Biology Midterm Review - Photosynthesis

Front 1

Background - what are plants?

Back 1

produce their own food, use energy from sun

Front 2

Where does photosynthesis occur?

Back 2

In choroplasts of mesophyll cells

Front 3

Very specific structure
Thylakoids
Grana
Stroma

Back 3

- site of light reactions
- stacks of thylakoids
- spaces btw thylakoids

Front 4

The two stages of photosynthesis

Back 4

Light reactions
Dark reactions

Front 5

Light reactions
Location
Input
Output

Back 5

thylakoids
- electrons and photons from water, photons from sun, NADP+, ADP + Pi
- ATP and NADP, release O2

Front 6

Dark reactions
Location
Input
Output

Back 6

stroma
- NADPH, ATP, CO2
- sugar, NADP, ADP + Pi

Front 7

Importance of pigments in light reactions:

Back 7

diff wavelengths absorbed (we can't see) and reflected (we can see) make different colors
also release electrons

Front 8

Absorption spectra:

Back 8

shows wavelengths that have been absorbed by chloroplasts

Front 9

Action spectra:

Back 9

Shows rate of photosynthesis at different wavelengths

Front 10

cholorphyll a vs. chlorophyll b

Back 10

a is directly involved, b is an accessory pigment, helping to catch light

Front 11

purpose of carotenoids

Back 11

photo-protection, which protects plants from damage from light, etc.

Front 12

two main parts to a photosystem:
Light harvesting
reaction center

Back 12

- contain pigments, bound to proteins and transfer photons to reaction center
- two cholophyll a molecules associated with specific proteins, primary e acceptor for electrons

Front 13

Two types of photosystems

Two electron transport chains

Back 13

PSI - 700 nm
PSII - 680 nm

between PSI and PSII (produces ATP)
between PSI and Fb (converts NADP to NADH)

Front 14

PSII - how does it start?

Back 14

- activate chlorophyll a electrons, taken by e acceptor
- go through first electron chain, when e is carried off to psI
- protons (H+) accumulate in thylakoid space, enhancing proton gradient, used to power ATP synthase and produce ATP

Front 15

PSI - how does it work?

Back 15

- e is activated and picked up by primary electron receptor
-2nd electron transport chain to ferredoxin (Fd)
-Enzyme NADP+ catalyzes transfer of electrons from Fd to NADP to produce NADPH (used in calvin cycle)

Front 16

Linear vs. Cyclic electron flow

Back 16

Linear - uses PSI and PSII to produce ATP and NADPH
Cyclic - uses only PSI and one electron transport chain, producing only ATP

Front 17

DARK REACTIONS
- name the three main phases of the calvin cycle

Back 17

1) carbon fixation
- (CO2 ENTERS)
- combines with RuBP
- reaction is catalyzed by rubisco

2) Reduction
- input of phosphate from ATP
- electrons from NADPH
- 1 3 C molecule leaves to start synthesis of glucose (from 3 CO2 molecules)

3) Regeneration of CO2 acceptor (RuBP)
i. 3 atps rearrange to form 3 RUBP, which allows cycle to begin again

Front 18

C3 plant photorespiration

Back 18

to protect against damage from excess light, no sugar production

Front 19

CAM plants and C4 plants photorespiration

Back 19

Crassulacean acid metabolism (CAM) plants store CO2
C4 plants have a prominent bundles sheath cells (Fig. 10.19)

Both produce sugars