Test 5
In the Calvin cycle, for every SIX carbon dioxide molecules that are incorporated into a carbohydrate such as glucose, _____ molecules of ATP are hydrolyzed and _____ molecules of NADPH are oxidized.
18, 12
The Calvin cycle can be very energy-expensive. How many molecules of ATP and NADPH respectively are required to incorporate one carbon dioxide molecule into the six-carbon sugar being formed?
3 ATP and 2 NADPH
Why do hot and dry conditions favor photorespiration?
Because plants close their stomata, inhibiting CO2 uptake and increasing O2
Why does CO2 enter CAM plants at nighttime?
Because the stomata of CAM plants are only open at night
How do CAM plants avoid water loss?
CAM plants close their stomata during the day and open them at night.
Which of the following plants are CAM plants?
Cacti, pineapple
Which of the following are products of the light reactions of photosynthesis that are used as reactants in the Calvin cycle?
NADPH and ATP
The process of photorespiration consumes ______ and produces ______.
O2 and CO2
RuBP carboxylase/oxygenase, also known as _____, is the most abundant protein in chloroplasts.
Rubisco
What enzyme is responsible for carbon fixation?
Rubisco
What happens during photorespiration?
Rubisco attaches O2 to RuBP, and CO2 is produced.
In CAM plants, the Calvin cycle occurs:
during the day
The incorporation of carbon from CO2 in the atmosphere into an organic molecule is called carbon .
fixation
Which of the following conditions affect the way the Calvin cycle operates in photosynthetic organisms?
light intensity, temperature, water availability
In hot dry conditions, rubisco can attach O2 to RuBP in a process called ______. which ultimately produces CO2.
photorespiration
The G3P produced at the end of the second phase of the Calvin cycle is directly used for which of the following?
regenerate ribulose bisphosphate make glucose or other carbohydrates
After glucose molecules are synthesized, they can be linked together to form a polymer called _____, which is stored, or used to make the disaccharide _____, which can be transported to other parts of the plant.
starch and sucrose
The glucose that is made by plant cells can be converted to other carbohydrates, including:
starch and sucrose
The Calvin cycle is affected by certain environmental conditions, including light intensity, _____ availability, and _____.
water temperature
Which of the following occur during hot and dry conditions?
- Rubisco'w oxidation activity is favored - Stomata close and reduce the intake of CO2 - Oxygen builds up in leaves
True or false: The term "C3" was derived from the 3-carbon sugar that represents the end product of photosynthesis.
False, A three carbon molecule
True or false: Glucose is the primary output of the Calvin cycle.
False. The primary output of the Calvin cycle is glyceraldehyde-3-phosphate, which can be used for glucose synthesis in another set of reactions.