Photosynthesis in Higher Plants

Photochemical phase

Carbon fixation phase

Oxidative phase

Regenerative phase

Photosynthesis increases linearly

Breakdown of chlorophyll and decrease in photosynthesis

Stomata open wider

$CO_{2}$ fixation stops immediately

Carbon dioxide

Oxygen

Nitrogen

Hydrogen

$5-10 \mu m$ in length

$1-2 \mu m$ in length

$20-40 \mu m$ in length

$0.5-1 \mu m$ in length

Stroma, Grana

Grana, Stroma

Grana, Lumen

Lumen, Grana

Outer membrane

Stroma

Thylakoids/Grana

Inter-membrane space

1

2

3

4

Chlorophyll a

Chlorophyll b

Xanthophyll

Carotene

Collagen

RuBisCO

Insulin

Hemoglobin

PS I $\rightarrow$ PS II $\rightarrow$ $NADP^+$

Water $\rightarrow$ PS II $\rightarrow$ PS I $\rightarrow$ $NADP^+$

PS I $\rightarrow$ Water $\rightarrow$ PS II $\rightarrow$ ATP

PS II $\rightarrow$ $NADP^+$ $\rightarrow$ PS I $\rightarrow$ ATP

Calvin

Arnon

Priestley

Engelman

Zero

Once

Twice

Many times

18

24

30

38

Smaller with no grana

Larger with no grana

Smaller with many grana

Absent

$C_4$ pathway

$C_3$ pathway

$C_2$ pathway

Glyoxylate cycle

They start using oxygen for photosynthesis

Current atmospheric $CO_2$ levels are limiting for them

Higher $CO_2$ prevents them from ever wilting

Enriched $CO_2$ makes the temperature cooler

Only the most abundant factor

The factor that is at its most optimal level

The factor that is currently limiting the process

The age of the plant only

Because dark reactions occur at night

Because dark reactions are enzymatic and enzymes are temperature sensitive

Because light reactions do not involve any movement of electrons

Because chlorophyll only works in the cold