2. photosynthesis

Question 1

where does photosynthesis take place

Answer 1

in the chloroplasts of plant cells

Question 2

where does photosynthesis take place

Answer 2

in the chloroplasts of plant cells

Question 3

chloroplasts are

Answer 3

flattened organelles surrounded by a double membrane

Question 4

thylakoids (fluid-filled sacs) are

Answer 4

stacked up in the chloroplast into structures called grana (singular=granum)

Question 5

grana are linked together by

Answer 5

bits of thykaloid membrane called lamellae (singular=lamella)

Question 6

e.g. of photosynthetic pigments in chlorplasts

Answer 6

Chlorophyll A
chlorophyll B
carotene

Question 7

photosynthetic pigments are

Answer 7

coloured substances that absorb light energy needed for photosynthesis

Question 8

photosynthetic pigments are found

Answer 8

in thykloid membrane

attached to proteins

Question 9

photosynthetic pigment attached to protein is called a

Answer 9

photosystem

Question 10

contained within the membrane of the chloroplast and surrounding the thykloids is a

Answer 10

gel-like substance called the stroma

Question 11

what does the stroma contain

Answer 11

enzymes, sugars and organic acids

Question 12

carbohydrates produced by photosynthesis are not used straight away. they are

Answer 12

stored as starch grains in the stroma

Question 13

non-cyclic photophosphorylation

1. Light energy excites the electrons in the chlorophyll

Answer 13

1. light energy is absorbed by photosystem
2. excites electrons in chlorophyll
3. electrons move to higher energy level (they have more energy)
4. released from chlorophyll and move down electron transport chain

Question 14

non-cyclic photophosphorylation

2. photolysis of water produces protons (H+ ions) , electrons and O2

Answer 14

1. as excited electrons from chlorophyll leave Photosystem and move down electron transport chain must be replaced
2. light energy splits water into protons (H+ ions), electrons and O2 (photolysis)
3. the reaction is H2O -> 2H+ + 1/2O2

Question 15

non- cyclic photophosphorylation

3. energy from the excited electrons make ATP

Answer 15

1. excited electrons loose energy as they move down the electron transport chain
2. energy is used to transport protons into the thylakoid. thylakoid has higher concentration of protons in stroma. = proton gradient across thylakoid membrane
3. protons move down concentration gradient into stroma via enzyme ATP synthase (in thylakoid membrane) energy from movement combines ADP and inorganic phosphate to from ATP

Question 16

non-cyclic photophosphorylation

4. and generated reduced NADP

Answer 16

1. electrons are transferred to NADP along with a proton (H+ ion) from the stroma to form reduced NADP

Question 17

the light dependent reaction

some of the energy from released electrons is used

Answer 17

1. to add a phosphate group to ADP forming ATP (which transfers energy)
2. to reduce NADP to form reduced NADP (which transfers hydrogen to the light-independent reaction)

Question 18

the light dependent reaction

during the process, H2O is

Answer 18

oxidised to O2

Question 19

the light independent reaction

is also called the

Answer 19

Calvin cycle

Question 20

the light independent reaction

it doesn’t use

Answer 20

light energy directly

but it relys on the products of the light dependent reaction

Question 21

the light independent reaction

it takes place in the

Answer 21

stroma of the chloroplast

Question 22

the light independent reaction

what happens in the stroma of the chloroplast

Answer 22

ATP and reduced NADP from light dependent reaction supply energy and hydrogen to make simple sugars from CO2

Question 23

phostosystems in the thylakoid membranes are linked by

Answer 23

electron carriers

Question 24

electron carriers are

Answer 24

proteins that transfer electrons

Question 25

photosystems and electron carriers form an

Answer 25

electron transport chain (a chain of proteins through which excited electrons flow)

Question 26

Chemiosmotic theory/ Chemiosmosis

Answer 26

process of eletrons flowing down the electron transport chain and creating a proton gradient across the membrane to drive ATP synthesis

Question 27

non-cyclic photo phosphorylation produces

Answer 27

ATP, reduced NADP and O2

Question 28

cyclic photophosphorylation only produces

Answer 28

a small amount of ATP (no NADP or O2)

Question 29

cyclic photophosphorylation is called cyclic because

Answer 29

electrons from chlorophyll molecule arent passed onto NADP but are passed back to photosystem via electron carriers
(electrons are recycled and can repeatedly flow through Photosystem)