Lecture 20 - dark phase of photosynthesis

Question 1

What is process that occurs in dark phase

Answer 1

Calvin cycle

Question 2

What 2 things ae needed for this

Answer 2

ATP and NADPH
Both from the light dependent phase of the reaction

Question 3

What is main aim of it

Answer 3

Fixate co2 it more reduced forms of carbon ie carbohydrates

Question 4

Where does Calvin cycle occur

Answer 4

stroma of chloroplasts

Question 5

Key 3 phases

Answer 5

1. Fixation
2. Reduction
3. Regeneration

Question 6

what molecule fixates CO2 and via which enzyme

Answer 6

ribulose 1,5-bisphosphate (5C) fixates CO2 (1C) into 2 molecules of 3-phosphoglycerate (3C) via RuBisCo
(this is the rate limiting step)

Question 7

why is RuBisCo a shit ezyme

Answer 7

• slow (only 3 CO2 fixated / sec)
• sometimes it binds O2 by accident which is waste of energy
  hence why theres sm of it

Question 8

what does 3PG need to be converted to 1,3BPG

Answer 8

ATP (2 cuz 2 molecules of 3PG)

Question 9

what happens to 1,3BPG

Answer 9

reduced to glyceraldehyde 3-phosphate (G3P) with oxidation of NADPH

Question 10

how many moleculles of R1,5BP are needed for Calvin cycle to continue

Answer 10

3

Question 11

how many G3P are needed to regenerate the 3 R1,5BP

Answer 11

6 in total
5 out of those are used to regen 3 molecules of R15BP
1 is used to contribute to making of sugars

Question 12

in total, making 1 molecule of glucose requires how many CO2, ATP and NADPH

Answer 12

6CO2
18ATP and 12 NADPH (from the light reaction)

Question 13

what 3 things plants will convert glucose/fructose into

Answer 13

sucrose
starch
cellulose