IGCSE Biology Topic 6: Plant Nutrition MCQs – 30 Practice Questions with Answers (Cambridge 0610)

Free practice for Cambridge IGCSE Biology 0610 on plant nutrition, with every question followed by a short worked explanation to help you check your understanding.

Photosynthesis: Process and Equations

Q1. What is photosynthesis?

  • (A) The process by which plants break down glucose to release energy under normal conditions in this type of cell
  • (B) The process by which plants absorb water through their roots
  • (C) The process by which plants lose water from their leaves
  • (D) The process by which plants synthesise carbohydrates from raw materials using light energy
Show Answer

Answer: D – Photosynthesis is the process by which plants synthesise carbohydrates from raw materials using energy from light.

Q2. Which raw materials does a plant need for photosynthesis?

  • (A) Glucose and oxygen
  • (B) Carbon dioxide and water
  • (C) Starch and cellulose in the system described
  • (D) Oxygen and sucrose
Show Answer

Answer: B – Carbon dioxide and water are the raw materials that are turned into carbohydrate during photosynthesis.

Q3. Which products are made during photosynthesis?

  • (A) Carbon dioxide and water
  • (B) Glucose and oxygen
  • (C) Starch and carbon dioxide
  • (D) Sucrose and nitrogen
Show Answer

Answer: B – Photosynthesis produces glucose, a carbohydrate, and releases oxygen.

Q4. What is the word equation for photosynthesis?

  • (A) Glucose + oxygen → carbon dioxide + water for the organism involved when the reaction takes place
  • (B) Starch + water → glucose + oxygen
  • (C) Carbon dioxide + oxygen → glucose + water
  • (D) Carbon dioxide + water → glucose + oxygen, in light and chlorophyll
Show Answer

Answer: D – The word equation is carbon dioxide + water → glucose + oxygen, in the presence of light and chlorophyll.

Q5. What is the balanced chemical equation for photosynthesis?

  • (A) 6CO2 + 6O2 → C6H12O6 + 6H2O
  • (B) 6CO2 + 6H2O → C6H12O6 + 6O2
  • (C) C6H12O6 + 6O2 → 6CO2 + 6H2O
  • (D) 6H2O + 6O2 → C6H12O6 + 6CO2
Show Answer

Answer: B – The balanced equation is 6CO2 + 6H2O → C6H12O6 + 6O2.

Q6. What is chlorophyll?

  • (A) A white pigment found in roots
  • (B) A green pigment found in chloroplasts
  • (C) A storage carbohydrate in seeds in most ordinary conditions
  • (D) A gas released by leaves
Show Answer

Answer: B – Chlorophyll is a green pigment found in chloroplasts.

Q7. What does chlorophyll do during photosynthesis?

  • (A) It transfers energy from light into energy in chemicals
  • (B) It absorbs water from the soil
  • (C) It opens and closes the stomata
  • (D) It carries sucrose in the phloem during the process described
Show Answer

Answer: A – Chlorophyll transfers energy from light into energy in chemicals, for the synthesis of carbohydrates.

Q8. Where does most photosynthesis take place in a plant?

  • (A) In the roots
  • (B) In the stem only
  • (C) In the leaves, inside chloroplasts
  • (D) In the flowers only in a typical living cell
Show Answer

Answer: C – Photosynthesis takes place mainly in the leaves, where chloroplasts containing chlorophyll are found.

Q9. A plant is kept in bright light with plenty of carbon dioxide and water. Which gas will it release most?

  • (A) Carbon dioxide
  • (B) Nitrogen
  • (C) Oxygen
  • (D) Hydrogen
Show Answer

Answer: C – Oxygen is a product of photosynthesis, so it is released when photosynthesis is taking place.

Q10. Which factor is not needed for photosynthesis to take place?

  • (A) Light energy
  • (B) Chlorophyll
  • (C) Carbon dioxide
  • (D) Nitrate ions
Show Answer

Answer: D – Light, chlorophyll, carbon dioxide and water are needed for photosynthesis, while nitrate ions are used afterwards to make amino acids.

Uses of Glucose, Mineral Ions and Limiting Factors

Q11. How may glucose made in photosynthesis be used at once in the plant?

  • (A) It is stored as cellulose
  • (B) It is changed into chlorophyll under the conditions described
  • (C) It is stored as nectar
  • (D) It is used in respiration to provide energy
Show Answer

Answer: D – Glucose can be used in respiration to provide energy for the plant.

Q12. In what form is carbohydrate stored as an energy store in a plant?

  • (A) As cellulose
  • (B) As starch
  • (C) As sucrose
  • (D) As nectar
Show Answer

Answer: B – Starch is the energy store formed from the carbohydrates made in photosynthesis.

Q13. What is cellulose used for in a plant?

  • (A) To build cell walls
  • (B) To attract insects for pollination
  • (C) To transport sucrose in the phloem
  • (D) To store energy in seeds
Show Answer

Answer: A – Cellulose made from photosynthetic products is used to build cell walls.

Q14. How is carbohydrate transported around a plant?

  • (A) As starch in the xylem
  • (B) As sucrose in the phloem
  • (C) As glucose in the xylem
  • (D) As cellulose in the phloem
Show Answer

Answer: B – Sucrose is the form of carbohydrate transported in the phloem.

Q15. Why do some plants produce nectar?

  • (A) To attract insects for pollination
  • (B) To store energy for winter
  • (C) To build stronger cell walls during the reaction described
  • (D) To absorb more light
Show Answer

Answer: A – Nectar is produced to attract insects for pollination.


Q16. Why are nitrate ions important to a plant?

  • (A) They are needed to make amino acids
  • (B) They are needed to make chlorophyll
  • (C) They are needed to open the stomata
  • (D) They are needed to absorb light
Show Answer

Answer: A – Nitrate ions are needed for making amino acids, which are then used to make proteins.

Q17. Why are magnesium ions important to a plant?

  • (A) They are needed to make amino acids
  • (B) They are needed to make cellulose
  • (C) They are needed to make chlorophyll
  • (D) They are needed to make nectar
Show Answer

Answer: C – Magnesium ions are needed for making chlorophyll.

Q18. A plant grown without nitrate ions grows poorly and has pale, weak growth. What best explains this?

  • (A) It cannot make amino acids and therefore proteins
  • (B) It cannot make chlorophyll from nitrate in an ordinary cell
  • (C) It cannot carry out respiration
  • (D) It cannot absorb light energy
Show Answer

Answer: A – Without nitrate ions the plant cannot make amino acids, so it cannot make the proteins needed for growth.

Q19. What is meant by a limiting factor in photosynthesis?

  • (A) A factor that is always in short supply
  • (B) A factor that stops photosynthesis completely during normal activity for this process in the conditions given
  • (C) The factor in shortest supply, which limits the rate even if other factors are plentiful
  • (D) A factor that only affects leaves in shade
Show Answer

Answer: C – The rate of photosynthesis is limited by whichever factor, such as light, carbon dioxide or temperature, is in shortest supply.

Q20. Light intensity is increased, but the rate of photosynthesis hardly changes. What is the most likely explanation?

  • (A) Light is the limiting factor
  • (B) Chlorophyll has run out completely under normal conditions in this type of cell
  • (C) Carbon dioxide concentration or temperature is limiting the rate
  • (D) The plant has stopped respiring
Show Answer

Answer: C – If another factor is in shortest supply, increasing light alone will not raise the rate much.

Leaf Structure and Experiments

Q21. Why is a large surface area an adaptation for photosynthesis?

  • (A) It reduces water loss
  • (B) It makes the leaf thicker in the system described
  • (C) It stops gas exchange
  • (D) It allows the leaf to capture more light
Show Answer

Answer: D – A large surface area lets the leaf capture more light energy for photosynthesis.

Q22. Why is it an advantage for most leaves to be thin?

  • (A) It stores more starch
  • (B) It prevents light reaching the palisade layer
  • (C) It gives a short diffusion distance for gases
  • (D) It increases water loss
Show Answer

Answer: C – Thin leaves keep the distance gases must diffuse short, so carbon dioxide reaches photosynthetic cells quickly.

Q23. Why do palisade mesophyll cells contain many chloroplasts?

  • (A) To store water
  • (B) To transport sucrose when the reaction takes place
  • (C) To absorb light energy near the upper surface
  • (D) To open the stomata
Show Answer

Answer: C – Palisade cells are packed with chloroplasts near the upper surface, where light is strongest.

Q24. What is the role of air spaces in the spongy mesophyll?

  • (A) To store starch
  • (B) To allow gases to diffuse to photosynthetic cells
  • (C) To block light from the lower epidermis for the organism involved
  • (D) To carry water from the roots
Show Answer

Answer: B – Air spaces in the spongy mesophyll let carbon dioxide and oxygen diffuse between cells.

Q25. What are stomata, and how are they controlled?

  • (A) Openings for gas exchange, opened and closed by guard cells
  • (B) Veins that carry water, controlled by the xylem
  • (C) Pigments that absorb light, controlled by chlorophyll in most ordinary conditions
  • (D) Storage cells, controlled by the cuticle
Show Answer

Answer: A – Stomata are openings for gas exchange, and guard cells open and close them.

Q26. What is the role of the cuticle on a leaf?

  • (A) To reduce water loss from the leaf surface
  • (B) To absorb light energy
  • (C) To carry sucrose away from the leaf during the process described
  • (D) To open the stomata
Show Answer

Answer: A – The waxy cuticle covers the leaf surface and reduces water loss.

Q27. How do xylem and phloem in a vascular bundle serve photosynthesis?

  • (A) Xylem carries sucrose away and phloem brings water in
  • (B) Both carry oxygen out of the leaf
  • (C) Xylem brings water in and phloem carries sucrose away
  • (D) Both store starch in the leaf
Show Answer

Answer: C – Xylem brings water to the leaf for photosynthesis, while phloem carries sucrose made in the leaf to other parts of the plant.

Q28. Why is the upper epidermis useful for photosynthesis?

  • (A) It is transparent, so light can pass through to the palisade layer
  • (B) It contains many chloroplasts
  • (C) It stores starch
  • (D) It opens and closes to control gas exchange in a typical living cell
Show Answer

Answer: A – The upper epidermis is transparent, allowing light to reach the palisade mesophyll below.

Q29. In a starch test, one part of a leaf is covered and the leaf is left in light, then tested with iodine. What is expected?

  • (A) The covered part turns blue-black and the uncovered part stays brown
  • (B) Both parts turn blue-black equally
  • (C) Neither part changes colour
  • (D) The uncovered part turns blue-black and the covered part stays brown
Show Answer

Answer: D – Only the uncovered part received light for photosynthesis, so only it made starch that stains blue-black with iodine.

Q30. An aquatic plant in light is placed in hydrogencarbonate indicator solution. What happens to the indicator, and why?

  • (A) It turns yellow, because carbon dioxide increases under the conditions described
  • (B) It stays red, because nothing changes
  • (C) It turns blue-black, because starch forms
  • (D) It turns purple, because photosynthesis uses up carbon dioxide
Show Answer

Answer: D – In light, photosynthesis uses carbon dioxide faster than respiration releases it, so carbon dioxide falls and the indicator turns purple.

Work through any questions you missed again, then revise those areas before moving on to the next topic.