Chapter 10

Question 1

what is photosynthesis and its purpose

Answer 1

converts solar energy into chemical energy

Question 2

photsynthesis equation

Answer 2

CO2 + H2O + light energy —> (CH2O)n + O2

Question 3

autotrophs

Answer 3

• don’t eat anything derived from other organisms
• producers
• produce organic molecules from CO2

Question 4

heterotrophs

Answer 4

• obtain organic material from other organisms
• consumers of biosphere
• depend on photoautotrophs

Question 5

what type of reaction is photosynthesis

Answer 5

redox
- uses energy to build carbs

Question 6

what are the 2 steps of photosynthesis

Answer 6

1. light dependent reactions
2. Calvin cycle (light independent reactions)

Question 7

light dependent reactions

Answer 7

• produce O2 from H2O
• water is split to form O2
• ATP is produced

Question 8

what happens to electrons in the light dependent reactions

Answer 8

• get excited by light energy
• high energy electrons are transferred to electron carrier NADP+ to form NADPH

Question 9

what does the Calvin cycle use to reduce CO2

Answer 9

electrons and ATP

Question 10

what does the Calvin cycle produce

Answer 10

sugar from CO2

Question 11

where does photosynthesis take place

Answer 11

chloroplasts

Question 12

how many membranes do chloroplasts have

Answer 12

2

Question 13

thylakoids

Answer 13

• 1 big membrane folded on itself
• form grana stacks
• contain large quantities of pigment

Question 14

lumen

Answer 14

space inside thylakoid

Question 15

stroma

Answer 15

• space surrounding thylakoids

Question 16

what is the most common pigment in thylakoids

Answer 16

chlorophyll
- reflects green light

Question 17

accessory pigments

Answer 17

absorb and reflect other colors

Question 18

what type of light do plants primarily use

Answer 18

red and blue light
- red light= 700 wavelength
- blue light= around 380 wavelength

Question 19

pigments

Answer 19

• different pigments absorb different wavelengths
• wavelengths are reflected or transmitted

Question 20

chlorophylls

Answer 20

• absorb= red and blue light
• reflect= green light
  1. chlorophyll a
  2. chlorophyll b

Question 21

carotenoids

Answer 21

• absorb= blue and green light
• reflect= yellow, orange, and red light
• absorb excessive light that damages chlorophyll

Question 22

photon

Answer 22

particle of light

Question 23

difference between chlorophyll a and chlorophyll b

Answer 23

chlorophyll a is main photosynthetic pigment while chlorophyll b broaden the spectrum used

Question 24

what happens when pigment absorbs light

Answer 24

goes from ground state to an unstable excited state

Question 25

how does florescence hapopen

Answer 25

excited electrons fall back to ground state and photons are given off

Question 26

photosystem

Answer 26

chlorophyll molecules that work together - 2 major components 1. antenna complex 2. reaction center

Question 27

what are the two types of reaction centers

Answer 27

- photosystem 1 - photosystem 2 (happens first)

Question 28

what is the purpose of the photosystems

Answer 28

work together to produce enhancement effect and increase photosynthesis -abosrb light, transfer energy and electrons

Question 29

primary electron acceptor

Answer 29

accepts an excited electron from chlorophyll a - start button to photosynthesis

Question 30

what is the ultimate primary electron acceptor

Answer 30

reaction center complex

Question 31

photo phosphorylation

Answer 31

proteins building up to make ATP synthase move and turn to release energy

Question 32

photosystem 2

Answer 32

- water splitting complex to keep assembly line going - sunlight triggers excitement of electron

Question 33

photosystem 1

Answer 33

- lose some excitement when enter and then become more excited again because they tap into a different wavelength of light - low energy electrons are re-generated - reduce NADPH+ to NADPH

Question 34

why does photosystem 2 split water

Answer 34

to replace electrons lost

Question 35

what are the 3 phases of the Calvin cycle

Answer 35

1. fixation 2. reduction 3. regernation

Question 36

fixation

Answer 36

- CO2 reacts with ribulose (5 carbon compound) - results in 6 carbon molecule splitting into two 3PGA (3 carbon molecule) - converts, interacts, and fixes CO2 into sugar

Question 37

reduction

Answer 37

- 3GPA are phosphorylated by ATP and reduce NADPH - produce G3P - making sugars and then sugar is released

Question 38

regeneration

Answer 38

remaining G3P is used in reactions that use ATP

Question 39

G3P

Answer 39

- converted to whatever plant needs - sugar

Question 40

where does the calvin cycle occur

Answer 40

stroma of chloroplasts

Question 41

what does one turn of the calvin cycle fix

Answer 41

one molecule of CO2

Question 42

what does three turns of the calvin cycle do

Answer 42

- fixes 3 CO2 - produces 1 molecule of G3P - 3 regenerated RuBP

Question 43

how many times does the calvin cycle have to occur to produce 1 molecule of glucose

Answer 43

6 times

Question 44

rubisco

Answer 44

- very slow enzyme - slows rate of CO2 reduction - drawn to both O2 and CO2 so they compete - used in C3 plants

Question 45

what happens if there is no CO2

Answer 45

calvin cycle stops and a lethal backup of electrons occur

Question 46

photrespiration

Answer 46

undoes photosynthesis - serves as damage control - consume oxygen and releases fixed CO2

Question 47

stomata

Answer 47

pores that allow gas exchange

Question 48

what comes from light reactions

Answer 48

- ATP - electrons - O2

Question 49

what come into light reactions

Answer 49

- sunlight] - water - electrons

Question 50

what is the reaction center

Answer 50

start button for photosynthesis

Question 51

C3

Answer 51

- normal plant - mesophyll

Question 52

when does photosynthesis occur in C3 plants

Answer 52

all at the same time

Question 53

C4

Answer 53

- tropical plants - 4 carbon compound - bundle sheath - spacially divide steps of photosynthesis - carbon fixation and Calvin cycle occur in seperate cells

Question 54

CAM plants

Answer 54

- photosynthesis occurs at different times of day - dessert plants - form 4 carbon compound - open stomata at night and fix CO2 - release CO2 and run calvin cycle during the day when stomata are closed

Question 55

PEP carboxylase

Answer 55

- fix CO2 even when CO2 concentrations are low - fixes CO2 to a 3 carbon molecile in mesophyll cells - used in C4 plants

Question 56

where do the light dependent reactions happen

Answer 56

thylakoid in chloroplast

Question 57

where does the calvin cycle occur

Answer 57

stroma of chloroplast

Question 58

RuBP

Answer 58

- ribulose bisphosphate - 5 carbon compound