Chapter 8: Photosynthesis

Question 1

Define chloroplasts

Answer 1

organelles in which photosynthesis takes place

Question 2

Define chlorophyll

Answer 2

the green pigment contained in chloroplasts

Question 3

What are the products of carbon dioxide and water?

Answer 3

glucose and oxygen

Question 4

What is the glucose that is produced used for?

Answer 4

• some of the glucose is used immediately by the cells of the plant for respiration
• a lot of the glucose is converted to insoluble starch and stored

Question 5

Name 3 leaf adaptations

Answer 5

• broad, giving them a large surface area for light to shine on
• thin, so that the diffusion distances for the gases are short
• the have guard cells that open and close the stomata to regulate gas exchange

Question 6

How has algae adapted to photosynthesizing in water?

Answer 6

The large surface area absorbs carbon dioxide that is dissolved in the water around them

Question 7

How does light affect the rate of photosynthesis?

Answer 7

more light = more photosynthesis can take place

Question 8

How does temperature affect the rate of photosynthesis?

Answer 8

higher temperatures = the rate of photosynthesis increases
However, because photosynthesis is controlled by enzymes, temperatures that are too high (40-50ºC) can causes enzymes to become denatured.

Question 9

How does chlorophyll levels affect the rate of photosynthesis?

Answer 9

If the amount of chlorophyll in the plant is limited, less photosynthesis can take place.

Question 10

How does carbon dioxide concentration affect the rate of photosynthesis?

Answer 10

• Because the atmosphere is 0.04% CO2, CO2 is often a limiting factor
• the more carbon dioxide concentration, the faster the rate of photosynthesis.

Question 11

How do plants strengthen their cells walls?

Answer 11

they build up glucose into complex carbohydrates such as cellulose

Question 12

What is the issue with storing too much glucose in plants?

Answer 12

glucose is soluble in water, and so storing too much glucose could affect the water balance of the plant

Question 13

Why do plants store starch instead?

Answer 13

starch is insoluble in water, and so plants can store large amounts of starch in their cells

Question 14

Where can starch be found in plants?

Answer 14

• cells: provides an energy store when it is dark

- special storage areas (e.g. bulbs): helps them survive through winter