Bioenergetics: Practice Questions

In the process of photosynthesis, what is the role of the green substance called chlorophyll?

A plant is grown in a greenhouse where the temperature is kept at \(25^{\circ}\text{C}\) and there is a high concentration of carbon dioxide. However, the rate of photosynthesis remains low. Which factor is most likely the limiting factor in this situation?

In humans, anaerobic respiration occurs when oxygen supply to the muscles is insufficient. Which of the following statements correctly evaluates the process of anaerobic respiration compared to aerobic respiration?

Aerobic respiration occurs continuously in both plants and animals. In which part of the cell do most of the chemical reactions for aerobic respiration take place?

A student observes that during vigorous exercise, the human body undergoes several physiological changes. Which of the following is not a direct change caused by the increased demand for energy during exercise?

Plants often produce glucose during photosynthesis and then convert it for various uses. Identify the specific mineral ion that plants must absorb from the soil to combine with glucose to produce proteins.

A student observes that during vigorous physical activity, their muscles begin to feel fatigued and eventually stop contracting efficiently.

Explain what metabolic substance builds up in the muscle tissue to cause this fatigue, and name the physiological requirement needed to later remove this substance from the body.

State the balanced chemical equation for aerobic respiration in cells.

Plants are able to use energy from the Sun to generate complex food molecules through the process of photosynthesis.

a) Write the balanced symbol equation for photosynthesis, which results in the production of glucose (\( C_6H_{12}O_6 \)).
b) The rate of photosynthesis can be limited by various environmental factors. Explain the term limiting factor and describe how temperature affects the rate of this process in terms of enzyme activity.
c) Glucose produced during photosynthesis has several uses in a plant. Name the larger molecule used for storage and explain why plants require nitrate ions from the soil to produce proteins.

A student investigated the effect of light intensity on the rate of photosynthesis in Elodea (waterweed). They used the following setup:
• A 10 cm piece of Elodea was placed in a beaker of water containing sodium hydrogen carbonate.
• A lamp was placed at a distance of 10 cm from the beaker.
• The number of bubbles released by the plant in one minute was recorded.
• This was repeated at distances of 20 cm, 30 cm, 40 cm, and 50 cm.

(a) State the independent variable and one control variable in this investigation. (2)

(b) The student noticed that at a distance of 10 cm, the rate of photosynthesis did not increase further even when the lamp was moved closer. Explain why, in terms of limiting factors. (2)

(c) The glucose produced during photosynthesis can be converted into several different substances within the plant. Describe two ways the plant uses this glucose, other than for respiration. (2)

(d) Explain why the student added sodium hydrogen carbonate to the water. (1)