Photosynthesis

Question 1

Photosynthesis

Answer 1

Energy and carbons made into carbohydrates
CO2 made to carbohydrates
sunlight is energy

Question 2

Calvin cycle

Answer 2

like citric acid cycle, but product is carb molecules instead of broken down one

Question 3

Photosynth

Answer 3

Co2+ Water= 6 carbon compound

Question 4

Where is oxidation

Answer 4

Deep in chloroplast

oxidizing water, it donates e-s

Question 5

chloroplasts

Answer 5

capture light energy and make it carbon organic molec

antithesis of mitochondria (which breaks down)

Question 6

Reduction is located…

Answer 6

Calvin cycle

Question 7

energy comes in forms of

Answer 7

ATP and NADPH (reduced form) (oxidized form is NADP+

Question 8

Chloroplast construction

Answer 8

3 membranes:
Outer membrane
inner membrane:
thykaloid membrane: photosystems here

Question 9

Chloroplast evolution

Answer 9

Chloroplast: was free living cyanobacteria with 2 membranes. Through endocytosis it was consumed by another cell. Inner membrane was its old outer membreane

Question 10

Thykaloid Membrane

Answer 10

Stacked into grana:where photosynthetic reactions happen. Light harvesting
Lumen: inside of thalakoid membrane

Question 11

Stroma

Answer 11

inside SECOND MEMBRANE (NOT in thalakoid membrane)

Question 12

Calcin Cycle Carboxylation:

Answer 12

input is CO2
Carboxylation: Add 1 carbon(CO2) to existing 5 carbon compound (RUBP) to make 6 carbon compound
6 C compound broken to 2 3-Carbon Compounds
Starts with RuBp, need to remake it b/c this is a cycle

Question 13

Rubisco

Answer 13

binds to CO2 (can also bind to oxygen:efficiency problems)
to make C6 out of RUbP and 1 carbon
must abundant enzyme on earth (lots b/c not super efficient)

Question 14

Calcin Cycle Reduction

Answer 14

reduce to make triosphospate
end up with 2 of them
each requires NRG input (ATP)
require transfer of electron

Question 15

Calcin Cycle oxidation

Answer 15

NADPH oxidized to NADP+

Question 16

Citric Acid cylce

Answer 16

needs to be run several times to get 6 carbon compound, and then to get RUPb back

Question 17

Triosphosphate

Answer 17

For every 6synthesized, only one can be used b/c need to regernerate RUBP with other 5

Question 18

Reorganization

Answer 18

5 3 carbon moleculs, make 3 5 carbon molecs (RUBP)

Question 19

For every CO2 molec

Answer 19

need 3 ATP and 3 NADPH

Question 20

Starch grannules

Answer 20

excess made, accumulate in chloroplast

used when cant run photosynth in abscence of light

Question 21

Light reactions: pigments

Answer 21

absorb lights at different wavelengths (WE SEE REFLECTIVE LIGHTS)
absorbed wavelenghts excite

Question 22

carotenoids

Answer 22

accessory pigments

Question 23

CHlrophyll

Answer 23

reflects green wavelengtsh

Question 24

Chlorophyll light absorption

Answer 24

long hydrocarbon tails anchored in thylakoid membrane
NRG passed from 1 cholorophyll to another
excited chlorophyll, pass down molecules
electron finally passed to reaction center, it becomes really excited
onto photosytems
hen electron passed off, need electron donor to replace the electron. Comes from splitting of water!
NADP+ to NADPH
made hydrogens, oxygen, reduce NADP+ to NADPH
ETC connnects the 2 photosystems

Question 25

Water splitting

Answer 25

oxygen and hydrogen ions released, electron sent to photosystem II

Question 26

Photosystem II

Answer 26

splits water
electron passed here
retrieves electron from water molec and uses it untill excited again
IN lumen (in thylakoid membrane)
cannot reduce NADP+ (cant get electrons to high enough NRG state)
supplies electrons

Question 27

Photosystem I

Answer 27

reduces NADP+
also in lumen?
cannot oxidize water
raises electrons to high enough energy to reduce

Question 28

Z scheme

Answer 28

PSystem2 raises elctron to high energy state, pases to 2

PSystem1 raises electron to even higher state

Question 29

Pumps from stroma to lumen

Answer 29

build up H ions in lumen (using light NRG and splitting water) (against gradient)
So ATP synthase can make ATP while hydrogens flow along electrochemical gradient

Question 30

inside of stroma

Answer 30

VERY ACIDIC b/c of so much extra hydrogen

1000X more acidic inside stroma

Question 31

Photosynthesis problems

Answer 31

High light envrionments: calvin cycle overwhelmed
too much NADPH, stalling out in calvin cycle
If no NADP+ regenerated, damage to cell b/c oxygen things: very reactive and harmful
Solution:pass hydrogen back, then pass it acorss membrane to make electrochem gradient

Question 32

Photosynthetic efficiency in High light envrionments

Answer 32

let accessory pigments absorb too. They will dissiminate much of the energy as heat and flourecense, don’t really help with ATP production

Question 33

Photorespiration

Answer 33

Rubisco problem
lots of Oxygen (O2), it outcompetes CO2 from binding to rubisco, dont make 2 3-carbon compouds, requires more energy, damage to cell
Rubisco only has a slightly higher affinity for CO2, so lots of O2 will override it
Rubisco speed problem: