Biology

Photosynthesis in Plants

1,492 Questions

Photosynthesis is the biological process by which plants convert light energy into chemical energy. This page contains practice questions covering essential topics like chlorophyll, light reactions, and the pathways specific to plants. This material is crucial for medical entrance exams and academic assessments.

Chlorophyll and pigmentsLight reactionsCalvin cycleCAM plantsElectron transportPhotosynthesis factors

Photosynthesis in Plants Questions

Multiple choice

Which of the following statements are not correct about noncyclic photophosphorylation?

  1. Oxygenic process.
  2. Only one light trapping system (Photosystem I) is involved.
  3. NADPH is not synthesised.
  4. NADP acts as last electron acceptor.

  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Two light trapping systems (PS I and PS II) are involved in noncyclic photophosphorylation. NADPH is synthesised during noncyclic photophosphorylation.

Multiple choice

Which of the following photosynthetic pigments are not found in tracheophytes and charophyta?

  1. Chlorophyll a
  2. Chlorophyll b
  3. Chlorophyll c
  4. Phycobilins

  1. 1 and 2

  2. 2 and 3

  3. 2 and 4

  4. 3 and 4

  5. 2, 3 and 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chlorophyll c is found only in the photosynthetic members of the Chromista as well as the dinoflagellates. Phycobilins are water-soluble pigments and are therefore, found in the cytoplasm or in the stroma of the chloroplast. They occur only in Cyanobacteria and Rhodophyta.

Multiple choice

The correct sequence for flow of electrons from excited P680* (in PS II) to P700 (reaction centre of PS I) is ________________.

  1. P680* → Pheophytin → Plastoquinone → Cytochrome b6-f complex → Plastocyanin → P 700

  2. P680* → Pheophytin → Cytochrome b6-f complex → Plastoquinone → Plastocyanin → P 700

  3. P680* → Plastocyanin → Plastoquinone → Cytochrome b6-f complex → Pheophytin → P 700

  4. P680* → Plastoquinone → Pheophytin → Plastocyanin → Cytochrome b6-f complex → P 700

  5. P680* → Plastoquinone → Pheophytin → Cytochrome b6-f complex → Plastocyanin → P 700
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct sequence for flow of electrons from excited P680* (in PS I) to P700 (reaction centre of PS II) is P680* → Pheophytin → Plastoquinone → Cytochrome b6-f complex → Plastocyanin → P 700. The excited form of P680, designated as P680*, is rapidly photo oxidized as it passes an electron to pheophytin, which is the primary electron acceptor of PS II. Reduced pheophytin, then hands on the electron to reduce plastoquinone. From reduced plastoquinone, electrons are accepted by cytochrom b6-f complex which gets reduced in this process. From reduced Cytochrome, b6-f complex electrons are taken up by plastocyanin, which is thus reduced. From reduced plastocyanin, electrons are accepted by P700, reaction centre of PS I, which is thus reduced.

Multiple choice

Chlorophyll molecule is _____ shaped.

  1. top

  2. kite

  3. cylinder

  4. kidney
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The chlorophyll molecule has a head-and-tail structure, where the porphyrin head is often described as kite-shaped or square-like in diagrams.

Multiple choice

The hydrogen donor in bacterial photosynthesis is

  1. water

  2. hydrogen sulphide

  3. sulphuric acid

  4. ammonia
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Unlike oxygenic photosynthesis in plants, bacterial photosynthesis (such as in green and purple sulfur bacteria) uses hydrogen sulfide (H2S) as an electron donor instead of water.

Multiple choice

Respiration in plants

  1. results in the formation of vitamins

  2. is a characteristic of all living cells

  3. often requires carbon dioxide

  4. occurs only during day
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Respiration in plants is a characteristic of all living cells.

Multiple choice

When does Photosynthesis occur?

  1. Only during the daytime

  2. At night

  3. Every time

  4. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Photosynthesis requires light energy to convert carbon dioxide and water into glucose, so it occurs only during the daytime.