Chapter 8 - Photosynthesis

Question 1

State the equation for photosynthesis [1]

Answer 1

6CO2 + 6H2O ——–> C6H12O6 + 6O2 [1]

Question 2

Which part of the leaf absorbs sunlight for photosynthesis and what does it contain? [1]

Answer 2

Chloroplasts [1]

Which contain chlorophyll [1]

Question 3

What are the 4 limiting factors for photosynthesis? [4]

Answer 3

• Temperature [1]
• CO2 conc. [1]
• Light intensity [1]
• Number of chlorophyll [1]

Question 4

Explain how low and high temperature can affect the rate of photosynthesis. [3]

Answer 4

Rate of photosynthesis is low as the reactant molecules have less kinetic energy [1]. At high temperatures, enzymes denature [1], which means they cannot speed up the reactions [1].

Question 5

State 3 uses of photosynthesis in plants. [3]

Answer 5

Respiration - Release energy [1]
Lipids for storage [1]
Cellulose - Strengthen cell walls [1]
Amino acids - Protein synthesis [1]

Question 6

What type of reaction is photosynthesis? [1]

Answer 6

Endothermic [1]

Question 7

Describe 4 adaptations of leaves for effective photosynthesis. [4]

Answer 7

• Large surface area for light to fall on [1]
• Thin leaves for quicker diffusion of gases [1]
• Guard cells to regulate gas exchange [1]
• Chloroplasts containing chlorophyll to absorb light [1]

Question 8

Explain how CO2 levels affect the rate of photosynthesis [2]

Answer 8

• Plants need CO2 to begin photosynthesis [1]

- which means if levels are low, photosynthesis rate decreases. [1]

Question 9

Describe how greenhouses control limiting factors to maximize photosynthesis [4]

Answer 9

Electricity and gas are used [1]
To control CO2 levels and light intensity [1]
Monitoring equipment [1]
To maintain plants conditions [1]