Photosynthesis questions

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Photosynthesis question collection

Review Photosynthesis questions for Biology, with correct answers shown and coverage across reactants and products of photosynthesis; chloroplasts and light absorption; limiting factors.

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Question 1

What is photosynthesis?
  1. A process where plants use light energy to make glucose
  2. A process where plants break down glucose to release energy
  3. A process where plants absorb oxygen through roots
  4. A process where plants convert proteins into minerals

Question 2

Which gas is taken in by leaves for photosynthesis?
  1. Carbon dioxide
  2. Oxygen
  3. Nitrogen
  4. Hydrogen

Question 3

Which substance is produced by photosynthesis and used as plant food?
  1. Glucose
  2. Starch
  3. Cellulose
  4. Chlorophyll

Question 4

Which gas is released by photosynthesis?
  1. Oxygen
  2. Carbon dioxide
  3. Methane
  4. Sulfur dioxide

Question 5

In which cell organelle does photosynthesis happen?
  1. Chloroplast
  2. Mitochondrion
  3. Nucleus
  4. Ribosome

Question 6

What is the role of chlorophyll?
  1. To absorb light energy
  2. To absorb mineral ions from soil
  3. To transport sugars in phloem
  4. To store oxygen in roots

Question 7

Which raw material for photosynthesis is absorbed from the soil?
  1. Water
  2. Glucose
  3. Oxygen
  4. Protein

Question 8

Which tissue transports water to leaves for photosynthesis?
  1. Xylem
  2. Phloem
  3. Epidermis
  4. Palisade layer

Question 9

Where does most photosynthesis occur in a leaf?
  1. Palisade mesophyll cells
  2. Lower epidermis
  3. Guard cells
  4. Phloem vessels

Question 10

Why are many palisade cells near the top of a leaf?
  1. They receive more light
  2. They absorb most water directly from air
  3. They release carbon dioxide for respiration
  4. They store all mineral ions permanently

Question 11

What is the function of stomata in photosynthesis?
  1. They allow carbon dioxide to enter the leaf
  2. They absorb water from the xylem
  3. They produce glucose directly
  4. They move sugars into the phloem

Question 12

Why does temperature affect the rate of photosynthesis?
  1. Photosynthesis is controlled by enzymes
  2. Temperature changes the amount of chlorophyll in each reaction
  3. Temperature supplies the carbon dioxide used in glucose
  4. Temperature replaces the light energy absorbed by leaves

Question 13

Why is a plant destarched before testing whether light is needed for photosynthesis?
  1. To remove previously stored starch
  2. To remove chlorophyll from its leaves
  3. To stop carbon dioxide entering
  4. To fill its leaves with glucose

Question 14

Where does most of a plant's dry mass come from?
  1. Carbon dioxide in the air
  2. Mineral ions in the soil
  3. Water absorbed by the roots
  4. Chlorophyll in the leaves

Question 15

Why does a covered part of a destarched leaf stay brown with iodine?
  1. It received no light to make starch
  2. It received extra carbon dioxide
  3. It made more chlorophyll
  4. It absorbed iodine before the test

Question 16

Why can farmers add carbon dioxide in some greenhouses?
  1. To increase photosynthesis and crop yield
  2. To reduce light absorption by leaves
  3. To stop water transport in xylem
  4. To prevent all respiration in plants

Question 17

Why is photosynthesis the start of most food chains?
  1. It stores light energy as chemical energy in biomass
  2. It releases chemical energy from glucose for consumers
  3. It converts mineral ions directly into animal protein
  4. It transfers heat energy from consumers into plants

Question 18

What can plants make using glucose from photosynthesis?
  1. Starch for storage
  2. Mineral ions from water
  3. Oxygen as the main storage molecule
  4. Carbon dioxide for transport in phloem

Question 19

Why does photosynthesis stop in darkness?
  1. No light energy is available
  2. Chlorophyll is converted into glucose
  3. Carbon dioxide becomes unavailable in darkness
  4. Respiration removes the plant’s chloroplasts

Question 20

Which word equation is correct for photosynthesis?
  1. \(\text{Carbon dioxide} + \text{water} \to \text{glucose} + \text{oxygen}\)
  2. \(\text{Glucose} + \text{oxygen} \to \text{carbon dioxide} + \text{water}\)
  3. \(\text{Carbon dioxide} + \text{oxygen} \to \text{glucose} + \text{water}\)
  4. \(\text{Water} + \text{glucose} \to \text{carbon dioxide} + \text{oxygen}\)

Question 21

Why does spongy mesophyll contain air spaces?
  1. To let gases diffuse through the leaf
  2. To carry water up from the roots
  3. To transport sugars away from the leaf
  4. To absorb most of the light energy

Question 22

Which tissue transports dissolved sugars away from leaves?
  1. Phloem
  2. Xylem
  3. Palisade mesophyll
  4. Epidermis

Question 23

What is produced by photosynthesis?
  1. Glucose and oxygen
  2. Carbon dioxide and water
  3. Protein and oxygen
  4. Nitrogen and glucose

Question 24

Which iodine colour shows that starch is present in a leaf?
  1. Blue-black
  2. Orange-brown
  3. Brick-red
  4. Lilac

Question 25

Why is a leaf's upper epidermis transparent?
  1. Light can reach the palisade cells
  2. Water can enter from the air
  3. Sugars can leave through the surface
  4. Roots can absorb more minerals

Question 26

Why do leaves have a large surface area?
  1. To absorb more light
  2. To reduce light absorption
  3. To increase the distance for gas exchange
  4. To prevent water leaving the leaf

Question 27

Which cells control the opening and closing of stomata?
  1. Guard cells
  2. Palisade cells
  3. Root hair cells
  4. Xylem cells

Question 28

Which organisms photosynthesise as well as plants?
  1. Algae
  2. Fungi
  3. Animals
  4. Viruses

Question 29

How does being thin help a leaf photosynthesise?
  1. Carbon dioxide has a short diffusion distance
  2. Chlorophyll becomes unnecessary
  3. Water enters through the upper surface
  4. Glucose diffuses directly from the air

Question 30

In photosynthesis, what is water’s role?
  1. Reactant
  2. Catalyst
  3. Light-absorbing pigment
  4. Gaseous product

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Review Photosynthesis questions for Biology, with correct answers shown and coverage across reactants and products of photosynthesis; chloroplasts and light absorption; limiting factors.

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