Ch 10.2: Photosynthesis

Question 1

What happens on hot days?

Answer 1

plants close stomata, which conserves H2O but also limits photosynthesis and causes O2 to build up

Question 2

What are C3 plants?

Answer 2

most plants are C3 plants, in which the initial fixation of CO2, via rubisco, forms a three-carbon compound (3-phosphoglycerate)

Question 3

What happens in photorespiration?

Answer 3

rubisco binds with O2 instead of CO2, producing a two-carbon compound, and its costly since it consumes O2 and organic fuel without producing and ATP or sugar

Question 4

What are C4 plants?

Answer 4

they minimize the cost of photorespiration by incorporating CO2 into a four-carbon compound as the first product of the Calvin cycle (they partially close their stomata in hot weather)

Question 5

What are bundle-sheath cells?

Answer 5

cells arranged in tightly packed sheaths around the leaf veins and this is where photosynthesis is completed

Question 6

What are the three steps in the production of sugar in C4 plants?

Answer 6

1. the production of the four-carbon precursors is catalyzed by the enzyme PEP carboxylase in the mesophyll cells
2. The four-carbon compounds are exported to bundle-sheath cells through the plasmodesmata
3. Within the bundle-sheath cells, CO2 is released from the four-carbon compound and then used in the Calvin cycle

Question 7

What are crassulacean acid metabolism (CAM) plants?

Answer 7

they conserve water by opening their stomata at night, and incorporate CO2 into organic acids that are stored in the vacuoles, their stomata is then closed during the day, and CO2 is released from organic acids and used in the Calvin cycle