Y8 Science | Photosynthesis

Question 1

What is photosynthesis? (simple version)

Answer 1

How plants make food from sunlight

Question 2

What is photosynthesis (detailed version)

Answer 2

Building glucose from carbon dioxide and water using light

Question 3

Name one use of glucose in plants.

Answer 3

Respiration/Make and strengthen cellulose cell wall/Make starch for storage/Make lipids as energy store

Question 4

Where does photosynthesis occur in the cell?

Answer 4

Chloroplast

Question 5

Name the pigment in chloroplasts that absorbs light.

Answer 5

Chlorophyll

Question 6

State the word equation for photosynthesis

Answer 6

Carbon dioxide + water -> glucose + oxygen

Question 7

Is photosynthesis endothermic or exothermic?

Answer 7

Endothermic

Question 8

How does water enter plants?

Answer 8

Diffusion into root hair cells, transported through xylem

Question 9

Name the three organs in a plant

Answer 9

Roots, stem, leaf

Question 10

How do gases move in and out of plants?

Answer 10

Diffusion through tiny holes (stomata) on underside of leaf

Question 11

State an adaptation of the leaf for efficient photosynthesis.

Answer 11

Broad leaves/Thin/Have chlorophyll/Air spaces/Guard cells to regulate stomata opening/veins

Question 12

What is the function of the waxy cuticle?

Answer 12

To protect the leaf and reduce evaporation of water

Question 13

What is the function of the palisade cells in top layer of leaf??

Answer 13

To absorb light for photosynthesis

Question 14

What is the function of the spongy layer?

Answer 14

Creates spaces to allow CO2 to diffuse into the leaf

Question 15

State three ways that a leaf is adapted for gas exchange

Answer 15

Large surface area, thin, stomata

Question 16

Give an example of diffusion occurring in a plant

Answer 16

Gas exchange (oxygen and carbon dioxide)

Question 17

Define “transpiration”

Answer 17

Evaporation of water from a leaf

Question 18

How can you show a plant is photosynthesising?

Answer 18

Test it for starch (chains of glucose)

Question 19

What is starch?

Answer 19

An insoluble store of glucose

Question 20

How is starch formed in a plant?

Answer 20

During photosynthesis

Question 21

Which substance is used to test for the presence of starch?

Answer 21

Iodine solution

Question 22

What is the colour of iodine solution if starch is present?

Answer 22

Blue/black

Question 23

What are the stages for testing a leaf for starch?

Answer 23

boil leaf, add into boiling ethanol, spread onto white tile, add iodine to test for starch

Question 24

What minerals do plants need?

Answer 24

nitrates, phosphates, magnesium, potassium

Question 25

Where do plants get minerals from?

Answer 25

They are dissolved in water in the soil, absorbed through roots

Question 26

What happens to a plant if it doesn’t have enough nitrates?

Answer 26

poor growth, older leaves go yellow

Question 27

What happens to a plant if it doesn’t have enough phosphorous?

Answer 27

poor root growth, younger leaves go purple

Question 28

What happens to a plant if it doesn’t have enough potassium?

Answer 28

yellow leaves with dead patches (needed for healthy leaves)

Question 29

What happens to a plant if it doesn’t have enough magnesium?

Answer 29

plant leaves turn yellow (it is used to make chlorophyll)

Question 30

Why do farmers use fertilisers?

Answer 30

To make sure crops have enough nutrients