Gen. Bio. Quiz 2: Calvin Cycle Flashcards
The first scientist to discover the Calvin cycle that won him and his colleagues the Nobel Prize in Chemistry in 1961.
Melvin Calvin (University of Berkeley)
The apparatus in which the photosynthesis experiments are performed.
The “Lollipop” apparatus (The Bancroft Library)
Calvin Cycle.
a. Takes place in the ________
b. Uses ______ and __________ to reduce CO2 to sugar.
a. stroma
b. ATP; NADPH
What is reduced in the Calvin cycle to form sugar?
Carbon Dioxide (CO2)
The 3 main stages in the Calvin cycle:
CO2 Fixation
Reduction
Regeneration
CO2 enters the leaf through openings called _________
stomata
Stage 1.
a. Incorporates each CO2 molecule one at a time by attaching the 5-C sugar called ______________.
a. ribulose-1,5-biphosphate (RuBP)
Stage 1.
b. The enzyme that catalyzes the 1st step is called ____________.
RuBP carboxylase-oxygenase (RuBisCO)
Stage 1.
c. The product of the 1st step is ______________ that is short-lived because it is unstable and splits in half.
c. 6-carbon Intermediate
Stage 1.
d. After splitting, it forms TWO molecules of __________________.
d. 3-phosphoglycerate (3-PGA)
Stage 2.
a. Each 3-PGA receives a phosphate group from ATP becoming ______________.
b. After ATP enters, it also then releases _________ to the stroma.
a. 1,3-biphosphoglycerate
b. ADP
Stage 2.
c. TWO electrons from NADPH REDUCES 1,3-biphosphoglycerate losing its phosphate group, and becoming _________________.
d. After NADPH enters, it also then releases ____________ to the stroma.
c. glyceraldehyde 3-phosphate (G3P)
d. NADP+ and Pi
Stage 2.
e. For every 3 molecules of CO2 (meaning 3 repeats of the cycle), there are ____ molecules of _________ that are formed.
f. ____ molecule exits the cycle to be used by the ___________, but the other _____ must be recycled to regenerate the 3 molecules of RuBP.
e. 6 molecules; G3P
f. 1 molecule; plant cell; 5 molecules
Stage 3.
a. 5 molecules of G3P are REARRAGED by the last steps into ______________.
b. For this to happen, the cycle spends ________ (#) more molecules of ATP.
a. 3 molecules of RuBP
b. 3 more molecules of ATP
How many turns of the Calvin Cycle to make one G3P molecule that can exit the cycle?
3 turns
How much G3P is needed for one molecule of glucose?
2 G3P molecules
(Since 1 G3P contains three fixed carbon atoms and a glucose molecule has six-carbon atoms)
How many turns of the cycle to produce one molecule of glucose?
6 turns
Carbon.
_____ (#) CO2 combine with 3 RuBP acceptors, making 6 molecules of
glyceraldehyde-3-phosphate ( G3P) .
3 CO2
ATP.
_____ (#) ATP are converted to ____ (#) ADP.
9 ATP; 9 ADP
(6 during reduction, 3 during regeneration)
NADPH.
____ (#) NADPH are converted ____ (#) NADP+
6 NADPH; 6 NADP+
(during the reduction step)
To synthesize one glucose molecule, the Calvin cycle uses ________ molecules of CO2, ________ molecules of ATP, and ________ molecules of NADPH.
6 CO2
18 ATP
12 NADPH
