Gen. Bio. Quiz 2: Calvin Cycle

Question 1

The first scientist to discover the Calvin cycle that won him and his colleagues the Nobel Prize in Chemistry in 1961.

Answer 1

Melvin Calvin (University of Berkeley)

Question 2

The apparatus in which the photosynthesis experiments are performed.

Answer 2

The “Lollipop” apparatus (The Bancroft Library)

Question 3

Calvin Cycle.
a. Takes place in the ________
b. Uses ______ and __________ to reduce CO2 to sugar.

Answer 3

a. stroma
b. ATP; NADPH

Question 4

What is reduced in the Calvin cycle to form sugar?

Answer 4

Carbon Dioxide (CO2)

Question 5

The 3 main stages in the Calvin cycle:

Answer 5

CO2 Fixation
Reduction
Regeneration

Question 6

CO2 enters the leaf through openings called _________

Answer 6

stomata

Question 7

Stage 1.
a. Incorporates each CO2 molecule one at a time by attaching the 5-C sugar called ______________.

Answer 7

a. ribulose-1,5-biphosphate (RuBP)

Question 8

Stage 1.
b. The enzyme that catalyzes the 1st step is called ____________.

Answer 8

RuBP carboxylase-oxygenase (RuBisCO)

Question 9

Stage 1.
c. The product of the 1st step is ______________ that is short-lived because it is unstable and splits in half.

Answer 9

c. 6-carbon Intermediate

Question 10

Stage 1.
d. After splitting, it forms TWO molecules of __________________.

Answer 10

d. 3-phosphoglycerate (3-PGA)

Question 11

Stage 2.
a. Each 3-PGA receives a phosphate group from ATP becoming ______________.
b. After ATP enters, it also then releases _________ to the stroma.

Answer 11

a. 1,3-biphosphoglycerate
b. ADP

Question 12

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.

Answer 12

c. glyceraldehyde 3-phosphate (G3P)
d. NADP+ and Pi

Question 13

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.

Answer 13

e. 6 molecules; G3P
f. 1 molecule; plant cell; 5 molecules

Question 14

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.

Answer 14

a. 3 molecules of RuBP
b. 3 more molecules of ATP

Question 15

How many turns of the Calvin Cycle to make one G3P molecule that can exit the cycle?

Answer 15

3 turns

Question 16

How much G3P is needed for one molecule of glucose?

Answer 16

2 G3P molecules
(Since 1 G3P contains three fixed carbon atoms and a glucose molecule has six-carbon atoms)

Question 17

How many turns of the cycle to produce one molecule of glucose?

Answer 17

6 turns

Question 18

Carbon.
_____ (#) CO2 combine with 3 RuBP acceptors, making 6 molecules of
glyceraldehyde-3-phosphate ( G3P) .

Answer 18

3 CO2

Question 19

ATP.
_____ (#) ATP are converted to ____ (#) ADP.

Answer 19

9 ATP; 9 ADP
(6 during reduction, 3 during regeneration)

Question 20

NADPH.
____ (#) NADPH are converted ____ (#) NADP+

Answer 20

6 NADPH; 6 NADP+
(during the reduction step)

Question 21

To synthesize one glucose molecule, the Calvin cycle uses ________ molecules of CO2, ________ molecules of ATP, and ________ molecules of NADPH.

Answer 21

6 CO2
18 ATP
12 NADPH