Question 1: Define a limiting factor in the context of photosynthesis.

Answer: A limiting factor is a factor that restricts or slows down the rate of photosynthesis when in short supply or suboptimal conditions.

Question 2: Describe how light intensity can act as a limiting factor for photosynthesis.

Answer: Light intensity affects the rate of photosynthesis because higher light provides more energy for the process; if light is weak, the rate decreases because the energy available is insufficient.

Question 3: Explain why increasing carbon dioxide concentration can increase the rate of photosynthesis up to a point.

Answer: Carbon dioxide is a raw material for photosynthesis; increasing its concentration provides more of the reactant, thus increasing the rate until other factors become limiting.

Question 4: What is the effect of temperature on the rate of photosynthesis, and why does it occur?

Answer: Temperature affects enzyme activity involved in photosynthesis; too low slows reactions, too high denatures enzymes, reducing the rate.

Question 5: Calculate the increase in the rate of photosynthesis if the initial rate is 10 units and it increases to 15 units after a change in a limiting factor.

Answer: Increase = 15 - 10 = 5 units

Question 6: In an experiment, increasing light intensity from 200 to 800 lux caused the rate of photosynthesis to increase from 20 to 60 units. What can you conclude about light as a limiting factor in this scenario?

Answer: Light was a limiting factor at lower intensities; increasing it increased the rate until it plateaued, indicating other factors may now limit the process.

Question 7: Identify three environmental conditions that could act as limiting factors for photosynthesis in a natural setting.

Answer: Low light levels, low carbon dioxide concentration, and low temperature.

Question 8: Design a simple experiment to investigate how temperature affects the rate of photosynthesis. Include the variables, control, and safety precautions.

Answer: Variable: Temperature; Control: Light intensity and carbon dioxide levels kept constant; Method: Place aquatic plants in water baths set at different temperatures, measure oxygen production; Safety: Handle hot water carefully, avoid burns, ensure proper ventilation.

Question 9: A scientist observes that increasing temperature beyond 35°C causes the rate of photosynthesis to decline. Explain the biological reason for this observation.

Answer: Higher temperatures denature enzymes involved in photosynthesis, reducing their efficiency and slowing the process.

Question 10: Interpret the following scenario: In a greenhouse, increasing the level of carbon dioxide from 0.03% to 0.1% results in a significant increase in plant growth. What does this suggest about the role of carbon dioxide in photosynthesis?

Answer: It suggests that carbon dioxide is a limiting factor for photosynthesis and that increasing its availability can enhance plant growth.