Lesson 5.4 - Alternative Mechanisms of Carbon Fixation

Question 1

Define Stomata

Answer 1

Small pores in the surface of a leaf that can be opened and closed to control the exchange of gases between the atrmosphere and the leaf interior.

Question 2

What are small pores in the surface of a leaf that can be opened and closed to control the exchange of gases between the atrmosphere and the leaf interior known as?

Answer 2

Stomata

Question 3

Define Photorespiration

Answer 3

The catalysis of O₂ instead of CO₂ by rubisco into RuBP, which slows the Calvin cycle, consumes ATP, and results in a release of carbon.

Question 4

What is the catalysis of O2 instead of CO2 by rubisco into RuBP, which slows the Calvin cycle, consumes ATP, and results in a release of carbon known as?

Answer 4

Photorespiration

Question 5

Define C₄ Cycle

Answer 5

An alternate form of carbon fixation that some plants use, praticularly in hot weather, to increase the concentration of CO₂ available for the Calvin cycle reactions.

Question 6

What is an alternate form of carbon fixation that some plants use, praticularly in hot weather, to increase the concentration of CO₂ available for the Calvin cycle reactions known as?

Answer 6

C₄ Cycle

Question 7

Define Crassulacean Acid Metabolism (CAM)

Answer 7

A metabolic pathway, used mostly by succulent plants, in which the Calvin cycle and the C₄ cycle are separated in time for better efficiency of CO₂ fixation.

Question 8

What is a metabolic pathway, used mostly by succulent plants, in which the Calvin cycle and the C₄ cycle are separated in time for better efficiency of CO₂ fixation known as?

Answer 8

Crassulacean Acid Metabolism (CAM)

Question 9

O₂ can compete with CO₂ for the active site of the enzyme rubisco, reducing the efficiency of photosynthesis. The resulting pathway is called _____.

Answer 9

O₂ can compete with CO₂ for the active site of the enzyme rubisco, reducing the efficiency of photosynthesis. The resulting pathway is called photorespiration.

Question 10

Some plants have evolved a C₄ pathway as well as a physical arrangement and specialization of cells that bypass the problems of photorespiration. They do this by incorporating CO₂ into a _____-carbon compound in _____ cells and then transporting it to _____ cells.

Answer 10

Some plants have evolved a C₄ pathway as well as a physical arrangement and specialization of cells that bypass the problems of photorespiration. They do this by incorporating CO₂ into a 4-carbon compound in mesophyll cells and then transporting it to bundle-sheath cells.

Question 11

C₄ plants are significantly _____ efficient than C₃ plants in performing photosynthesis in warm and/or dry environments.

Answer 11

C₄ plants are significantly more efficient than C₃ plants in performing photosynthesis in warm and/or dry environments.

Question 12

Many cacti and succulent plants use crassulacean acid metabolism (CAM), which uses a C₄ cycle to fix carbon during the _____ and the Calvin cycle to produce carbohydrates during the _____.

Answer 12

Many cacti and succulent plants use crassulacean acid metabolism (CAM), which uses a C₄ cycle to fix carbon during the night and the Calvin cycle to produce carbohydrates during the day.