Photosynthesis Chapter 8

Question 1

photosynthesis is a ___ reaction

Answer 1

redox

Question 2

energy for carb building comes from the

Answer 2

sun

Question 3

ultimate electron donor is

Answer 3

water

Question 4

oxygen is formed as

Answer 4

a by-product

Question 5

what is the equation for photosynthesis?

Answer 5

6CO2 + 6H2O–> C6H12O6 + O2

Question 6

how is ATP and NADPH made?

Answer 6

movement of electrons through photosynthetic ETC

Question 7

photosynthesis takes place in which organelle?

Answer 7

chloroplasts

Question 8

the PETC is located in

Answer 8

the thylakoid membrane

Question 9

thylakod membranes are grouped into sacs called

Answer 9

grana

Question 10

carbohydrate synthesis takes place in the

Answer 10

stroma

Question 11

cellular respiration is one of several features that __ organisms share with ___

Answer 11

heterotrophic; photosynthetic

Question 12

where does the calvin cycle take place?

Answer 12

in the stroma

Question 13

the incorporation of CO2 is catalyzed by

Answer 13

the enzyme rubisco

Question 14

3 major steps of calvin cycle

Answer 14

carboxylation (co2 added to 5 carbon molecule)
reduction (e’s transferred to compounds formed in step 1)
regeneration (of the 5 carbon molecule needed for carboxylation)

Question 15

first step of calvin cycle?

Answer 15

CO2 added to RuBP which gets catalyzed by rubisco

-RuBP & CO2 rubisco’s active site makes 6 carbon compound that breaks into two 3 carbon molecules

Question 16

what is the reducing agent of the calvin cycle?

Answer 16

NADPH

Question 17

what exactly does NADPH do?

Answer 17

reduces compounds made by rubisco by transferring electrons to allow carbs to be made from CO2

Question 18

the regeneration of RuBP requires

Answer 18

ATP

Question 19

how much of NADPH and ATP needed to regenerate RuBP for reach CO2 molecule?

Answer 19

2 NADPH for every 3 ATP

Question 20

carbs are stored in the form of

Answer 20

starch

Question 21

starch made during the day is later used

Answer 21

at night when the plant can’t photosynthesize

Question 22

why is chlorophyll so good at absorbing light?

Answer 22

large number of alternating single & dbl bonds in the head

Question 23

carotenoids

Answer 23

allow photosynthesis cells to absorb broader range of visible light

Question 24

energy is transferred between ___ molecules until it finally reaches

Answer 24

chlorophyll; reaction center

Question 25

___ is where light energy is converted to chemical energy

Answer 25

reaction center

Question 26

the electron transfer from reaction center to __ creates a ___ that leads to the formation of

Answer 26

molecules; redox reaction chain; NADPH

Question 27

the photosynthetic ETC connects two ___

Answer 27

photosystems

Question 28

photosystem II is used to __, photosystem I is used to ___

Answer 28

pull electrons from H2O; allow electron transfer to NADP+

Question 29

photosystem II isn’t strong enough to form ___, photosystem I isn’t strong enough to

Answer 29

NADPH; split water

Question 30

electrons are passed from ___ to ___ to create NADPH

Answer 30

photosystem I; ferredoxin

Question 31

the accumulation of ___ in the ____ drives the synthesis of ATP

Answer 31

protons; thylakoid lumen

Question 32

how do protons accumulate in the thylakoid lumen?

Answer 32

2 features of PETC:

• oxidation of water releases protons & oxygen into lumen
• cytochrome-b6f complex and plastoquinone function as a proton pump

Question 33

which 2 features does the proton pump involve?

Answer 33

• transport of 2 electrons and 2 protons, by diffusion of plastoquinone, from stroma side of PS II to the lumen side of the cytochrome b6f complex
• transfer of electrons w/n the cytochrome b6f complex toa s different mol of plastoquinone (gets more p’s from stroma and dumps into lumen)

Question 34

why is cyclic electron transport needed?

Answer 34

not enough ATP is produced by PETC so an additional pathway is needed

Question 35

what is cyclic electron transport?

Answer 35

e’s from PSI are redirected from ferredoxin back into the ETC by plastoquinone

Question 36

what are the 2 major challenges of photosynthesis?

Answer 36

• if greater light energy absorbed than the c. cycle uses, excess energy harms the cell
• rubisco can catalyze additional co2 or o2 adding o2 instead of co2 can greatly reduce amount of carbs produced

Question 37

how do reactive oxygen species come about? what does the cell do to combat this?

Answer 37

when there’s a lack of NADP+

• release chemicals to detoxify
• xanthophylls slow formation of them by reducing excess lt. energy

Question 38

cold temperatures cause

Answer 38

the c. cycle to run slowly

Question 39

photorespiration leads to

Answer 39

net loss of energy and carbon

Question 40

photorespiration drains ___ and results in ___

Answer 40

ATP/energy; oxidation & loss in form of CO2

Question 41

the better rubisco discriminates between CO2 and O2, the ___

Answer 41

slower it works

Question 42

the ability to use water as an electron donor in photosynthesis evolved in ___

Answer 42

cyanobacteria

Question 43

how did the 2 photosystems become incorporated?

Answer 43

duplication & divergence

Question 44

eukaryotic organisms believed to have gained photosynthesis by __

Answer 44

endosymbiosis

Question 45

evolution of photosynthesis

Answer 45

UV light was around, so there could have been UV-absorbing compounds to shield cells and then mutations over time to harness this power

Question 46

light dependent reactions take place in the

Answer 46

thylakoid membrane

Question 47

___ goes into the light dependent reactions and ___ come outs

Answer 47

photons, water; ATP, NADPH, CO2