Q1. A geneticist observes that in a dihybrid cross involving genes 'P' and 'Q', the F2 generation shows a phenotypic ratio of 1:2:1:2:4:2:1:2:1 instead of the expected 9:3:3:1. This observation strongly suggests that:
Correct Answer: Option A (Both genes are exhibiting incomplete dominance.)
Explanation: Detailed explanation will be updated shortly.
Q2. A patient presents with symptoms of severe dehydration. A urine analysis reveals a very high volume of dilute urine, but a blood test shows normal blood glucose levels. Which part of the nephron is most likely malfunctioning?
Correct Answer: Option A (The glomerulus, leading to excessive filtration.)
Explanation: Detailed explanation will be updated shortly.
Q3. In an aquatic ecosystem, a non-biodegradable pesticide is introduced. Which of the following graphical representations most accurately depicts the concentration of the pesticide (Y-axis) across different trophic levels (X-axis)?
Correct Answer: Option A (A downward sloping curve from producers to top consumers.)
Explanation: Detailed explanation will be updated shortly.
Q4. A scientist is attempting to create a transgenic plant resistant to a specific herbicide. The herbicide works by blocking an essential enzyme in the chloroplast. The most effective genetic modification strategy would be to introduce a gene that:
Correct Answer: Option A (Encodes a protein that degrades the herbicide inside the cytoplasm.)
Explanation: Detailed explanation will be updated shortly.
Q5. Consider the lac operon in E. coli. If a mutation occurs in the operator site (O) such that the repressor protein can no longer bind to it, what would be the outcome for the expression of the structural genes (z, y, a)?
Correct Answer: Option A (The genes will never be expressed, even in the presence of lactose.)
Explanation: Detailed explanation will be updated shortly.
Q6. During the processing of a primary transcript (hnRNA) in a eukaryotic cell, a hypothetical drug 'Splice-Block' is introduced which inhibits the function of snRNPs (small nuclear ribonucleoproteins). The most immediate consequence would be:
Correct Answer: Option A (in a eukaryotic cell, a hypothetical drug 'Splice-Block' is introduced which inhibits the function of snRNPs (small nuclear ribonucleoproteins). The most immediate consequence would be:)
Explanation: Detailed explanation will be updated shortly.
Q7. In a population at Hardy-Weinberg equilibrium, the frequency of the allele for albinism (a recessive trait) is 0.1. If a catastrophic event randomly eliminates 50% of the homozygous dominant individuals, what will be the new frequency of the heterozygous individuals in the surviving population?
Correct Answer: Option A (0.18)
Explanation: Detailed explanation will be updated shortly.
Q8. A person living at sea level moves to a high-altitude location like Leh. Which of the following physiological changes would be the *last* to occur as part of acclimatization?
Correct Answer: Option A (Increased breathing rate.)
Explanation: Detailed explanation will be updated shortly.
Q9. In plant tissue culture, a high auxin to cytokinin ratio in the nutrient medium generally promotes:
Correct Answer: Option A (Proliferation of undifferentiated callus.)
Explanation: Detailed explanation will be updated shortly.
Q10. Which of the following immune responses is incorrectly paired with its example?
Correct Answer: Option A (Artificially Acquired Active Immunity - Vaccination with attenuated pathogens.)
Explanation: Detailed explanation will be updated shortly.
Q11. A pollen grain with 10 chromosomes fertilizes an egg cell with 10 chromosomes. The resulting zygote develops into an embryo, but the endosperm nucleus is found to have 27 chromosomes. This suggests that:
Correct Answer: Option A (The egg cell was diploid.)
Explanation: Detailed explanation will be updated shortly.
Q12. In the context of ecological succession on a bare rock, which organism's activity is most crucial for creating a soil layer that allows for the establishment of larger plants?
Correct Answer: Option A (Mosses, by trapping wind-blown dust.)
Explanation: Detailed explanation will be updated shortly.
Q13. The technique of DNA fingerprinting, as developed by Alec Jeffreys, relies on the detection of:
Correct Answer: Option A (Single Nucleotide Polymorphisms (SNPs) using PCR.)
Explanation: Detailed explanation will be updated shortly.
Q14. A patient's ECG shows a significantly prolonged Q-T interval. This indicates a potential problem with:
Correct Answer: Option A (The time taken for atrial depolarization.)
Explanation: Detailed explanation will be updated shortly.
Q15. If the water potential (Ψw) of a root hair cell is -0.5 MPa and the water potential of the surrounding soil water is -0.2 MPa, what will be the net direction of water movement?
Correct Answer: Option A (From the soil into the root hair.)
Explanation: Detailed explanation will be updated shortly.
Q16. A key difference between the lytic and lysogenic cycles of a bacteriophage is that in the lysogenic cycle:
Correct Answer: Option A (The host cell is immediately destroyed.)
Explanation: Detailed explanation will be updated shortly.
Q17. The 'Rivet Popper Hypothesis' proposed by Paul Ehrlich is an analogy used to explain the importance of:
Correct Answer: Option A (A keystone species in an ecosystem.)
Explanation: Detailed explanation will be updated shortly.
Q18. In oogenesis, the first meiotic division is completed:
Correct Answer: Option A (During fetal development.)
Explanation: Detailed explanation will be updated shortly.
Q19. A C4 plant and a C3 plant are grown together in a sealed chamber with a limited supply of CO2 and high light intensity. Which of the following is most likely to occur?
Correct Answer: Option A (The C3 plant will outcompete the C4 plant due to lower ATP requirements.)
Explanation: Detailed explanation will be updated shortly.
Q20. A patient is diagnosed with an autoimmune disorder where their own immune cells are attacking the myelin sheath of neurons in the central nervous system. This condition is known as:
Correct Answer: Option A (Myasthenia Gravis)
Explanation: Detailed explanation will be updated shortly.
Q21. In a population, 64% of individuals express the dominant phenotype. Assuming the population is in Hardy-Weinberg equilibrium, what percentage of the population is heterozygous for this trait?
Correct Answer: Option A (32%)
Explanation: Detailed explanation will be updated shortly.
Q22. A pollen grain with 10 chromosomes fertilizes an egg cell with 10 chromosomes. The resulting zygote is diploid, but the primary endosperm nucleus is found to have 30 chromosomes. This indicates that:
Correct Answer: Option A (The egg cell was diploid.)
Explanation: Detailed explanation will be updated shortly.