13 Chloroplasts- Cell Bio

4 distinct chloroplast compartments

envelope membranes

stroma inside

thylakoid membranes

lumen

Light-dependent reactions

in thylakoid membrane

light energy absorbed

water split

energy used to make ATP and NADPH (light to chemical)

Light-independent reactions

in stroma

carbon dioxide used

ATP and NADPH from the light reactions

major differences between photo and oxidative phosphorylation

Photophosphorylation produces O2

oxidative need O2

What anchors chlorophyll in the thylakoid membrane

hydrophobic tail

T or F: Thylakoids are membrane-bound structures within chloroplasts that contain chlorophyll and are organized into stacks called grana.

True

What are the two parts of photosystems?

The antenna= site of energy transfer

The reaction center= site of electron transfer

T or F: the reaction center converts light to chemical energy

True

In photosystem II, where are electrons transferred from and to?

Electrons are transferred to plastoquinone and then to the cytochrome b6-f complex that pumps H+ into the thylakoid space (used for ATP synthase)

What is split in PSII?

Oxygen is generated by a water splitting enzyme

Where is the photosystem II located?

in thylakoid membrane with antenna complex, reaction center, and water-splitting enzyme

Flow of electrons in photosystem I

received from plastocyanin through ETC, transferred to ferredoxin, which brings them to an enzyme that produces NADPH

Differences between PSI and PSII

In II electrons from split H2O, in I electrons from II

Products in II is proton gradient for ATP synthase, I produces NADPH

What do photosystems I and II power the production of?

ATP and NADPH

How is additional ATP generated when needed by the Calvin Cycle?

In PSI, instead of electrons going back to NADP+, electrons are cycled back to PSI producing ATP (no NADPH or oxygen).

What happens if PSII is blocked during photosynthesis?

chloroplast will perform cyclic photophosphorylation to generate small amount of ATP

What is cyclic photophosphorylation?

PSI generates a small amount of ATP by cycling electrons back into itself

How are electrons raised to a higher energy state in the photosystems?

in PSII, photons excite the electrons

Regarding light-harvesting complexes (antennas) in plant chloroplasts, which of the following is false?

They contain chlorophyll and other pigments

They are found in both photosystems

They can carry out charge separation

They do not contain special pair chlorophyll

They can carry out charge separation (only oxygen splitting enzyme can do that)

What are the three steps to the calvin cycle?

carboxylation

reduction

regeneration

Carboxylation

ribulose-1,5-bisphosphate to 3-phosphoglycerate

Reduction

ATP + NADPH= ADP+P1+NADP+

Regeneration

ATP to ADP

What is the net gain of carbon fixation?

1 molecule of glyceraldehyde 3-phosphate (G3P)

How many ATP and NADPH are consumed through the Calvin Cycle to produce one molecule of glucose?

18 ATP and 12 NADPH

What does the calvin cycle do?

reduce CO2 to produce a 3-carbon sugar

What is the relationship between the light reactions and the Calvin cycle?

The light reaction provide ATP and NADPH to the calvin cycle and the calvin cycle returns ADP, Pi, and NADP+ to the light reactions