4.4.1.2 Rate of Photosynthesis

Question 1

What are the limiting factors that affect the rate of photosynthesis?

Answer 1

• intensity of light
• concentration of carbon dioxide
• temperature
• chloroplasts

Question 2

What are the effects of temperature on the rate of photosynthesis?

Answer 2

• enzymes needed for photosynthesis work slower is the temperature is too low
• if the plant gets too hot, enzymes needed for photosynthesis and other reactions are damaged (45°C)
• in winter, temperature if often the limiting factor

Question 3

What are the effects of light intensity on the rate of photosynthesis?

Answer 3

• light provides energy needed for photosynthesis
• if light level increases, rate of photosynthesis steadily increases but to a point
• at night, light intensity is the limiting factor

Question 4

What are the effects of carbon dioxide concentration on the rate of photosynthesis?

Answer 4

• carbon dioxide is needed for photosynthesis
• amount of carbon dioxide increases will only increase rate of photosynthesis to a point
• if there is enough light and temperature, then carbon dioxide is the limiting factor

Question 5

What are the effects of the amount of chlorophyll on the rate of photosynthesis?

Answer 5

• more chlorophyll means that they can absorb more light which increases photosynthesis
• the amount can be affected by disease or environmental stress

Question 6

How do you tell that a factor is limiting?

Answer 6

• the line doesn’t increase/plateaus/decreases the most

Question 7

What is inverse proportion?

Answer 7

• if one factor increases, the other decreases

Question 8

What is the inverse square law?

Answer 8

• the intensity of light is inversely proportional to the square distance from the source

Question 9

How is light intensity calculated?

Answer 9

• 1/distance*distance
• measured in arbitrary units

Question 10

What is the most common way to artificially create the ideal environment for plants to grow in?

Answer 10

• greenhouse

Question 11

How do greenhouses help maximise temperature without it becoming a limiting factor?

Answer 11

• trap sun’s heat
• heater in winter
• shades and ventilation in summer

Question 12

How do greenhouses help maximise light without it becoming a limiting factor?

Answer 12

• artificial light after sun goes down

Question 13

How do greenhouses help maximise carbon dioxide without it becoming a limiting factor?

Answer 13

• paraffin heater, as it burns it makes carbon dioxide as a by-product

Question 14

What are the benefits of greenhouses?

Answer 14

• easy to gain profit if plants given the right conditions to grow fast enough