Unit 3 - Photosynthesis

Question 1

What is the first stage of photosynthesis called?

Answer 1

Light reactions

Question 2

What is the second stage of photosynthesis called?

Answer 2

Carbon fixation

Question 3

Describe what happens in the light reactions stage of photosynthesis?

Answer 3

-Light energy from the sun is captured by chlorophyll which is found inside chloroplasts
-This light energy is converted into chemical energy which is used to generate ATP
-Water that has been absorbed from soil into plants is split to produce hydrogen and oxygen molecules
-Oxygen diffuses into the atmosphere
-Carbon dioxide is passed on to stage two

Question 4

Describe what happens in the carbon fixation stage of photosynthesis?

Answer 4

-Carbon fixation is a series of enzyme controlled reactions
-Hydrogen and ATP created in the light reactions are now used during carbon fixation
-Hydrogen and ATP react with carbon dioxide from the atmosphere to form glucose

Question 5

What can glucose be used for after photosynthesis?

Answer 5

-Broken down and used by plant in respiration to provide energy for cell processes
-Built into long chains of cellulose, a structural carbohydrate used to build cell walls
-Linked into long chains of starch to be used as a storage carbohydrate for energy when needed

Question 6

What are the limiting factors of photosynthesis?

Answer 6

-Carbon dioxide concentration
-Light intensity
-Temperature

Question 7

What is chlorophyll?

Answer 7

The green pigment found in chloroplasts that absorbs light energy for photosynthesis