Light dependent stage for plants

Question 1

Photons of what colour are most effective for photosynthesis and why?

Answer 1

Blue and red light are most effective because photosynthetic pigments can absorb between those 2 in the light spectrum

Question 2

What photosynthetic pigments can photo-systems contain?

Answer 2

.Chlorophyll A
.Chlorophyll B
.Carotene

Question 3

Function of stroma and grana:

Answer 3

Stroma -

Contains enzymes that catalyses reactions of photosynthesis

Grana -

Large surface area maximizes the number of photo-systems and the rate of light absorption

Question 4

What does the photon absorbed in photosystem II cause?

Answer 4

An excited electron which leaves and goes to an electron transport chain

Question 5

How is the excited electron replaced?

Answer 5

Breaking down of water (photolysis) by a water splitting enzyme to produce 2 electrons, replacing the ones that left photosystem II

Question 6

What else does photolysis produce?

Answer 6

Oxygen molecule and 2 H+ ions

Question 7

What is photophosphorylation?

Answer 7

As the electron moves along transport chain it loses energy, this energy is released to generate ATP, not directly though.

Question 8

How is ATP produced then?

Answer 8

-Energy used to actively transport H+ ions from stroma to thylakoid membrane
-Creates H+ gradient so it diffuses back to stroma through ATP synthase complex (chemiosmosis), which generates ATP.

Question 9

How is NADP reduced to NADPH?

Answer 9

-2 electrons from photosystem I added
-H+ ion from photolysis added