Essential life processes in plants: Practice Questions

During a bright sunny day, a healthy plant leaf is actively performing photosynthesis. Which of the following statements accurately describes the net exchange of gases between the leaf and the atmosphere?

Root hair cells are highly adapted for absorbing water from the soil. Which structural feature of root hair cells significantly increases their efficiency in water uptake?

Suppose a plant is kept in an environment with high light intensity but is sprayed with a chemical that triggers full stomatal closure to prevent transpiration. How would this specifically affect the relationship between the light-dependent and light-independent reactions?

Which of the following is not a direct requirement for the process of photosynthesis in plants?

A plant is placed in a sealed chamber where the humidity is gradually increased while light intensity and temperature remain constant. What would be the most likely effect on the rate of transpiration?

Explain how cell turgidity provides mechanical support to the stems of young herbaceous plants.

Explain how wilting can be considered a survival strategy for a herbaceous plant when the rate of transpiration exceeds the rate of water absorption from the soil.

A young herbaceous plant relies on two primary mechanisms for structural support: cell turgidity and the physical nature of xylem vessels. Explain how each of these mechanisms individually contributes to the plant's upright posture and how they might complement each other.

Green plants convert light energy into chemical energy stored in glucose, which is then often converted into starch for storage in the leaves.

(a) Describe the chemical test used to detect the presence of starch in a leaf, including the name of the reagent and the color change observed for a positive result. (2 points)

(b) During the preparation of the leaf for this test, the leaf is boiled in water for a few minutes. Explain the biological purpose of this step. (2 points)

A potometer is a common laboratory apparatus used to measure the rate of water uptake by a leafy shoot under different environmental conditions.

(a) Explain why the leafy shoot must be cut underwater and why the entire apparatus must be air-tight to ensure accurate measurements. (2 points)

(b) Describe how an increase in wind speed influences the concentration gradient of water vapor around the stomata and how this subsequently affects the rate of transpiration. (3 points)