B8 - Photosynthesis

Question 1

What kind of reaction is photosynthesis?

Answer 1

Endothermic

Question 2

Symbol equation for photosynthesis?

Answer 2

6CO2 + 6H20 ~ C6H12O6 + 6O2

Question 3

How are leaves adapted for photosynthesis? (6)

Answer 3

• Broad = Large SA for light to fall on
• Thin = diffusion distances for gases are short
• Contain chlorophyll to absorb light
• Veins to bring water and remove produce of photosynthesis (xylem + phloem)
• Air spaces to allow CO2 to get to cells and oxygen to leave by diffusion
• Guard cells open and close stomata to regulate gas exchange.

Question 4

Limiting factors of photosynthesis?

Answer 4

Light, temperature, CO2 concentration and amount of chlorophyll

Question 5

Equation for light intensity?

Answer 5

Light intensity = 1/distance^2

Question 6

What do plants convert spare glucose into?

Why?

Answer 6

Starch.

Because it’s insoluble.

Question 7

Uses of glucose for a plant?

Answer 7

• Converted to lipids (fats and oils) to be stored or used to make cell membranes
• Converted to cellulose to strengthen cell walls
• Converted to amino acids for protein synthesis
• Converted to sucrose and stored in fruits
• Converted to nucleic acids for DNA
• Used in respiration to release energy

Question 8

Inverse square law of light?

Answer 8

If the distance is doubled, the intensity is reduced by 4 times.

If distance is trebled, the intensity is reduced by 9 times