Quiz Chapter 2: Leaf Structure and Function

1. How does an increase in wind speed affect the rate of transpiration in a terrestrial plant?

1. Decreases transpiration by increasing atmospheric humidity near stomata.
2. Increases transpiration by sweeping away accumulated water vapor surrounding stomata.
3. Completely stops transpiration by triggering immediate stomatal closure.
4. Has zero impact on the diffusion gradient of water vapor.

2. In the Calvin cycle, what enzyme catalyzes the fixation of carbon dioxide to Ribulose 1,5-bisphosphate (RuBP)?

1. ATP synthase
2. RuBisCO
3. DNA polymerase
4. Amylase

3. What structural feature of thylakoids inside chloroplasts increases light absorption efficiency?

1. Their arrangement into stacked structures called grana
2. Thick lignified secondary cell wall reinforcements
3. Large central water vacuoles inside each disc
4. Presence of perforated sieve plates across their membranes

4. Which structural feature of guard cells causes them to curve outward when turgid, opening the stoma?

1. Outer cell walls are thicker and less elastic than inner cell walls.
2. Inner cell walls facing the pore are thicker and less flexible than outer walls.
3. Guard cells lack cell walls entirely on their lateral surfaces.
4. Chloroplasts exert mechanical outward push against cell membranes.

5. What is the primary role of photolysis of water during the light-dependent phase of photosynthesis?

1. Directly fixing carbon dioxide into triose phosphate
2. Replacing lost electrons in chlorophyll and releasing hydrogen ions (H+) and oxygen gas
3. Actively pumping potassium ions across guard cell membranes
4. Regenerating Ribulose 1,5-bisphosphate (RuBP)

6. At the compensation point, what is the net rate of gas exchange between the leaf and the surrounding atmosphere?

1. Maximum intake of carbon dioxide
2. Maximum release of oxygen gas
3. Zero net exchange of carbon dioxide and oxygen
4. Continuous rapid release of water vapor only

7. How does the thinness of a leaf lamina adapt it for efficient photosynthesis?

1. It increases mechanical resistance against strong wind gusts.
2. It shortens the diffusion distance for gases like CO2 to reach inner mesophyll cells.
3. It prevents water loss completely without requiring a waxy cuticle.
4. It allows phloem to transport minerals without expenditure of ATP.

8. Which phytohormone induces stomatal closure during severe soil water deficit or drought stress?

1. Auxin
2. Gibberellin
3. Abscisic acid (ABA)
4. Cytokinin

9. What chemical products generated during the light-dependent stage are required to drive the Calvin cycle in the stroma?

1. Oxygen and glucose
2. ATP and NADPH
3. Water and carbon dioxide
4. RuBP and RuBisCO

10. Where do light-dependent reactions of photosynthesis specifically take place inside the chloroplast?

1. Stroma matrix
2. Thylakoid membrane
3. Outer chloroplast membrane
4. Intermembrane space