2.3.1 Photosynthesis

Question 1

What is the photosynthesis equation?

Answer 1

light energy

carbon dioxide + water glucose + oxygen

Question 2

What happens during photosynthesis?

Answer 2

■ light energy is absorbed by a green substance
called chlorophyll, which is found in chloroplasts in
some plant cells and algae
■ this energy is used by converting carbon dioxide
(from the air) and water (from the soil) into
sugar (glucose)
■ oxygen is released as a by-product.

Question 3

How can the rate of photosynthesis be limited? Name 3 ways.

Answer 3

■ shortage of light
■ low temperature
■ shortage of carbon dioxide.

Question 4

What happens the the glucose produced in photosynthesis?

Answer 4

The glucose produced in photosynthesis may be
converted into insoluble starch for storage. Plant cells
use some of the glucose produced during
photosynthesis for respiration.

Question 5

What is the glucose used for? Name 3 ways.

Answer 5

■ to produce fat or oil for storage
■ to produce cellulose, which strengthens
the cell wall
■ to produce proteins.

Question 6

What is needed to produce proteins?

Answer 6

To produce proteins, plants also use nitrate ions that

are absorbed from the soil.