1. In the Z-scheme of photosynthesis, the final electron acceptor of Photosystem I is:

  • A. Plastoquinone
  • B. Plastocyanin
  • C. Ferredoxin
  • D. Cytochrome b6f complex

Answer: C. Ferredoxin

Explanation: Electrons from Photosystem I are transferred to ferredoxin, which ultimately reduces NADP⁺ to NADPH via ferredoxin-NADP reductase.

2. Which soil order is typically associated with the highest natural fertility and a thick, dark mollic epipedon?

  • A. Aridisols
  • B. Mollisols
  • C. Oxisols
  • D. Ultisols

Answer: B. Mollisols

Explanation: Mollisols possess a thick, organic matter-rich mollic epipedon and are among the world's most productive agricultural soils.

3. Which molecular marker is based on the amplification of DNA using arbitrary primers through PCR?

  • A. RFLP
  • B. RAPD
  • C. AFLP
  • D. SSR

Answer: B. RAPD

Explanation: RAPD (Random Amplified Polymorphic DNA) uses short arbitrary primers to amplify random DNA segments through PCR.

4. Which of the following fungi is the causal organism of Karnal bunt of wheat?

  • A. Ustilago tritici
  • B. Tilletia indica
  • C. Puccinia striiformis
  • D. Bipolaris sorokiniana

Answer: B. Tilletia indica

Explanation: Karnal bunt of wheat is caused by Tilletia indica, a quarantine-significant fungal pathogen.

5. During DNA replication, the enzyme responsible for joining Okazaki fragments is:

  • A. DNA Helicase
  • B. DNA Polymerase I
  • C. DNA Ligase
  • D. Primase

Answer: C. DNA Ligase

Explanation: DNA ligase seals nicks between adjacent Okazaki fragments by forming phosphodiester bonds on the lagging strand.

6. Which irrigation scheduling method is based on the ratio of irrigation water depth to cumulative pan evaporation?

  • A. IW/CPE Ratio
  • B. Duty-Delta Method
  • C. Soil Moisture Depletion Method
  • D. Crop Coefficient Method

Answer: A. IW/CPE Ratio

Explanation: The IW/CPE approach schedules irrigation by applying a fixed depth of water after a predetermined amount of cumulative pan evaporation.

7. Which of the following insects exhibits complete metamorphosis (holometabolous development)?

  • A. Grasshopper
  • B. Aphid
  • C. Rice stem borer
  • D. Termite

Answer: C. Rice stem borer

Explanation: Rice stem borer undergoes egg, larva, pupa, and adult stages, characteristic of complete metamorphosis.

8. Which enzyme is responsible for converting pyruvate into acetyl-CoA before entry into the citric acid cycle?

  • A. Pyruvate carboxylase
  • B. Pyruvate dehydrogenase complex
  • C. Citrate synthase
  • D. Malate dehydrogenase

Answer: B. Pyruvate dehydrogenase complex

Explanation: The pyruvate dehydrogenase complex catalyzes oxidative decarboxylation of pyruvate to acetyl-CoA, linking glycolysis to the TCA cycle.

9. Which plant growth regulator is commercially used to induce parthenocarpic fruit development in tomato?

  • A. Abscisic acid
  • B. Indole-3-acetic acid (IAA)
  • C. Gibberellic acid (GA₃)
  • D. Ethylene

Answer: C. Gibberellic acid (GA₃)

Explanation: Gibberellic acid is widely used to induce seedless (parthenocarpic) fruit development in tomato and several other horticultural crops.

10. Which sampling technique gives every unit in the population an equal and independent chance of being selected?

  • A. Stratified sampling
  • B. Systematic sampling
  • C. Cluster sampling
  • D. Simple random sampling

Answer: D. Simple random sampling

Explanation: In simple random sampling, every population unit has an equal and independent probability of selection.