Biology

Photosynthesis in Plants

1,508 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 regarding 'Photosystem I' is/are incorrect?

A. Photosystem I lies in outer surface of thylakoids. B. Reaction centre of Photosystem I is P680. C. It participates in both cyclic as well as non-cyclic phosphorylation. D. Molecular oxygen is evolved as a result of photolysis of water.

  1. A and B

  2. A and C

  3. A and D

  4. B and C

  5. B and D
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because reaction centre of PS I is P700 and no molecular oxygen is evolved in PS I. Molecular oxygen is evolved as a result of photolysis of water in PS II.

Multiple choice

Which of the following statements is/are not correct regarding photosynthesis?

P. Maximum photosynthesis takes place in green light. Q. Quantum yield of photosynthesis is 0.125. R. Energy conversion efficiency of photosynthesis is 66%. S. 90% of the total photosynthesis in the world is carried out by marine algae.

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. R and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because maximum photosynthesis takes place in red light, next best in blue light and in green light. Energy conversion efficiency of photosynthesis is 33%.

Multiple choice

Which of the following statements are incorrect regarding non-cyclic phosphorylation?

P. Oxygenic process Q. Only one light trapping system (PS I) is involved. R. No NADPH is synthesised. S. NADP acts as the last electron acceptor.

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because two light trapping systems (PS I and PS II) are involved in non-cyclic phosphorylation and NADPH is synthesised during non-cyclic phosphorylation.

Multiple choice

Which of the following matchings is incorrect?

  1. Ribulose l,5-bisphosphate → 3-phosphoglycerate: Rubisco

  2. 3-Phospho glycerate → Glycerate 1,3-bisphosphate: Phosphoglycerate kinase

  3. Dihydroxy acetone phosphate → Fructose 1,6-bisphosphate: Aldolase

  4. Xylulose 5-phosphate → Ribulose 5-phosphate: ribose-5-phosphate isomerase

  5. Ribulose 5-phosphate → Ribulose 1,5,- bisphosphate: Phosphoribulokinase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is wrong because conversion of xylulose 5-phosphate to ribulose 5-phosphate is catalysed by ribulose-phosphate epimerase, whereas conversion of ribose 5-phosphate to ribulose 5-phosphate is catalysed by ribose-5-phosphate isomerise.

Multiple choice

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

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

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

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

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

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

Correct answer is P680* → Pheophytin → Plastoquinone → Cytochrome b6-f complex → Plastocyanin → P 700.

Multiple choice

Match the columns:

 
Column – I Column – II
P. Emerson and Arnold 1. Oxygen comes from water in photosynthesis
Q. Ruben and Kamen 2. Chloroplasts as the site of photosynthesis
R. Arnon 3. Mechanism of phosphorylation in chloroplast
S. Engelmann 4. Existence of light and dark reaction in photosynthesis

  1. P - 2, Q - 1, R - 3, S - 4

  2. P - 2, Q - 3, R - 4, S - 1

  3. P - 3, Q - 1, R - 4, S - 2

  4. P - 3, Q - 4, R - 2, S - 1

  5. P - 4, Q - 2, R - 3, S - 1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because all are correctly matched. In 1932, Emerson and Arnold proved the existence of light and dark reaction in photosynthesis. In 1939, Samuel Ruben and Martin Kamen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water. In 1954, Arnon discovered the mechanism of phosphorylation in chloroplasts. In 1881, Theodore Engelmann identified chloroplasts as the site of photosynthesis.  

Multiple choice

Which of the following statements about dark reaction is/are incorrect?

P. Source of energy for dark reaction is ATP synthesised in light reaction. Q. Raw materials of dark reaction are water, ADP and H3PO4. R. Oxygen is a by-product of dark reaction and is released in the atmosphere. S. Dark reaction occurs in stroma of chloroplast.

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. R and S
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because water, ADP and H3PO4 are raw materials for light reaction. Raw materials of dark reaction are CO2, NADPH2 and ATP. Oxygen is a by-product of light reaction and is released in the atmosphere.

Multiple choice

Raw materials for light reaction are

  1. CO2, NADPH2 and ATP

  2. water, ADP and H3PO4

  3. NADP, H3PO4 and ADP

  4. NADPH2, ATP and O2

  5. hexose sugar
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because raw materials for light reaction are water, ADP and H3PO4.

Multiple choice

Which of the following statements are not true regarding C4 plants?

P. Carbon dioxide fixation occurs twice. Q. PEP acts as carbon dioxide acceptor in bundle sheath. R. Leaf anatomy is of Kranz type. S. They require 18 ATP for synthesis of one molecule of glucose.

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because phosphoenolpyruvate (PEP) acts as carbon dioxide acceptor in mesophyll cells and ribulose-1,5-bisphosphate (RuBP) in bundle sheath functions as carbon dioxide acceptor and C4 plants require 30 ATP molecules for synthesis of one molecule of glucose.

Multiple choice

Match the columns:

 
Column – I Column – II
P. Hill and Bendal 1. Z-scheme of light reaction
Q. Peter Mitchell 2. Chemiosmotic hypothesis of ATP synthesis in light reaction
R. Hatch and Slack 3. C3 pathway for CO2 fixation
S. Melvin Calvin 4. C4 pathway for CO2 fixation

  1. P - 1, Q - 2, R - 3, S - 4

  2. P - 2, Q - 1, R - 4, S - 3

  3. P - 3, Q - 2, R - 1, S - 4

  4. P - 4, Q - 3, R - 2, S - 1

  5. P - 1, Q - 2, R - 4, S - 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All are correctly matched.

Multiple choice

Which of the following pigments are capable to modulate light energy during the process of photosynthesis in plants?

  1. Chlorophyll b

  2. Chlorophyll a

  3. Carotenes

  4. Pheophytin

  5. Xanthophylls
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Xanthophylls are structural components of the light harvesting antenna in chloroplasts. They are yellow pigments xanthophylls are found in highest quantity in the leaves of most green plants, where they are capable to modulate light energy in photosynthesis.

Multiple choice

What is the name of the substance present in the leaves of the plant that enables them to prepare food?

  1. Stomata

  2. Chlorophyll

  3. Starch

  4. Carbohydrate

  5. Protein
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorophyll is a green pigment found in plants. It is often described as the 'green blood of plants. It plays a crucial role in producing food for green plants by synthesising simple sugars (glucose) from carbon dioxide and and water in the process of photosynthesis. 

Multiple choice

Which of the following statements about plants is true?

  1. Plants do not show movement.

  2. Plants cannot make their own food.

  3. Some plants reproduce by giving birth to young plants.

  4. Plants release oxygen during the process of photosynthesis.

  5. Plants breath through the process of respiration.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During the process of photosynthesis, plants release oxygen into the air. Plants use carbon dioxide, which they get from their leaves and water, from the roots and sunlight which they get from the sun in order to photosynthesise. The process of photosynthesising is when the plant uses its chlorophyll (that is what makes plants green) to change water, sunlight and carbon dioxide.