OCR 5.6 Photosynthesis

Question 1

What is the granum?

Answer 1

inner part of the chloroplast made of stacks of thylokoid membranes, where the light dependent stage takes place

Question 2

What is a photosystem?

Answer 2

a group of photosynthetic pigments in the thylakoids that trap photons

Question 3

What is the stroma?

Answer 3

fluid filled matrix of chloroplasts, where the light dependent stage takes place

Question 4

What is a thylakoid?

Answer 4

flattened membrane-bound sac found inside the chloroplasts; contains photosyntheitc pigments and photosytems and is the site of the light dependent reaction.

Question 5

Where does the light dependent stage take place?

Answer 5

stroma

Question 6

What wavelength of light does PS2 absorb?

Answer 6

680nm

Question 7

What wavelength of light does PS1 absorb?

Answer 7

700nm

Question 8

What wavelengths of light do carotenoids absorb?

Answer 8

400-500nm

Question 9

What wavelengths of light do Xanthophylls absorb?

Answer 9

375-550nm

Question 10

What wavelengths of light do chlorophyll b absorb?

Answer 10

400-500nm & 640nm

Question 11

What wavelengths of light do chlorophyll a absorb?

Answer 11

680/700nm & 440nm

Question 12

Why do most plants appear green?

Answer 12

Because they do not absorb green light (no photsynthtic pigments in that range

Question 13

How do you calcluate Rf values?

Answer 13

distance traveled by pigment / distance travelled by solvent

Question 14

What happens to water in the light dependent stage of photosynthesis?

Answer 14

It is split (by light) to produce H+ ions, 1/2 O2 molecule and electrons

Question 15

Where do the electrons from water go in the light dependent stage?

Answer 15

replace the electrons lost from PS2

Question 16

Where do the electrons from PS2 go in the light dependent stage?

Answer 16

Down an electron transport chain (to produce ATP) and then replace the electrons lost from PS1.

Question 17

Where do the electrons from PS1 go in the light dependent stage?

Answer 17

To NADP reductase to produce NADPH

Question 18

What is cyclic photophosphorylation?

Answer 18

Electrons are excited and produce ATP in PS1 only. It does not go onto reduce NADP

Question 19

What is photophosphorylation?

Answer 19

The phosphorylation of ADP to produce ATP using light

Question 20

What is carbon fixation?

Answer 20

Changing CO2 to an organic molecule during photosynthesis.

Question 21

What does RuBP join with in the Calvin cycle? What does it form?

Answer 21

CO2 (with RuBisCo)

It forms two Glycerate-3-phosphate molecules

Question 22

What happens to 2x GP in the Calvin cycle?

Answer 22

It reduced using NADPH & ATP to form triose phosphate

Question 23

What happens to 2 x TP in the Calvin cycle?

Answer 23

One molecule is used to create proteins, glucose and lipids.

One molecule remains in the cycle and converts to RuBP

Question 24

What is the name for GP?

Answer 24

Glycerate 3 phosphate

Question 25

What is the name for TP?

Answer 25

Triose phosphate

Question 26

What are the limiting factors of photosynthesis?

Answer 26

Carbon dioxide, light intensity and temperature.

Question 27

How does temperature affect the calvin cycle?

Answer 27

denatures the enzymes and stops the cycle

Question 28

Why does reduced CO2 stop the Calvin cycle?

Answer 28

CO2 is not added to RuBP and GP molecules cannot be formed

Question 29

What are the products of the light dependent cycle needed for the Calvin cycle?

Answer 29

NADPH & ATP