Chapter 20

Question 1

Calvin cycle (in plants) uses

Answer 1

NADPH to fix CO2 into F6P

Question 2

Calvin cycle consists of three stages

Answer 2

1. Fixation
2. Reduction
3. Regeneration

Question 3

Fixation

Answer 3

: CO2 is fixed by combining with ribulose 1,5-bisphosphate to form two molecules of 3PG

Question 4

Reduction

Answer 4

(part of gluconeogenesis) 3PG is converted to F6P

Question 5

Regeneration

Answer 5

Ribulose 1,5-bisphosphate is regenerated from 3C sugars so that more CO2 can be fixed

Question 6

All steps of Valvin cycle take place in

Answer 6

stroma of chloroplasts

Question 7

Calvin cycle

Answer 7

only in plants

Question 8

To be self-perpetuating, the cycle must repeat ____ to make on e F6P from CO2

Answer 8

6 times

Question 9

To regenerate the 5C sugar, the cell will

Answer 9

use some “generic” enzymes and interconvert various 3C, 4C, 5C, 6C and 7C sugars!

Question 10

Hexose phosphates are made from

Answer 10

phosphoglycerate

Question 11

Reduction: gluconeogenesis

Answer 11

Hexose phosphates are made from phosphoglycerate

Question 12

once we arrive at F6P, it can practically interconvert at will between

Answer 12

F6P, G6P and G1P

Question 13

“hexose monophosphate pool”

Answer 13

“pull” any one of these 3 hexose monophosphates

Question 14

Regeneration of Ribulose-1,5-bisphosphate

Answer 14

: Transketolase and aldolase enzymes

Question 15

Transketolase requires

Answer 15

vitamin B1 (thiamine pyrophosphate)

Question 16

Transketolase transfers

Answer 16

a 2C unit (COCH2OH) from a ketose to an aldose

Question 17

Aldolase

Answer 17

catalyzes an aldol ADDITION instead of an aldol CLEAVAGE

Question 18

Aldolase adds

Answer 18

DHAP to any (well… most) aldose.

Question 19

Aldolase is specific for

Answer 19

for DHAP but can use any aldehyde

Question 20

transketolase 9-carbon reaction

Answer 20

C6 + C3 = C5 + C4

Question 21

transketolase 9-carbon reaction short hand

Answer 21

old C(ketose) + C(aldose) <->
new C(ketose) + C(aldose)

Question 22

standard aldolase addition

Answer 22

3C + 4C <-> 7C

Question 23

transketolase 10-carbon reaction

Answer 23

C7 + C3 <-> C5 + C5