Question 1

Q1. Which nitrogenous base is present in RNA but absent in DNA?

Accepted Answer

Option B: Uracil. RNA contains uracil instead of thymine, which is present in DNA.

Question 2

Q2. The enzyme responsible for joining Okazaki fragments is:

Accepted Answer

Option B: DNA ligase. DNA ligase forms phosphodiester bonds between Okazaki fragments on lagging strand.

Question 3

Q3. Which Mendelian law explains separation of alleles during gamete formation?

Accepted Answer

Option B: Law of segregation. Alleles separate during gamete formation so each gamete carries one allele.

Question 4

Q4. The site of fertilization in human female reproductive system is:

Accepted Answer

Option C: Ampulla of fallopian tube. Fertilization usually occurs in the ampullary region of oviduct.

Question 5

Q5. Which structure acts as a physical and chemical barrier in innate immunity?

Accepted Answer

Option B: Skin. Skin prevents entry of pathogens and secretes antimicrobial substances.

Question 6

Q6. A tall pea plant with unknown genotype is crossed with a dwarf plant. This is used to determine:

Accepted Answer

Option B: Genotype of tall plant. Test cross reveals whether dominant trait is homozygous or heterozygous.

Question 7

Q7. During meiosis, independent assortment of chromosomes occurs in:

Accepted Answer

Option B: Metaphase I. Homologous chromosomes align randomly at equator in metaphase I.

Question 8

Q8. Which ecosystem component has the highest biomass in a forest?

Accepted Answer

Option C: Producers. Producers (plants) form maximum biomass at base of pyramid.

Question 9

Q9. Which is a correct use of plasmid in genetic engineering?

Accepted Answer

Option B: Gene cloning vector. Plasmids carry foreign DNA into host cells.

Question 10

Q10. The anticodon is found on:

Accepted Answer

Option C: tRNA. tRNA contains anticodon complementary to mRNA codon.

Question 11

Q11. Oral contraceptive pills mainly prevent pregnancy by:

Accepted Answer

Option B: Preventing ovulation. Hormonal pills inhibit ovulation by altering hormone levels.

Question 12

Q12. Which disease is caused by HIV?

Accepted Answer

Option B: AIDS. HIV destroys immune cells leading to Acquired Immunodeficiency Syndrome.

Question 13

Q13. In food chains, energy transfer between trophic levels is approximately:

Accepted Answer

Option B: 10%. Only ~10% energy is transferred; rest is lost as heat.

Question 14

Q14. Assertion (A): DNA replication occurs during S-phase of cell cycle. Reason (R): DNA synthesis ensures equal genetic material in daughter cells.

Accepted Answer

Option A: Both true and R explains A. S-phase is dedicated to DNA replication ensuring equal distribution.

Question 15

Q15. Assertion (A): Genetic drift is more significant in large populations. Reason (R): Random fluctuations affect allele frequencies more in small populations.

Accepted Answer

Option B: A false R true. Genetic drift is stronger in small populations, not large ones.

Question 16

Q16. Case Study: A farmer observes that insect-resistant Bt cotton reduces pesticide use significantly. What is the mechanism of resistance?

Accepted Answer

Option B: It produces Bt toxin. Bt gene produces toxin lethal to specific insect pests.

Question 17

Q17. Case Study: In a lake ecosystem, excessive fertilizers cause algal bloom followed by fish death. This process is called:

Accepted Answer

Option B: Eutrophication. Nutrient enrichment leads to oxygen depletion and ecosystem imbalance.

Question 18

Q18. Which enzyme is used to amplify DNA in PCR?

Accepted Answer

Option B: Taq polymerase. Taq polymerase is heat-stable and functions at high temperatures.

Question 19

Q19. If recombination frequency between two genes is 50%, they are:

Accepted Answer

Option C: Either on different chromosomes or far apart. 50% recombination indicates independent assortment.

Question 20

Q20. A population has genotype frequencies: AA = 0.49, Aa = 0.42, aa = 0.09. What is allele frequency of A?

Accepted Answer

Option C: 0.7. p = freq(AA) + ½ freq(Aa) = 0.49 + 0.21 = 0.70

Mock Test 05 Performance Solutions

Detailed Question Analysis

Q1. Which nitrogenous base is present in RNA but absent in DNA?

Q2. The enzyme responsible for joining Okazaki fragments is:

Q3. Which Mendelian law explains separation of alleles during gamete formation?

Q4. The site of fertilization in human female reproductive system is:

Q5. Which structure acts as a physical and chemical barrier in innate immunity?

Q6. A tall pea plant with unknown genotype is crossed with a dwarf plant. This is used to determine:

Q7. During meiosis, independent assortment of chromosomes occurs in:

Q8. Which ecosystem component has the highest biomass in a forest?

Q9. Which is a correct use of plasmid in genetic engineering?

Q10. The anticodon is found on:

Q11. Oral contraceptive pills mainly prevent pregnancy by:

Q12. Which disease is caused by HIV?

Q13. In food chains, energy transfer between trophic levels is approximately:

Q14. Assertion (A): DNA replication occurs during S-phase of cell cycle. Reason (R): DNA synthesis ensures equal genetic material in daughter cells.

Q15. Assertion (A): Genetic drift is more significant in large populations. Reason (R): Random fluctuations affect allele frequencies more in small populations.

Q16. Case Study: A farmer observes that insect-resistant Bt cotton reduces pesticide use significantly. What is the mechanism of resistance?

Q17. Case Study: In a lake ecosystem, excessive fertilizers cause algal bloom followed by fish death. This process is called:

Q18. Which enzyme is used to amplify DNA in PCR?

Q19. If recombination frequency between two genes is 50%, they are:

Q20. A population has genotype frequencies: AA = 0.49, Aa = 0.42, aa = 0.09. What is allele frequency of A?

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Mock Test 05 Performance Solutions

Detailed Question Analysis

Q1. Which nitrogenous base is present in RNA but absent in DNA?

Q2. The enzyme responsible for joining Okazaki fragments is:

Q3. Which Mendelian law explains separation of alleles during gamete formation?

Q4. The site of fertilization in human female reproductive system is:

Q5. Which structure acts as a physical and chemical barrier in innate immunity?

Q6. A tall pea plant with unknown genotype is crossed with a dwarf plant. This is used to determine:

Q7. During meiosis, independent assortment of chromosomes occurs in:

Q8. Which ecosystem component has the highest biomass in a forest?

Q9. Which is a correct use of plasmid in genetic engineering?

Q10. The anticodon is found on:

Q11. Oral contraceptive pills mainly prevent pregnancy by:

Q12. Which disease is caused by HIV?

Q13. In food chains, energy transfer between trophic levels is approximately:

Q14. Assertion (A): DNA replication occurs during S-phase of cell cycle. Reason (R): DNA synthesis ensures equal genetic material in daughter cells.

Q15. Assertion (A): Genetic drift is more significant in large populations. Reason (R): Random fluctuations affect allele frequencies more in small populations.

Q16. Case Study: A farmer observes that insect-resistant Bt cotton reduces pesticide use significantly. What is the mechanism of resistance?

Q17. Case Study: In a lake ecosystem, excessive fertilizers cause algal bloom followed by fish death. This process is called:

Q18. Which enzyme is used to amplify DNA in PCR?

Q19. If recombination frequency between two genes is 50%, they are:

Q20. A population has genotype frequencies: AA = 0.49, Aa = 0.42, aa = 0.09. What is allele frequency of A?

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