8.3 Photosynthesis Flashcards Preview

Biology 8. Metabolism, Cell Respiration and Photosynthesis > 8.3 Photosynthesis > Flashcards

Flashcards in 8.3 Photosynthesis Deck (66)
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1

What is part of photosynthesis called that uses light directly?

light dependent

2

What is part of photosynthesis called that does not use light directly?

light independent

3

What are light independent reactions dependent on?

can work in dark but only shortly, need substances produced by light dependent reactions

4

what does the inner membrane of a chloroplast enclose?

third system of interconnected membranes called thyla koid membranes

5

What are thylakoid membranes?

third system of interconnected membranes enclosed by inner membrane of chloroplast

6

What is within thylakoid?

compartment called thylakoid space

7

What are the products of light dependent reactions

light energy converted into chemical energy in form of ATP and reduced NADP

8

What do ATP and NADP serve as for light independent reactions?

energy sources

9

What is a stroma

compartment which inner membrane of the chloroplast encloses; protein rich with enzymes to use for calvin cycle (light independent reactions)

10

What is the calvin cycle?

anabolic pathway for light independent reactions that require endergonic reactions so that ATP is hydrolised and reduced NADP is oxidized

11

What are photosystems?

chlorohyll and accessory pigments grouped together in large light harvesting arrays (contain chlorophyll)

12

Where are photosystems located?

in thylakoids, an arranment of membranes inside chloroplast

13

What do photosystems I and II have?

light harvesting arrays (with chlorophyll), reaction centres and many chlorophyll molecules that absorb light energy

14

What happens when chlorophylls in the reaction centre absorb energy?

when energy is absorbed from photon of light an electron within molecule gets excited. which makes chlorophyll photoactivated

15

How can a chlorophyll get photoactivated?

chlorophyll absorbs energy from photon of light, electron gets excited

16

What is a special property of chlorophylls in the reaction centre?

can donate excited electrons to electron acceptor

17

What is the electron acceptor of photosystem II called?

plastoquinon

18

What does plastoquinon do?

collects to excited electrons from photosystem II, then moved to another position in the membrane

19

Describe a property of plastoquinone

Hydrophobic; has no fixed position but remains within mmbrane

20

what does the absorption of two photons of light cause?

produces one reduced plastoquinone, where chlorophyll at reaction centre lost 2 electrons to plastoquinone

21

Can photosystem II repeat the process of producing a new plastoquinone?

Yes it can repeat the process and produce a second reduced plastoquinone

22

What does photo phosphorylation produce?

ATP using energy from light

23

Who carries out phosphorylation?

thylakoids

24

What does a thylakoid membrane include?

photosystem II; chain of electron carriers; photosystem I; ATP synthase

25

How are electrons carried from reaction centre of photosystem II to chain of electron carriers?

reduced plaetoquinone is needed

26

What happens once plastoquinone transfers its electrons?

electrons are passed from carrier to carrier in chain

27

What happens when electrons pass through the electron carrier chain?

energy is released from excited electrons from photosystem II which provides protein pumps to pump H+ across thylakoid membrane the lumen of the thylakoid; concentration gradient developed;

28

How is a concentration gradient created across the thylakoid membrane?

excited electrons from photosystem II is passed along electron carrier chain (cytochrome complex) which releases energy that actively transports H+ across membrane into lumen; photolysis also increases H+ concentration

29

How is ATP generated in thylakoids?

High concentration of H+ in thylakoid space is reduced by passing them through the enzyme ATP synthase; energy is released through the passive transport of H+ (down concentration gradient) synthesizes ATP from ADP +Pi

30

What is the process called when H+ passes through ATP synthase from high concentration to low, to convert ADP to ATP

chemiosis