u3: light reactions and calvin cycle

Question 1

light reaction

Answer 1

• chlorphyll absorbs light, transfers electrons to NADP+, which is eventually reduced to make NADPH
• ATP also produced bc of photophosphorlylation (bc of photons)

Question 2

byproduct of light reactions

Answer 2

oxygen due to water splitting

Question 3

what happens when pigment absorbs a photon

Answer 3

• electron gets excited, from ground state (low energy) to excited state (high energy)

Question 4

how do electrons return to ground state?

Answer 4

by releasing thermal energy/fluorescense

Question 5

best pigment for chlorophyll

Answer 5

P680 and P700

Question 6

steps of light reactions

Answer 6

1. photoexcitation: photon excites electron from ground state to higher energy level
2. electron transport: produces NADPH
3. chemiosmosis: protons move through ATP synthase, energy used to make ADP + Pi into ATP

Question 7

what does calvin cycle do?

Answer 7

uses NADPH and ATP from light reactions to reduce CO2 into carbohydrates

Question 8

photosystem

Answer 8

clusters of chlorophyll, accessory pigments, and proteins

Question 9

photosystem I

Answer 9

P700

Question 10

photosystem II

Answer 10

P680

Question 11

antenna complex

Answer 11

chlorophyll, protein matrix, thylakoid membrane

Question 12

reaction centre

Answer 12

chlorophyll a and b

Question 13

primary electron acceptor

Answer 13

catches excited electron (redox)

Question 14

fluorescence

Answer 14

drop in energy, seen as light

Question 15

mitochondrial vs light reactions ETC

Answer 15

• mito: electron flow is down from high energy NADH to low energy H2O, spontaneous
• light reactions: foes from low energy H2O to high energy NADH, so needs light energy, not spontaneous (boosted twice via photon absorption)

Question 16

how many times does calvin cycle run to make one glucose molecule?

Answer 16

twice

Question 17

what is another word for the calvin cycle

Answer 17

light independent reaction

Question 18

steps in calvin cycle

Answer 18

1. CO2 goes in

Question 19

3 major stages of calvin cycle

Answer 19

1. carbon fixation
2. reduction
3. regeneration

Question 20

what is G3P

Answer 20

half glucose, half phosphate

Question 21

how many ATP used to make a glucose?

Answer 21

18

Question 22

calvin cycle: carbon fixation

Answer 22

RuBISco fixes RuBP to CO2, makes two 3-PGA molecules

Question 23

calvin cycle: reduction

Answer 23

1. 6 ATP in, 6 ADP out
2. 6 NADPH in, 6 NADP+ out
3. two G3P molecules join to make glucose

Question 24

calvin cycle: regeneration

Answer 24

1. 5 G3P molecules merge with 3 ATP, 3 ADP leave
2. 3 RuBP and 3 ADP outputted

Question 25

parts of a chloroplast

Answer 25

- outer membrane - inner membrane - intermembrane space - stroma - thylakoids/granum