Q1. In a hypothetical plant, gene 'A' for flower color exhibits incomplete dominance (AA-Red, Aa-Pink, aa-White) and gene 'B' for plant height is completely dominant (BB/Bb-Tall, bb-Dwarf). If a plant with genotype AABb is crossed with a plant of genotype Aabb, what will be the phenotypic ratio of the offspring?
Correct Answer: Option A (3:1:3:1)
Explanation: Detailed explanation will be updated shortly.
Q2. A patient presents with symptoms of polyuria (excessive urination) and polydipsia (excessive thirst), but their blood glucose levels are normal. A deficiency in which of the following is the most probable cause?
Correct Answer: Option A (Secretion of insulin from β-cells of the pancreas.)
Explanation: Detailed explanation will be updated shortly.
Q3. A student is designing a PCR experiment but mistakenly uses a DNA polymerase isolated from *E. coli* instead of *Taq* polymerase. All other conditions (primers, dNTPs, template DNA) are optimal. What would be the most likely outcome after the first cycle?
Correct Answer: Option A (are optimal. What would be the most likely outcome after the first cycle?)
Explanation: Detailed explanation will be updated shortly.
Q4. In the context of the lac operon, a mutation occurs in the operator site (O) that prevents the repressor protein from binding. How will this affect the transcription of the structural genes (z, y, a) in the absence of lactose?
Correct Answer: Option A (The genes will not be transcribed.)
Explanation: Detailed explanation will be updated shortly.
Q5. Consider a food chain in a deep ocean benthic environment: Phytoplankton -> Zooplankton -> Small Fish -> Large Fish. If you were to construct a pyramid of biomass for this ecosystem, what would be its most likely shape?
Correct Answer: Option A (Upright)
Explanation: Detailed explanation will be updated shortly.
Q6. A farmer wishes to prevent lodging (bending of stems) in his cereal crop and simultaneously promote the rooting of cuttings for propagation. Which combination of phytohormones would be most effective for these two separate applications respectively?
Correct Answer: Option A (Gibberellin for preventing lodging; Auxin for rooting.)
Explanation: Detailed explanation will be updated shortly.
Q7. During a study of a population, it was observed that the introduction of a new predator led to the preferential hunting of individuals with intermediate body size. Over several generations, the population diverged into two groups: one with smaller body sizes and one with larger body sizes. This is a classic example of:
Correct Answer: Option A (Stabilising Selection)
Explanation: Detailed explanation will be updated shortly.
Q8. A recombinant pBR322 plasmid contains a gene of interest inserted at the PstI site. This plasmid is used to transform *E. coli* cells. To specifically select for the transformed cells containing the *recombinant* plasmid, the cells should be plated on a medium containing:
Correct Answer: Option A (Only tetracycline.)
Explanation: Detailed explanation will be updated shortly.
Q9. If the Atrioventricular (AV) node in the human heart becomes non-functional, what would be the immediate effect on the cardiac cycle?
Correct Answer: Option A (The rate of ventricular contraction will increase significantly.)
Explanation: Detailed explanation will be updated shortly.
Q10. A defining evolutionary trend in the plant kingdom is the gradual reduction of the gametophytic generation. Which of the following groups shows a dominant, photosynthetic gametophyte that is nutritionally independent of the sporophyte?
Correct Answer: Option A (Angiosperms)
Explanation: Detailed explanation will be updated shortly.
Q11. A mutation replaces a Leucine (a non-polar amino acid) with an Aspartic acid (a charged, acidic amino acid) in the core of a globular protein that functions in a non-polar lipid membrane. What is the most likely consequence?
Correct Answer: Option A (The primary structure of the protein will change, but its function will be unaffected.)
Explanation: Detailed explanation will be updated shortly.
Q12. Guttation is a process distinct from transpiration. The primary driving force for guttation is ________ and it occurs when the rate of ________ is low.
Correct Answer: Option A (Root pressure; absorption)
Explanation: Detailed explanation will be updated shortly.
Q13. In a population at Hardy-Weinberg equilibrium, the frequency of the allele for albinism (an autosomal recessive trait) is 0.1. What is the expected frequency of heterozygous individuals (carriers) in this population?
Correct Answer: Option A (0.01)
Explanation: Detailed explanation will be updated shortly.
Q14. A biologist discovers a new organism. It has a cell wall made of chitin, a heterotrophic mode of nutrition, and reproduces via spores. It forms a symbiotic association with the roots of a pine tree, enhancing the tree's nutrient uptake. The organism is a _______ and the interaction is _______.
Correct Answer: Option A (Bacterium; Parasitism)
Explanation: Detailed explanation will be updated shortly.
Q15. A woman is using a combined oral contraceptive pill that contains a synthetic estrogen and progesterone. Which of the following correctly describes the primary physiological effect?
Correct Answer: Option A (It causes the degeneration of the corpus luteum immediately after ovulation.)
Explanation: Detailed explanation will be updated shortly.
Q16. Apomixis is a unique reproductive strategy in some plants because it:
Correct Answer: Option A (Produces fruits without fertilization, resulting in seedless varieties.)
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 (The role of a keystone species in an ecosystem.)
Explanation: Detailed explanation will be updated shortly.
Q18. If the mechanism for urea recycling in the kidney's medulla was impaired, what would be the most direct consequence?
Correct Answer: Option A (An increase in the glomerular filtration rate (GFR).)
Explanation: Detailed explanation will be updated shortly.
Q19. A pedigree chart for a genetic disorder shows that affected parents can have an unaffected child, and the trait appears in both males and females. What is the most likely mode of inheritance?
Correct Answer: Option A (Autosomal recessive)
Explanation: Detailed explanation will be updated shortly.
Q20. In the process of gel electrophoresis, DNA fragments are separated based on their size. What is the role of Ethidium Bromide (EtBr) in this technique?
Correct Answer: Option A (It provides a negative charge to the DNA fragments.)
Explanation: Detailed explanation will be updated shortly.