Light Reactions

chloroplasts are a —membraned organelle

double

site of glucose synthesis

stroma

site of light reactions

thylakoid membrane

In what part of the chloroplast do the light reactions occur?

thylakoid membrane

dark reactions (carbon fixation) occur in

stroma

light reactions result in oxidation of — to —

H2O, O2

light reactions result in reduction of — to —

NADP+, NADPH

light reactions result in the generation of an — for ATP synthesis

H+ gradient

absorption of light by photoreceptor molecules causes —

electrons to jump to a higher energy state

when excited electrons return to ground state they can release — or —

light, heat

in photosynthesis, electrons bounce between atoms rather than being released as — or —

light, heat

— is the primary light acceptor in green plants

chlorophyll

alternating C-C and C=C bonds create —, where electrons are not held tightly in a particular atom

resonance structures

primary chlorophyll in green plants

chlorophyll a

absorbs light at slightly different wavelengths

chlorophyll b

What characteristic of chlorophyll makes it a more effective photoreceptor relative to other pigments?

Ability to form numerous resonance structures

— absorbs blue and red very efficiently

chlorophyll

chlorophyll reflects — light

green

step one of resonance energy transfer

electron is excited and jumps to higher state

step two of resonance energy transfer

excited electron falls back to its lower energy state, releasing energy

step three of resonance energy transfer

electron in nearby molecule absorbs released energy and jumps to high-energy state

photoinduced charge seperation

electron moves to nearby molecule with lower excited state

photoinduced charge seperation causes the initial molecule to have a — and the acceptor molecule to have a — charge

positive, negative

resonance energy transfer is the —

transfer of energy

photoinduced charge seperation is the —

transfer of an electron

chlorophyll undergoes photoinduced charge seperation in the —

reaction center

photosystem II

light excited electron, transferring to photosystem I

photosystem I

excited to reducing power: NADPH

P680 is a specialized chlorophyll in the reaction center of —

photosystem II

P680* is a strong — agent

reducing

P680* is the — state

excited

P680+ is a strong — agent

oxidizing

P680 absorption peak is — nm

680

chlorophyll a absorption peak is — nm

670

cytochrome b6f links — to —

photosystem II, photosystem I

cytochrome b6f is analogous to — of the ETC

complex III

plastoquinol releases 2 H+ into the —

thylakoid lumen

two H+ are pumped from the — to the —

stroma, thylakoid lumen

P700 is a spealized chlorophyll in the reaction center of —

photosystem I

P700 absorption peak is — nm

700

chlorophyll a absorption peak is —nm

670

P700* is a strong — agent

reducing

P700+ is a strong — agent

oxidizing

ferredoxin-NADP+ reductase is used to generate —

NADPH

formation of NADPH occurs in the —

stroma

FAD is a —/coenzyme

prosthetic group

Which of the following increases the concentration of H+ in the thylakoid lumen?

Oxidation of H2O & Transfer of electrons from plastoquinol to plastocyanin

photosystem II events

oxidation of H2O to O2
generation of a H+ gradient

cytochrome b6f events

generation of a H+ gradient

photosystem I events

reduction of ferredoxin

ferredoxin-NADP+ reductase events

generation of NADPH

WOC contains manganese and calcium ions bound to — molecules

water

electrons from water are transferred to plastoquinol via —

photosystem II

which of the following 2 increases the concentration of H+ in the thylakoid lumen?

transfer of electrons from plastiquinol to plastocyanin

oxidation of H2O

oxidation of two H2O to one O2
how many photons of light absorbed

how many NADPH are produced

how many H+ pumped into thylakoid lumen

8, 2, 12

ATP synthesis in plants

Cf1-CF0 complex

similar to mitochondrial F1-F0 complex

12 subunits of c ring

H+ is pumped from thylakoid lumen into —

stroma

ATP is released into the —

stroma

gamma subunit contains a disulfide bond

mjust be reduced for ATP synthase to function

thioredoxin acts as a — agent

reducing

sunlight controls oxidation state of —

ferredoxin

ferredoxin controls the oxidation state of —

thioredoxin

cyclic photophosphorylation produces ATP but not —

NADPH

components of photosynthesis are highly organized

thylakoid membranes are organized into stacked and unstacked regions
photosystem II and cytochrome b6f are located mostly in stacked regions
photosystem I and ATP synthase are in unstacked regions