Question 1

Q1. In DNA replication, which enzyme synthesizes short RNA primers?

Accepted Answer

Option B: Primase. Primase synthesizes short RNA primers required for DNA polymerase to initiate replication.

Question 2

Q2. In human evolution, increased brain size is mainly associated with:

Accepted Answer

Option D: Homo sapiens sapiens. Modern humans show maximum cranial capacity and advanced cognitive abilities.

Question 3

Q3. Which of the following is NOT a part of innate immunity?

Accepted Answer

Option C: Memory cells. Memory cells belong to adaptive immunity, not innate immunity.

Question 4

Q4. The correct sequence of nitrogen bases pairing in DNA is:

Accepted Answer

Option C: A–T, G–C. DNA follows complementary base pairing: Adenine with Thymine, Guanine with Cytosine.

Question 5

Q5. Which structure is responsible for transfer of genetic material during bacterial conjugation?

Accepted Answer

Option A: Pili. Sex pili connect bacteria and transfer plasmid DNA during conjugation.

Question 6

Q6. A test cross is performed to determine:

Accepted Answer

Option B: Genotype of dominant phenotype. Test cross reveals whether dominant phenotype is homozygous or heterozygous.

Question 7

Q7. Which phase of meiosis is responsible for reduction of chromosome number?

Accepted Answer

Option B: Anaphase I. Homologous chromosomes separate during Anaphase I, reducing chromosome number.

Question 8

Q8. Which of the following best describes ecological succession?

Accepted Answer

Option B: Gradual change in ecosystem structure over time. Succession is the gradual and orderly replacement of communities.

Question 9

Q9. In biotechnology, plasmids are used because they:

Accepted Answer

Option B: Carry genes of interest. Plasmids serve as vectors for gene transfer.

Question 10

Q10. Which molecule carries amino acids to ribosomes during protein synthesis?

Accepted Answer

Option C: tRNA. tRNA brings specific amino acids to ribosomes during translation.

Question 11

Q11. Which contraceptive method prevents implantation?

Accepted Answer

Option B: Copper-T. Copper-T prevents fertilized egg implantation in uterus.

Question 12

Q12. A person suffering from AIDS is affected due to deficiency of:

Accepted Answer

Option C: Helper T-cells. HIV targets CD4+ helper T cells, weakening immune system.

Question 13

Q13. Biomagnification is maximum in:

Accepted Answer

Option D: Tertiary consumers. Toxic substances increase at higher trophic levels.

Question 14

Q14. Assertion (A): DNA replication is semiconservative. Reason (R): Each daughter DNA contains one parental and one new strand.

Accepted Answer

Option A: Both true and R explains A. Semiconservative replication retains one old strand in each daughter DNA.

Question 15

Q15. Assertion (A): Mutation always produces harmful effects. Reason (R): Mutation changes DNA sequence.

Accepted Answer

Option C: A false R true. Mutations can be beneficial, neutral, or harmful.

Question 16

Q16. Case Study: A scientist observes that a bacterial population survives antibiotic treatment after repeated exposure. What is the most likely reason?

Accepted Answer

Option B: Natural selection of resistant mutants. Antibiotic-resistant bacteria survive and reproduce via natural selection.

Question 17

Q17. Case Study: In a food chain, grass → grasshopper → frog → snake, pesticides are found in highest concentration in snakes. This is due to:

Accepted Answer

Option B: Biomagnification. Toxic substances increase at higher trophic levels.

Question 18

Q18. Which enzyme cuts DNA at specific sequences producing sticky ends?

Accepted Answer

Option B: Restriction endonuclease. Restriction enzymes cut DNA at palindromic sites producing sticky ends.

Question 19

Q19. A population has allele frequency p = 0.7. What is q?

Accepted Answer

Option B: 0.3. p + q = 1 → q = 1 - 0.7 = 0.3

Question 20

Q20. In a dihybrid cross, the phenotypic ratio 9:3:3:1 is modified when:

Accepted Answer

Option B: Genes are linked. Linked genes do not assort independently, altering expected ratio.

Mock Test 04 Performance Solutions

Detailed Question Analysis

Q1. In DNA replication, which enzyme synthesizes short RNA primers?

Q2. In human evolution, increased brain size is mainly associated with:

Q3. Which of the following is NOT a part of innate immunity?

Q4. The correct sequence of nitrogen bases pairing in DNA is:

Q5. Which structure is responsible for transfer of genetic material during bacterial conjugation?

Q6. A test cross is performed to determine:

Q7. Which phase of meiosis is responsible for reduction of chromosome number?

Q8. Which of the following best describes ecological succession?

Q9. In biotechnology, plasmids are used because they:

Q10. Which molecule carries amino acids to ribosomes during protein synthesis?

Q11. Which contraceptive method prevents implantation?

Q12. A person suffering from AIDS is affected due to deficiency of:

Q13. Biomagnification is maximum in:

Q14. Assertion (A): DNA replication is semiconservative. Reason (R): Each daughter DNA contains one parental and one new strand.

Q15. Assertion (A): Mutation always produces harmful effects. Reason (R): Mutation changes DNA sequence.

Q16. Case Study: A scientist observes that a bacterial population survives antibiotic treatment after repeated exposure. What is the most likely reason?

Q17. Case Study: In a food chain, grass \(\rightarrow\) grasshopper \(\rightarrow\) frog \(\rightarrow\) snake, pesticides are found in highest concentration in snakes. This is due to:

Q18. Which enzyme cuts DNA at specific sequences producing sticky ends?

Q19. A population has allele frequency p = 0.7. What is q?

Q20. In a dihybrid cross, the phenotypic ratio 9:3:3:1 is modified when:

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Mock Test 04 Performance Solutions

Detailed Question Analysis

Q1. In DNA replication, which enzyme synthesizes short RNA primers?

Q2. In human evolution, increased brain size is mainly associated with:

Q3. Which of the following is NOT a part of innate immunity?

Q4. The correct sequence of nitrogen bases pairing in DNA is:

Q5. Which structure is responsible for transfer of genetic material during bacterial conjugation?

Q6. A test cross is performed to determine:

Q7. Which phase of meiosis is responsible for reduction of chromosome number?

Q8. Which of the following best describes ecological succession?

Q9. In biotechnology, plasmids are used because they:

Q10. Which molecule carries amino acids to ribosomes during protein synthesis?

Q11. Which contraceptive method prevents implantation?

Q12. A person suffering from AIDS is affected due to deficiency of:

Q13. Biomagnification is maximum in:

Q14. Assertion (A): DNA replication is semiconservative. Reason (R): Each daughter DNA contains one parental and one new strand.

Q15. Assertion (A): Mutation always produces harmful effects. Reason (R): Mutation changes DNA sequence.

Q16. Case Study: A scientist observes that a bacterial population survives antibiotic treatment after repeated exposure. What is the most likely reason?

Q17. Case Study: In a food chain, grass \(\rightarrow\) grasshopper \(\rightarrow\) frog \(\rightarrow\) snake, pesticides are found in highest concentration in snakes. This is due to:

Q18. Which enzyme cuts DNA at specific sequences producing sticky ends?

Q19. A population has allele frequency p = 0.7. What is q?

Q20. In a dihybrid cross, the phenotypic ratio 9:3:3:1 is modified when:

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