Photosynthesis

Question 1

what are the two stages of photosynthesis

Answer 1

Light dependent and light independent reactions

Question 2

what is the rate of photosynthesis determined by

Answer 2

carbon dioxide concentration, light intensity and temperature

Question 3

give two ways chloroplasts are adapted for photosynthesis

Answer 3

1. Contains stacks of thylakoid membranes called grana which provides a large surface area for the attachment of chlorophyll, electrons and enzymes
2. contain DNA and ribosomes allowing them to synthesise proteins needed in the light dependent reaction

Question 4

which photosystem is used in the LDR

Answer 4

PSII(2)

Question 5

what is photoionasation

Answer 5

when electrons hit chlorophyll molecules and leave due to being excited which ionises the chlorophyll

Question 6

how many photons of light is required to split one molecule of water

Answer 6

4

Question 7

what are the products of photolysis

Answer 7

1 molecule of oxygen, 4 protons and 4 electrons

Question 8

what happens to the products of photolysis

Answer 8

1. oxygen is diffused out
2. electrons replaces the ones lost in chlorophyll
3. protons travel to stroma which later creates proton gradient

Question 9

what happens to the excited electron in the LDR

Answer 9

1. moves down a series of protein complexes and then at one protein complex the energy is used to pump protons from the stroma to the thylakoid space
2. electron moves towards PS1 , here more photons of light are absorbed making it move up at a higher energy level

Question 10

what is produced when the electron combines with a proton and what is it used for

Answer 10

hydrogen atom, used to reduce NADP and produce reduced NADP

Question 11

what is the last stage of the LDR

Answer 11

1. proton gradient forms, high concentration in thylakoid space, low concentration in stroma
2. protons move across membrane by diffusions through stalked particle
3. movement of protons drives process of photophosphorylation
4. ATP synthase phosphorylates ATP from ADP and Pi

Question 12

what are the four stages of the LIR?

Answer 12

1. Carbon dioxide fixation
2. Reduction phase
3. Regeneration of RuBP
4. Organic molecule production

Question 13

what happens in carbon dioxide fixation

Answer 13

Carbon dioxide that is diffused through the stroma is fixed with RuBP in a process called carboxylation -rubisco is needed. 6 carbon sugar is produced but then becomes 2 molecules of glycerate-3-phosphate (GP)

Question 14

what happens in the reduction phase

Answer 14

NADP reduces GP with energy from ATP. Forms 2 molecules of triose phosphate (TP)

Question 15

what happens in the regeneration of RuBP

Answer 15

5 molecules of TP are used to regenerate 3 molecules of RuBP

Question 15

what happens in organic molecule production

Answer 15

2 molecules of TP can combine to form hexose sugar fructose 1,6 bisphosphate where it forms glucose after

Question 16

how many turns of the Calvin cycle are required in order to produce 1 molecule of glucose per molecule of CO2

Answer 16

6