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Flashcards in Carbon reactions Deck (19):
1

What happens to atmospheric CO2 every year

>10% reduced to carbohydrate by photosynthetic organisms

2

How much nitrogen gas in atmosphere

78%

3

How much oxygen gas in atmosphere

21%

4

How much argon in atmosphere

1%

5

How much carbon dioxide in atmosphere

0.04% (trace gas)

6

Carbon reactions

Accelerate in presence of light but can occur without it - used NADPH and ATP from light reactions, take place in stromal matrix of chloroplast

7

How was Calvin Benson cycle discovered

By using 14CO2 in pulse-chase experiments - use 2D paper chromatographic techniques and radioautography comparisons made with organic compound controls- spots eluted from paper and identified with MS and IR spec.

8

When was radioactivity seen in PGA

After 5s in COOH, after 30s two other carbons became labelled

9

What is the CO2 acceptor

Expect 2C acceptor but instead 5C - ribulose-1,5-bisphosphate

10

What does calvin cycle require

ATP, NADPH, CO2, RuBP, RuBisCO

11

How many turns of the calvin cycle produces 1 glucose

6

12

Plant carbohydrate stores

1. Starch (amylose) similar to glycogen (chloroplasts) 2. Sucrose (cytosol)

13

How many ATPs used for six rounds of calvin cycle

18

14

How many ATps used for C4 Calcin cycle

30

15

What is the most abundant protein in nature

Rubisco

16

Role of magnesium and CO2

Mg2+ with CO2 at lysine --> carbamate. Activates bound RuBP so that it can react with substrate CO2

17

Photorespiration

Rubisco can't distinguish fully between CO2 and O2 - gets worse at higher temperatures

18

What does photorespiration produce

Phosphoglycolate (toxic) and 3-phosphoglycerate

19

How do we deal with the oxygenation problem

C4 pathway