Chapter Exam

Chapter 13: Photosynthesis — Online MCQ Test

Q: Which pigment is known as the 'reaction center' in photosystem II?

Answer: A. P680 — P680 is the specialized pair of chlorophyll a molecules that acts as the reaction center in Photosystem II.

Q: The primary electron acceptor in non-cyclic photophosphorylation is:

Answer: B. Pheophytin — Pheophytin is the primary electron acceptor that receives electrons from excited P680.

Q: During the C3 cycle, the first stable compound formed after CO2 fixation is:

Answer: C. 3-phosphoglyceric acid — RuBP combines with CO2 to form two molecules of 3-PGA, a three-carbon compound.

Q: In the C4 cycle, which enzyme is responsible for the formation of oxaloacetic acid?

Answer: B. PEP carboxylase — PEP carboxylase has a high affinity for CO2 and facilitates the conversion of Phosphoenolpyruvate (PEP) to Oxaloacetate (OAA).

BOTANY · CLASS 11th · Tamil Nadu State Board

Practice Chapter 13: Photosynthesis with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 11th BOTANY. This chapter covers: Focusing on bioenergetics this chapter details photosynthetic pigments light reaction electron transport C3 C4 and CAM pathways. Students study photorespiration and environmental f.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 13: Photosynthesis — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 11th BOTANY — Chapter 13: Photosynthesis, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which pigment is known as the 'reaction center' in photosystem II?

A. P680 ✓
B. P700
C. Chlorophyll b
D. Carotenoids

Answer: A. P680
P680 is the specialized pair of chlorophyll a molecules that acts as the reaction center in Photosystem II.

The primary electron acceptor in non-cyclic photophosphorylation is:

A. Plastocyanin
B. Pheophytin ✓
C. Ferredoxin
D. Cytochrome b6f

Answer: B. Pheophytin
Pheophytin is the primary electron acceptor that receives electrons from excited P680.

During the C3 cycle, the first stable compound formed after CO2 fixation is:

A. Oxaloacetic acid
B. Phosphoglyceraldehyde
C. 3-phosphoglyceric acid ✓
D. Ribulose 1,5-bisphosphate

Answer: C. 3-phosphoglyceric acid
RuBP combines with CO2 to form two molecules of 3-PGA, a three-carbon compound.

Why is the cyclic photophosphorylation pathway considered 'cyclic'?

A. It uses only Photosystem II
B. Electrons released from P700 return to P700 after passing through an ETC ✓
C. It produces oxygen continuously
D. It fixes carbon in a loop

Answer: B. Electrons released from P700 return to P700 after passing through an ETC
In cyclic electron transport, electrons emitted by P700 pass through ferredoxin and cytochrome complexes before returning to P700.

In the C4 cycle, which enzyme is responsible for the formation of oxaloacetic acid?

A. RuBisCO
B. PEP carboxylase ✓
C. Malate dehydrogenase
D. Pyruvate phosphate dikinase

Answer: B. PEP carboxylase
PEP carboxylase has a high affinity for CO2 and facilitates the conversion of Phosphoenolpyruvate (PEP) to Oxaloacetate (OAA).

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