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

The first event in the Calvin cycle is the attachment of carbon dioxide to the five carbon RuBP molecule, which ____________.

  1. forms a six carbon molecule that immediately breaks down into two three carbon PGA molecules

  2. is a reaction assisted by large quantities of RuBP carboxylase enzyme

  3. decreases cell carbon dioxide levels that increases the diffusion gradient

  4. 1, 2 and 3 are correct

  5. immediately becomes a six carbon sugar that is the base for starch, sucrose, cellulose, etc.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Calvin cycle begins with CO2 fixation by RuBP carboxylase (Rubisco), forming an unstable 6-carbon intermediate that splits into two 3-carbon PGA molecules. This reaction is enzyme-assisted and helps maintain the diffusion gradient for CO2 uptake.

Multiple choice

A photosystem contains _________________.

  1. pigments, a reaction center and an electron acceptor

  2. ADP, phosphate and hydrogen ions (H+)

  3. protons, photons, and pigments

  4. cytochromes only

  5. both B and C are correct.

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

A photosystem is a functional unit in the thylakoid membrane consisting of an antenna complex (pigments), a reaction center, and a primary electron acceptor.

Multiple choice

Which of the following statements is not true about C3 and C4 plants?

  1. C3 plants are more successful in mild climates than C4 plants.

  2. C4 plants contain chloroplasts only in some parts of their mesophyll cells.

  3. C3 plants fix carbon dioxide in the mesophyll cells.

  4. C3 plants make glucose in the bundle sheath cells.

  5. The first carbon dioxide fixation product in a C4 plant is oxaloacetate.
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

What are the products of photosynthesis?

  1. Water and carbon dioxide

  2. Water and oxygen

  3. Oxygen and carbohydrate

  4. Carbohydrate and water

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The overall chemical equation for photosynthesis is 6CO2 + 6H2O + light energy -> C6H12O6 (carbohydrate) + 6O2 (oxygen).

Multiple choice

CAM photosynthesis ____________.

  1. is the same as C4 photosynthesis

  2. is an adaptation to cold environments in the southern hemisphere

  3. is prevalent in desert plants that close their stomata during the day

  4. occurs in plants that live in marshy areas

  5. stands for chloroplasts and mitochondria
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CAM plants open their stomata at night to take in CO2, which is stored as organic acids, and close them during the day to conserve water in arid environments.

Multiple choice

What organisms are capable of photosynthesis?

  1. Plants only

  2. Plants and algae only

  3. Plants and some bacteria only

  4. Plants, algae and some bacteria

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Photosynthesis is performed by photoautotrophs, which include plants, algae, and various bacteria like cyanobacteria.

Multiple choice

The absorption spectrum of chlorophyll ____________________.

  1. is not the same as that of carotenoids

  2. approximates the action spectrum of photosynthesis

  3. explains why chlorophyll is a green pigment

  4. all of these are correct

  5. shows that some colours of light are absorbed more than others
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The absorption spectrum of chlorophyll reflects its light-harvesting properties, which align with the action spectrum of photosynthesis, explain its green color, and show differential absorption of wavelengths.