AP bio u4

Photosynthesis equation

6CO2 + 6H20 -> C6H12O6 + 6O2

In what does photosynthesis occur

green stems, unripened fruit, leaves of plants

Where does photosynthesis happen in the plant

palisade layer of leaf mesophyll

Where does gas exchange occur; what gasses

stomata (underside of leaf), w CO2 and O2

Stomata function

pores surrounded by guard cells that regulate volume by opening/closing via interaction w water

Guard cell function

2 cells that regulate the opening in which gases and water vapor pass

Chloroplast function

organelle responsible for photosynthesis

How many chloroplasts per mesophyll cell

30-40

Chloroplast structure

outer + inner membrane, stroma, thylakoid, granum, lumen

Chlorophyll

pigment molecule that absorbs E. are on photosystems (the circle things)

What are plant pigments

molecules that absorb or reflect light energy in specific wavelengths

Benefits of more pigments

more wavelengths of light that plant can absorb and use

chlorophyll wavelengths

absorb red/blue, reflect green

carotenoid wavelengths

absorb blue/green, reflecct orange/red

Where does the oxygen come from?

h2O

Where does the sugars come from?

CO2 and H2O

Where does light dependent reactions happen

photosystems in thylakoid membrane

Light dependent reactions inputs

24 ADP, 12 NADP+, 12 H2O, light

Light dependent reactions outputs

24 ATP, 12 NADPH, 6 O2

Excitation of chlorophyll

photon hits electron and excites it. when falling back into ground state, releases E as heat + photon which leads to a chain reaction. eventually E passed to reaction center chlorophyll

Reaction center chlorophyll

ionizes and gives electron to primary electron acceptor

Noncyclic electron flow

photon hits PSII and electron eventually accepted by primary electron acceptor. hole is replaced by water (H+ stay inside thylakoid/lumen). same things occurs in PSI but hole replaced by electron from PSI. after, electron passes down a transport chain that eventually reduces NADP+ to NADPH w the electron and H+ from stroma via NADP+ reductase.

ATP synthase in photosynthesis

H+ gradient established provides E, with thylakoid space/lumen having high H+ and stroma having low. makes 24 ATP

Water splits into

6 O2, 24 H+, 24 e-

PS680

reaction center chlorophyll of PSII

PS700

reaction center chlorophyll of PSI

Enzyme splits water in which PS

PSII

How many ATP and NADPH made in noncyclic

24 ATP, 12 NADPH

Cyclic electron flow

occurs in PSI w light, CO is low, making ATP. same electron reused.

Where does Calvin Cycle occur

stroma

Light independent reactions input

6 CO2, 18 ATP, 12 NADPH

Light independent reactions outputs

C6H12O2, 18 ADP, 12 NADP+, 6 H2O

Cycle begins/ends with what

RuBP

How many cycles to make a glucose

6

How many co2 fixed at a time

1

Carbon fixation equation

6CO2 + 6 RuBP -> 12 3PG

Carbon fixation process

rubisco combines Co2 w RuBP to create 2 3PG

Reduction equation

12 3PG + 12 NADPH + 12 ATP -> 12 G3P + 12 NADP+ + 12 ADP

Reduction process

2 G3P turned into glucose, the rest 10 continue cycle

RuBP regen equation

10 G3P + 6 ATP -> 6 RuBP

RuBP process

total 30 carbons on both sides

Amount of energy used (consumed) per glucose

18 ATP and 12 NADPH

How much ATP produced in dependent vs how much ATP used in independent

24 produced vs 18 used

Transpiration cohesion-tension theory

water moves up plant via xylem, molecules evaporating through leaf stomata pulls up water via cohesion + adhesion

Psi gradient from soil to air

greatest water potential in soil -> lowest in air

Root pressure

roots hairs inc SA, roots taking in minerals in the soil around it makes water follow in via osmosis (passive)

Transpirational pull

evaporation of water vapor from leaves pulls more water up due to cohesion + adhesion, due to water potential differences in xylem, leaf, air

Translocation process

sugar moves into phloem cells, water from neighboring xylem moves in via osmosis, extra volume generates pressure which pushes contents from source to sink, sugars sink back into cell and water diffuses back into xylem

Role of proton pump in translocation of sugars

acts as a cotransporter

Photoperiodism

plants response to seasonal changes in day lengths

Germination

plant seeds breaking dormacy

Red light vs far red light

red light is GO, increasing germination vs fr light inhibits germination, increases upward growth (to avoid shade, since sun is above)

Active vs inactive

Pfr is acitve vs Pr is inactive

Phytochrome

light absorbing pigments that respond to light and influence a plant's behavior. can be photo reversible

What does seed activity depend on?

last light signal they receive, so effects of r light or fr light are both reversible

Critical factor for flowering

night length, as it can be disrupted/reversed via r or fr light

Phototropism

growing towards light

Gravitropism

growing towards gravity

Thigmotropism

growing to whatever it touches