41) Carbon fixation is taking place when plants:

A) oxidize CO2.

B) incorporate CO2 into sugars.

C) ingest CO2.

D) produce CO2.

E) convert CO2 into ATP.

42) For every six carbon dioxide molecules fixed by the Calvin cycle, how many molecules of G3P exit the cycle?

A) one

B) two

C) three

D) six

43) How many carbon dioxide molecules are required to make one molecule of glucose?

A) two

B) three

C) six

D) eight

44) The sugar that first bonds with carbon dioxide in the Calvin cycle is:

A) 3-PGA.

B) G3P.

C) RuBP.

D) rubisco.

45) Sugars are created during:

A) aerobic respiration.

B) the Calvin cycle of photosynthesis.

C) the light reactions of photosynthesis.

D) anaerobic respiration.

46) During the Calvin cycle, plants:

A) fix CO2 into sugar.

B) create ATP.

C) oxidize H2O to oxygen.

D) convert solar energy to chemical energy.

47) Photorespiration is when:

A) plants use sugars by respiration.

B) plants produce sugars during photosynthesis.

C) the enzyme rubisco binds O2 during the Calvin cycle.

D) the enzyme rubisco binds CO2 during the Calvin cycle.

48) Photorespiration results in:

A) no change in the sugar being produced during photosynthesis.

B) more sugar being produced during photosynthesis.

C) less sugar being produced during photosynthesis.

D) sometimes more and sometimes less sugar being produced during photosynthesis.

49) Photorespiration occurs most on:

A) hot, dry days.

B) hot, humid days.

C) cool, cloudy days.

D) cold, dry days.

E) cloudy, rainy days.

50) During photorespiration, rubisco binds with ________ , and during photosynthesis, rubisco binds with ________.

A) oxygen; a six-carbon sugar

B) oxygen; a five-carbon sugar

C) CO2; oxygen

D) a five-carbon sugar; oxygen

E) oxygen; CO2 and a five-carbon sugar