PHOTOSYNTHESIS

Question 1

What is ATP?

Answer 1

adenosine triphosphate - which is the high energy chemical that transfers chemical energy in cells.

Question 2

What are carbohydrates?

Answer 2

food group consisting of sugars, starch and cellulose. Carbohydrates are vital for energy in humans and are stored as fat if eaten in excess. In plants, carbohydrates are important for photosynthesis.

Question 3

What is chlorophyll?

Answer 3

The green chemical inside the chloroplasts of plant cells. It enables photosynthesis to take place.

Question 4

What is limiting factors?

Answer 4

A factor which, if in short supply limits or reduces the rate of photosynthesis, eg temperature, light intensity and carbon dioxide concentration.

Question 5

What is starch?

Answer 5

A type of carbohydrate. Plants can turn the glucose produced in photosynthesis into starch for storage, and turn it back into glucose when it is needed for respiration.

Question 6

What is sugar?

Answer 6

A simple carbohydrate

Question 7

word equation for photosynthesis

Answer 7

carbon dioxide + water —————-> sugar + oxygen

light reactions taking place in chlorophyll

Question 8

stages of photosynthesis

Answer 8

light reactions - Light energy absorbed by chlorophyll is converted into chemical energy. Some of this energy is used to split water into hydrogen and oxygen. Some of the chemical energy is used to make ATP

Hydrogen and ATP are both transferred to the second stage of photosynthesis.

Question 9

carbon fixation

Answer 9

The ATP is broken down to release energy which is used to combine hydrogen (from the light reactions) with carbon dioxide to produce sugar.

The reactions of carbon fixation are controlled by specific enzymes.

Hydrogen from stage one + carbon dioxide —> sugar

Question 10

the three uses of sugar made from photosynthesis

Answer 10

energy source, storage, structural carbohydrate