Photosynthesis_Esteemed STEM

Variations in Photosynthesis

Open Ended

1. How does photorespiration counter photosynthesis?

Open Ended

1. Describe how a C4 plant minimizes photorespiration.

Open Ended

1. How is the CAM pathway similar to C4 metabolism, and how is it different?

Multiple Choice

In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules.

• Sun

• Soil

• Carbon dioxide

• Chlorophyll

Multiple Choice

How does carbon dioxide enter the leaf?

• through the vascular system

• through the thylakoids

• through the chloroplasts

• through the stomata

Multiple Choice

Chlorophyll molecules are in which part of the chloroplast?

• Stroma

• Thylakoid membrane

• Stomata

• Thylakoid lumen

Multiple Choice

The reactions of the Calvin cycle are NOT directly dependent on light, but they usually do NOT occur at night. Why?

• At night, no water is available for the Calvin cycle.

• The Calvin cycle requires products only produced when the photosystems are illuminated.

• Carbon dioxide concentrations decrease at night.

• Plants usually open their stomata at night.

Multiple Choice

The Calvin cycle occurs in the __________.

• Stroma

• Matrix

• Stoma

• Thylakoid Membrane

Multiple Choice

Of the following, which occurs during the Calvin cycle?

• CO2 is reduced

• Photons are absorbed

• Excited electrons are conveyed from chlorophyll to an electron acceptor.

• ATP and NADPH are synthesized.

Multiple Choice

Rubisco is __________.

• the five-carbon sugar molecule that reacts with CO₂ to begin the Calvin cycle

• the enzyme in plants that captures CO₂ to begin the Calvin cycle

• the first stable intermediate in C₄ photosynthesis

• the enzyme responsible for splitting H₂O to produce O₂ in photosynthesis

Multiple Choice

In the Calvin cycle, CO₂ is combined with __________.

• two two-carbon compounds to form a five-carbon compound

• a two-carbon compound to form a three-carbon compound

• a five-carbon compound to form a stable six-carbon compound that can be converted directly to glucose

• a five-carbon compound to form an unstable six-carbon compound, which decomposes into two three-carbon compounds

Multiple Choice

Which of the following statements correctly describes the relationship between the light reactions and the Calvin cycle?

• The light reactions produce ATP and NADPH, both of which are used in the Calvin cycle.

• The light reactions produce carbon dioxide and water, both of which are used in the Calvin cycle.

• The light reactions produce carbon dioxide, ATP, and NADPH, all of which are used in the Calvin cycle.

• The light reactions produce water, ATP, and NADPH, all of which are used in the Calvin cycle.

Multiple Choice

Why are C₄ plants more suited to hot climates than C₃ plants?

• They suspend photosynthesis in the heat.

• Unlike C₃ plants, they keep fixing carbon dioxide even when the concentration of carbon dioxide in the leaf is low.

• They do not close their stomata in hot, dry weather.

• They evolved in cold weather but migrated to the tropics, where they were more suitable.