physiological processes such as heart rate, blood pressure, respiration, and digestion. In contrast, the somatic nervous system is associated with the voluntary control of body movements via skeletal muscles.
Q35. Match the phases of the menstrual cycle with events:
| Column-I (Phase) | Column-II (Event) |
|---|---|
| A. Menstrual phase | (I) Regeneration of endometrium |
| B. Follicular phase | (II) Formation of corpus luteum |
| C. Luteal phase | (III) Breakdown of endometrium |
Correct Answer: (a)
Based on Section 2.4 and Figure 2.9.
Based on Section 2.4 and Figure 2.9.
Q36. Worms use a hydrostatic skeleton to generate movement. How do they do this?
Correct Answer: (b)
A hydrostatic skeleton consists of a fluid-filled cavity (coelom) surrounded by muscles. When these muscles contract, they put pressure on the incompressible fluid, changing the animal's shape and allowing for movement like peristalsis.
A hydrostatic skeleton consists of a fluid-filled cavity (coelom) surrounded by muscles. When these muscles contract, they put pressure on the incompressible fluid, changing the animal's shape and allowing for movement like peristalsis.
Q37. Assertion: MTP is always a choice for birth control.
Reason: One is forced to use MTP to get rid of unwanted pregnancy due to casual coitus.
Correct Answer: (a)
MTP is not a regular birth control method; it is a last resort.
MTP is not a regular birth control method; it is a last resort.
Q38. The elimination of a predator by humans
Correct Answer: (c)
If a prey population was regulated by predation, removing the predator can allow prey numbers to increase, though other limiting factors may eventually constrain growth.
If a prey population was regulated by predation, removing the predator can allow prey numbers to increase, though other limiting factors may eventually constrain growth.
Q39. Identify the correct and incorrect statements from the following. (i) 17,500 new cells are produced per hour by a single maize root apical meristem. (ii) With the help of length, growth of pollen tube is measured. (iii) The growth of the leaf is measured in term of volume. (iv) Cells in a watermelon may increase in size by upto 3,500,000 times.
Correct Answer: (b)
Statement (iii) is wrong because leaf growth is typically measured in terms of surface area, not volume. The others are standard quantitative examples from NCERT.
Statement (iii) is wrong because leaf growth is typically measured in terms of surface area, not volume. The others are standard quantitative examples from NCERT.
Q40. Leaf abscission, fruit fall, bud dormancy occurs by which of the following phytohormone?
Correct Answer: (d)
Abscisic acid (ABA) acts as a general plant growth inhibitor, inducing seed and bud dormancy and promoting leaf abscission.
Abscisic acid (ABA) acts as a general plant growth inhibitor, inducing seed and bud dormancy and promoting leaf abscission.
Q41. Sex-linked recessive traits in humans are ________ likely to be expressed in ________.
Correct Answer: (c)
(C) Sex-linked genes are more likely to be expressed in males since males have only one X chromosome. Choice (A) is incorrect because sex-linked genes are more likely, not less likely, to be expressed in males. Females have two X chromosomes, so a sex-linked recessive trait is less likely to be expressed in females because a female would have to inherit two copies of the allele while a male would only have to inherit one copy of the allele for it to be expressed. Thus, choices (B) and (D) are both incorrect.
(C) Sex-linked genes are more likely to be expressed in males since males have only one X chromosome. Choice (A) is incorrect because sex-linked genes are more likely, not less likely, to be expressed in males. Females have two X chromosomes, so a sex-linked recessive trait is less likely to be expressed in females because a female would have to inherit two copies of the allele while a male would only have to inherit one copy of the allele for it to be expressed. Thus, choices (B) and (D) are both incorrect.
Q42. Which of the following is the example of acidic amino acid ?
Correct Answer: (d)
Glutamic acid and aspartic acid are both acidic amino acids because their R-groups contain an additional carboxyl group.
Glutamic acid and aspartic acid are both acidic amino acids because their R-groups contain an additional carboxyl group.
Q43. The amount of trace elements per kg dry matter is:
Correct Answer: (c)
Micronutrients or trace elements are needed in very small amounts (less than 10 mmole kg–1 of dry matter).
Micronutrients or trace elements are needed in very small amounts (less than 10 mmole kg–1 of dry matter).
Q44. Assertion: Sterilisation is a terminal method to prevent further pregnancies.
Reason: Reversibility of surgical methods is very poor.
Correct Answer: (a)
Poor reversibility makes it a 'terminal' choice.
Poor reversibility makes it a 'terminal' choice.
Q45. In comparing invertebrate and vertebrate excretory systems, you conclude that
Correct Answer: (d)
Vertebrate excretory systems involve filtration of blood followed by selective reabsorption of water and ions. Many invertebrate systems rely primarily on secretion rather than filtration, making option (d) correct.
Vertebrate excretory systems involve filtration of blood followed by selective reabsorption of water and ions. Many invertebrate systems rely primarily on secretion rather than filtration, making option (d) correct.
Q46. Assertion: Anaerobic sludge digesters produce biogas.
Reason: Bacteria produce methane, hydrogen sulphide, and CO2 in these tanks.
Correct Answer: (a)
The product of the digestion is the gas mixture known as biogas.
The product of the digestion is the gas mixture known as biogas.
Q47. Match the types of animals given in column I with their examples given in column II and choose the correct option.
| Column -I (Types of animals) | Column -II (Examples) |
|---|---|
| A. Limbless reptiles | I. Elephant |
| B. Jawless vertebrates | II. Lamprey |
| C. Flightless bird | III. Ichthyophis |
| D. Largest terrestrial animal | IV. Ostrich |
| E. Limbless amphibia | V. Cobra |
Correct Answer: (b)
A-V; B-II; C-IV; D-I; E-III.
A-V; B-II; C-IV; D-I; E-III.
Q48. The 'clot buster' enzyme used to remove clots from blood vessels of heart patients is:
Correct Answer: (c)
Page 5 states Streptokinase is used as a 'clot buster' for patients with myocardial infarction.
Page 5 states Streptokinase is used as a 'clot buster' for patients with myocardial infarction.
Q49. The organization which publishes the red list of species is
Correct Answer: (b)
The IUCN (International Union for Conservation of Nature) maintains and publishes the Red List of Threatened Species.
The IUCN (International Union for Conservation of Nature) maintains and publishes the Red List of Threatened Species.
Q50. In the genetic code, one codon
Correct Answer: (d)
The genetic code is based on triplets of nucleotides known as codons. Each codon consists of three bases and is highly specific, meaning that one particular codon specifies exactly one amino acid (though multiple different codons may specify the same amino acid, a property known as degeneracy).
The genetic code is based on triplets of nucleotides known as codons. Each codon consists of three bases and is highly specific, meaning that one particular codon specifies exactly one amino acid (though multiple different codons may specify the same amino acid, a property known as degeneracy).
Q51. Regarding the placenta:
(i) It supplies oxygen and nutrients to the embryo.
(ii) It removes carbon dioxide and waste.
(iii) It secretes hCG, hPL, and estrogens.
(i) It supplies oxygen and nutrients to the embryo.
(ii) It removes carbon dioxide and waste.
(iii) It secretes hCG, hPL, and estrogens.
Correct Answer: (a)
Placenta is vital for both metabolic exchange and endocrine support.
Placenta is vital for both metabolic exchange and endocrine support.
Q52. Lactational amenorrhea is effective as a contraceptive for a maximum period of ______ months following parturition.
Correct Answer: (b)
Lactational amenorrhea... has been reported to be effective only upto a maximum period of six months following parturition.
Lactational amenorrhea... has been reported to be effective only upto a maximum period of six months following parturition.
Q53. An important essential element which is required by plants in the greatest amount is:
Correct Answer: (a)
Nitrogen is the essential nutrient element required by plants in the largest amount.
Nitrogen is the essential nutrient element required by plants in the largest amount.
Q54. Cells that do not have power of cell division are produced by
Correct Answer: (d)
Meristems like primary meristem and cambium produce cells that eventually differentiate into permanent tissues, which lose the ability to divide.
Meristems like primary meristem and cambium produce cells that eventually differentiate into permanent tissues, which lose the ability to divide.
Q55. Hormones released from the pituitary gland have two different sources. Those that are produced by the neurons of the hypothalamus are released through the _____________, and those produced within the pituitary are released through the _____________.
Correct Answer: (b)
The posterior pituitary (neurohypophysis) stores and releases hormones produced by hypothalamic neurons (such as ADH and oxytocin). The anterior pituitary (adenohypophysis) synthesizes and secretes its own hormones (such as GH and ACTH).
The posterior pituitary (neurohypophysis) stores and releases hormones produced by hypothalamic neurons (such as ADH and oxytocin). The anterior pituitary (adenohypophysis) synthesizes and secretes its own hormones (such as GH and ACTH).
Q56. Which of the following is an incorrect match of essential element and function?
Correct Answer: (a)
Magnesium (Mg), not manganese, is the central structural atom of the chlorophyll molecule.
Magnesium (Mg), not manganese, is the central structural atom of the chlorophyll molecule.
Q57. Match the followings and choose the correct option from below.
| A. Meristem | (i) photosynthesis, storage |
| B. Parenchyma | (ii) mechanical support |
| C. Collenchyma | (iii) actively dividing cells |
| D. Sclerenchyma | (iv) stomata |
| E. Epidermal tissue | (v) sclereids |
Correct Answer: (b)
Meristem divides; Parenchyma is metabolic; Collenchyma provides support; Sclerenchyma contains sclereids; Epidermis contains stomata.
Meristem divides; Parenchyma is metabolic; Collenchyma provides support; Sclerenchyma contains sclereids; Epidermis contains stomata.
Q58. Match the following and select the correct answer:
| Column I | Column II |
|---|---|
| A. Centriole | I. Infoldings in mitochondria |
| B. Chlorophyll | II. Thylakoids |
| C. Cristae | III. Nucleic acids |
| D. Ribozymes | IV. Basal body cilia or flagella |
Correct Answer: (a)
Centriole forms basal bodies; Chlorophyll is in thylakoids; Cristae are mitochondrial folds; Ribozymes are catalytic RNA (nucleic acids).
Centriole forms basal bodies; Chlorophyll is in thylakoids; Cristae are mitochondrial folds; Ribozymes are catalytic RNA (nucleic acids).
Q59. Five kingdom system of classification suggested by R.H. Whittaker is not based on
Correct Answer: (a)
While cell type is a factor, the fundamental distinction between prokaryotes and eukaryotes (nucleus presence) was already used; the unique focus of his system was the criteria of nutrition, body organization, and reproduction.
While cell type is a factor, the fundamental distinction between prokaryotes and eukaryotes (nucleus presence) was already used; the unique focus of his system was the criteria of nutrition, body organization, and reproduction.
Q60. Assertion: Periodic abstinence is a natural method of birth control.
Reason: Couples avoid coitus from day 10 to 17 of the menstrual cycle.
Correct Answer: (a)
The method is defined by avoiding the most fertile window.
The method is defined by avoiding the most fertile window.
Q61. Stem tendrils are found in
Correct Answer: (d)
Stem tendrils, which develop from axillary buds, are slender and spirally coiled and help plants to climb as in gourds (cucumber, pumpkins, watermelon) and grapevines.
Stem tendrils, which develop from axillary buds, are slender and spirally coiled and help plants to climb as in gourds (cucumber, pumpkins, watermelon) and grapevines.
Q62. Asexual reproduction is likely to be most common in which ecosystem?
Correct Answer: (a)
Asexual reproduction is favored in stable and predictable environments. Tropical rainforests provide such conditions because they have a constant temperature, high and regular rainfall, and very little seasonal variation. This environmental stability allows organisms to survive and reproduce successfully without the need for genetic variation. In contrast, temperate grasslands experience strong seasonal changes, the arctic tundra has extremely cold and harsh conditions, and deciduous forests show marked seasonal variation, all of which favor sexual reproduction rather than asexual reproduction.
Asexual reproduction is favored in stable and predictable environments. Tropical rainforests provide such conditions because they have a constant temperature, high and regular rainfall, and very little seasonal variation. This environmental stability allows organisms to survive and reproduce successfully without the need for genetic variation. In contrast, temperate grasslands experience strong seasonal changes, the arctic tundra has extremely cold and harsh conditions, and deciduous forests show marked seasonal variation, all of which favor sexual reproduction rather than asexual reproduction.
Q63. Match the terms given in column I with their features given in column II and choose the correct option.
| Column-I (Terms) | Column-II (Features) |
|---|---|
| A. Fibres | I. Cells are living and thin walled with cellulosic cell wall, store food materials in the form of starch or fat |
| B. Sclereids | II. Main water conductive cells of the pteridophytes and the gymnosperms |
| C. Tracheids | III. Thick walled, elongated and pointed cells, generally occurring in groups |
| D. Vessels | IV. Long cylindrical tube like structure and cells are devoid of protoplasm. Characteristic feature of angiosperms |
| E. Xylem parenchyma | V. Reduced form of sclerenchyma cells with highly thickened lignified cellular walls that form small bundles of durable layers of tissue in most plants. |
Correct Answer: (b)
Fibres are pointed and grouped; Sclereids are highly thickened; Tracheids conduct in gymnosperms; Vessels are characteristic of angiosperms; Parenchyma is living and stores food.
Fibres are pointed and grouped; Sclereids are highly thickened; Tracheids conduct in gymnosperms; Vessels are characteristic of angiosperms; Parenchyma is living and stores food.
Q64. The given figure shows apical meristem of root apex with few part marked as A, B and C. Identify the correct labelling of A, B and C.
Correct Answer: (c)
In the root apex, A corresponds to the cortex, B is the protoderm (outer layer), and C is the protective root cap.
In the root apex, A corresponds to the cortex, B is the protoderm (outer layer), and C is the protective root cap.
Q65. An osmoregulator would maintain its internal fluids at a concentration that is ____ relative to its surroundings.
Correct Answer: (d)
Osmoregulators actively control their internal osmotic concentration and may maintain body fluids that are hypertonic, hypotonic, or isotonic relative to the external environment, depending on ecological conditions.
Osmoregulators actively control their internal osmotic concentration and may maintain body fluids that are hypertonic, hypotonic, or isotonic relative to the external environment, depending on ecological conditions.
Q66. Megaspores are produced in
Correct Answer: (d)
In the life cycle of an angiosperm, the megaspore mother cell located within the ovule undergoes meiosis to produce four haploid megaspores (though usually only one survives).
In the life cycle of an angiosperm, the megaspore mother cell located within the ovule undergoes meiosis to produce four haploid megaspores (though usually only one survives).
Q67. A shark’s blood is isotonic to the surrounding seawater because of the reabsorption of ____ in its blood.
Correct Answer: (c)
Sharks retain high concentrations of urea in their blood. This raises the osmolarity of their body fluids, making them isotonic with seawater and preventing excessive water loss by osmosis.
Sharks retain high concentrations of urea in their blood. This raises the osmolarity of their body fluids, making them isotonic with seawater and preventing excessive water loss by osmosis.
Q68. G protein–coupled receptors are involved in the nervous system by
Correct Answer: (d)
G protein–coupled receptors (metabotropic receptors) act as postsynaptic receptors that, upon binding neurotransmitters, initiate complex intracellular signaling cascades. These are distinct from ionotropic receptors, which are ligand-gated ion channels themselves.
G protein–coupled receptors (metabotropic receptors) act as postsynaptic receptors that, upon binding neurotransmitters, initiate complex intracellular signaling cascades. These are distinct from ionotropic receptors, which are ligand-gated ion channels themselves.
Q69. Which one is correct about crossing over/genetic recombination?
(i) It occurs in tetrad stage which occurs in pachytene of prophase I of meiosis I.
(ii) It occurs between non-sister chromatids of homologous chromosomes.
(iii) It is recombinase enzyme mediated process.
(iv) It is also the reciprocal transfer of genes between the non-homologous chromosomes
(i) It occurs in tetrad stage which occurs in pachytene of prophase I of meiosis I.
(ii) It occurs between non-sister chromatids of homologous chromosomes.
(iii) It is recombinase enzyme mediated process.
(iv) It is also the reciprocal transfer of genes between the non-homologous chromosomes
Correct Answer: (b)
Crossing over happens between homologous chromosomes, not non-homologous ones. Statements (i), (ii), and (iii) are correct.
Crossing over happens between homologous chromosomes, not non-homologous ones. Statements (i), (ii), and (iii) are correct.
Q70. Rh positive (R) is a trait that is dominant over Rh negative (r). A woman, who is Rh positive, has a son, who is Rh negative.
Which of the following is a true statement about the mother?
Which of the following is a true statement about the mother?
Correct Answer: (c)
Since the mother is Rh positive, she must have at least one dominant R allele. Since she has a child who is Rh negative, she must have an r allele. Therefore, the mother must be heterozygous Rr. Choice (A) is incorrect because if the mother was rr, she would not be Rh positive. Choice (B) is incorrect because an RR mother could not produce an Rh negative child. Choice (D) is incorrect because since the mother is Rh positive and her son is Rh negative, they cannot have the same genotype.
Since the mother is Rh positive, she must have at least one dominant R allele. Since she has a child who is Rh negative, she must have an r allele. Therefore, the mother must be heterozygous Rr. Choice (A) is incorrect because if the mother was rr, she would not be Rh positive. Choice (B) is incorrect because an RR mother could not produce an Rh negative child. Choice (D) is incorrect because since the mother is Rh positive and her son is Rh negative, they cannot have the same genotype.
Q71. Match the androecium formula (given in column II) with their family (given in column I) and choose the correct combination from the options given below.
| Column-I (Family) | Column-II (Androecium formula) |
|---|---|
| A. Brassicaceae | I. A3 + 3 |
| B. Fabaceae | II. A(5) |
| C. Solanaceae | III. A(9) + 1 |
| D. Liliaceae | IV. A2 + 4 |
Correct Answer: (a)
Brassicaceae is tetradynamous (2+4). Fabaceae is diadelphous ((9)+1). Solanaceae has 5 stamens. Liliaceae has 6 stamens in two whorls (3+3).
Brassicaceae is tetradynamous (2+4). Fabaceae is diadelphous ((9)+1). Solanaceae has 5 stamens. Liliaceae has 6 stamens in two whorls (3+3).
Q72. As population size (N) approaches the carrying capacity (K) in the logistic growth model, dN/dt =
Correct Answer: (b)
When N approaches K, resources become limiting and population growth slows. At carrying capacity, births and deaths balance, so the growth rate (dN/dt) approaches zero.
When N approaches K, resources become limiting and population growth slows. At carrying capacity, births and deaths balance, so the growth rate (dN/dt) approaches zero.
Q73. Identify the figure with its correct name and phylum.
Correct Answer: (c)
Figure shows Balanoglossus (Acorn worm).
Figure shows Balanoglossus (Acorn worm).
Q74. Which of the following is the most important cause for animals and plants being driven to extinction?
Correct Answer: (a)
Habitat loss is the primary cause of the current biodiversity crisis.
Habitat loss is the primary cause of the current biodiversity crisis.
Q75. Which of the following plant parts elongates directly and leads to the formation of primary roots?
Correct Answer: (b)
The radicle of the embryo elongates directly to form the primary root in dicotyledonous plants.
The radicle of the embryo elongates directly to form the primary root in dicotyledonous plants.
Q76. Select one which is not true for ribosomes.
Correct Answer: (d)
Ribosomes are specifically known as the protein factories of the cell.
Ribosomes are specifically known as the protein factories of the cell.
Q77. You experience a longer period than normal between meals. Your body’s response to this will be to produce
Correct Answer: (b)
During periods of fasting (between meals), blood glucose levels drop. The pancreas responds by secreting glucagon, which stimulates the liver to break down glycogen into glucose and release it into the blood, thereby raising blood sugar levels back to homeostatic levels.
During periods of fasting (between meals), blood glucose levels drop. The pancreas responds by secreting glucagon, which stimulates the liver to break down glycogen into glucose and release it into the blood, thereby raising blood sugar levels back to homeostatic levels.
Q78. In terms of studying gene function, what is the main benefit that genome editing has over RNAi?
Correct Answer: (a)
RNA interference (RNAi) is a 'knockdown' technology that degrades mRNA or blocks translation, resulting in reduced protein levels but often leaving some function intact. Genome editing (like CRISPR/Cas9) creates permanent changes in the DNA sequence, allowing for a complete 'knockout' or total elimination of the gene's function.
RNA interference (RNAi) is a 'knockdown' technology that degrades mRNA or blocks translation, resulting in reduced protein levels but often leaving some function intact. Genome editing (like CRISPR/Cas9) creates permanent changes in the DNA sequence, allowing for a complete 'knockout' or total elimination of the gene's function.
Q79. Which of the following statements best describes the sliding filament mechanism of muscle contraction?
Correct Answer: (a)
During muscle contraction, the individual protein filaments (actin and myosin) maintain their original length. The sarcomere shortens because the thin actin filaments are pulled over the thick myosin filaments, increasing the degree of overlap.
During muscle contraction, the individual protein filaments (actin and myosin) maintain their original length. The sarcomere shortens because the thin actin filaments are pulled over the thick myosin filaments, increasing the degree of overlap.
Q80. Many factors can limit the ability of natural selection to cause evolutionary change, including
Correct Answer: (d)
Natural selection is not an all-powerful force. It is constrained by the raw material available (genetic variation). Furthermore, evolutionary trade-offs exist, such as a trait that increases mating success but decreases lifespan. Pleiotropy also acts as a constraint because a beneficial change in one trait might be linked to a harmful change in another trait controlled by the same gene.
Natural selection is not an all-powerful force. It is constrained by the raw material available (genetic variation). Furthermore, evolutionary trade-offs exist, such as a trait that increases mating success but decreases lifespan. Pleiotropy also acts as a constraint because a beneficial change in one trait might be linked to a harmful change in another trait controlled by the same gene.
Q81. The primary difference between sedimentary and atmospheric cycles is that in _____ cycles the nutrient does not _____
Correct Answer: (d)
In sedimentary cycles, there is no significant gaseous phase, so the nutrient does not enter the atmosphere.
In sedimentary cycles, there is no significant gaseous phase, so the nutrient does not enter the atmosphere.
Q82. A major characteristic of the monocot root is the presence of
Correct Answer: (b)
Monocot roots are characterized by a lack of vascular cambium, meaning they do not undergo secondary thickening.
Monocot roots are characterized by a lack of vascular cambium, meaning they do not undergo secondary thickening.
Q83. The given figures (A, B, C, D) represent different algae. Identify the correct option for the given diagrams.
| S. No. | A | B | C | D |
|---|---|---|---|---|
| (a) | Porphyra | Fucus | Dictyota | Polysiphonia |
| (b) | Polysiphonia | Porphyra | Dictyota | Fucus |
| (c) | Fucus | Dictyota | Porphyra | Polysiphonia |
| (d) | Porphyra | Polysiphonia | Fucus | Dictyota |
Correct Answer: (a)
Based on morphological features in standard texts: A is Porphyra (Red), B is Fucus (Brown), C is Dictyota (Brown), and D is Polysiphonia (Red).
Based on morphological features in standard texts: A is Porphyra (Red), B is Fucus (Brown), C is Dictyota (Brown), and D is Polysiphonia (Red).
Q84. Flame cells present in platyhelminthes are specialized in
Correct Answer: (d)
Flame cells are excretory structures involved in osmoregulation and excretion.
Flame cells are excretory structures involved in osmoregulation and excretion.
Q85. Natural selection can lead to speciation
Correct Answer: (b)
Speciation is often an incidental byproduct of adaptive divergence. As two populations adapt to different environmental conditions or niches, they accumulate different genetic changes. These changes may eventually result in reproductive barriers, such as different mating times or incompatible gametes.
Speciation is often an incidental byproduct of adaptive divergence. As two populations adapt to different environmental conditions or niches, they accumulate different genetic changes. These changes may eventually result in reproductive barriers, such as different mating times or incompatible gametes.
Q86. Paramecium
(i) is a ciliated protozoan.
(ii) has a cavity that opens to the outside the cell surface.
(iii) shows water current maintained by cilia which helps the food to be steared into gullet.
Which of the statement given above are correct?
(i) is a ciliated protozoan.
(ii) has a cavity that opens to the outside the cell surface.
(iii) shows water current maintained by cilia which helps the food to be steared into gullet.
Which of the statement given above are correct?
Correct Answer: (d)
Paramecium uses its cilia for locomotion and to direct food into its cytostome (gullet) via the oral groove.
Paramecium uses its cilia for locomotion and to direct food into its cytostome (gullet) via the oral groove.
Q87. A scientist at a pharmaceutical company wants to create bacteria that will synthesize human growth hormone.
The scientist has successfully created a plasmid that contains the DNA code for the human growth hormone gene. Which technique should the scientist use to insert the plasmid into a cell?
The scientist has successfully created a plasmid that contains the DNA code for the human growth hormone gene. Which technique should the scientist use to insert the plasmid into a cell?
Correct Answer: (a)
Bacterial transformation inserts naked, foreign DNA into a bacterial cell. CRISPR-Cas9 is used for gene editing, not inserting plasmids into a cell, so choice (B) is incorrect. Choice (C) is incorrect because gel electrophoresis is used to separate DNA fragments according to their size. Polymerase chain reaction is used to amplify the number of copies of a specific DNA sequence, so choice (D) is incorrect.
Bacterial transformation inserts naked, foreign DNA into a bacterial cell. CRISPR-Cas9 is used for gene editing, not inserting plasmids into a cell, so choice (B) is incorrect. Choice (C) is incorrect because gel electrophoresis is used to separate DNA fragments according to their size. Polymerase chain reaction is used to amplify the number of copies of a specific DNA sequence, so choice (D) is incorrect.
Q88. Which of the following statement(s) is/are correct about pteridophytes?
(i) The main plant body is a sporophyte which is differentiated into true roots and leaves.
(ii) The leaves are small (microphylls) as in ferns or large (macrophylls) as in Selaginella.
(iii) Genera like Selaginella and Salvinia which produce two kinds of spores–macro (large) and micro (small) spores, are known as heterospores.
(iv) Common examples are Funaria, Polytrichum and Sphagnum.
(i) The main plant body is a sporophyte which is differentiated into true roots and leaves.
(ii) The leaves are small (microphylls) as in ferns or large (macrophylls) as in Selaginella.
(iii) Genera like Selaginella and Salvinia which produce two kinds of spores–macro (large) and micro (small) spores, are known as heterospores.
(iv) Common examples are Funaria, Polytrichum and Sphagnum.
Correct Answer: (c)
Statement (ii) is swapped (ferns have megaphylls, Selaginella has microphylls). Statement (iv) lists mosses, which are bryophytes.
Statement (ii) is swapped (ferns have megaphylls, Selaginella has microphylls). Statement (iv) lists mosses, which are bryophytes.
Q89. If you hold your breath for a long time, body CO2 levels are likely to ________, and the pH of body fluids is likely to ________.
Correct Answer: (c)
When breathing is suspended, carbon dioxide (CO2) accumulates in the blood. CO2 reacts with water to form carbonic acid, which dissociates into hydrogen ions (H+) and bicarbonate. An increase in H+ concentration directly causes the pH to decrease (become more acidic).
When breathing is suspended, carbon dioxide (CO2) accumulates in the blood. CO2 reacts with water to form carbonic acid, which dissociates into hydrogen ions (H+) and bicarbonate. An increase in H+ concentration directly causes the pH to decrease (become more acidic).
Q90. Organisms of which of the following kingdom do not have nuclear membrane ?
Correct Answer: (c)
Kingdom Monera consists of prokaryotes, which lack a well-defined nucleus and nuclear membrane.
Kingdom Monera consists of prokaryotes, which lack a well-defined nucleus and nuclear membrane.