Lecture 11 Flashcards Preview

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Flashcards in Lecture 11 Deck (15):
1

How is chlorophyll capable of absorbing photons?

The porphyrin ring possess a magnesium ion and an alternating single and double bonds. The system of double bond (resonance) is able to channel the energy absorbed.

2

Where does photosynthesis occurs?

In the photosystems present in the thylakoid membrane

3

What does photosystem contains?

chlorophyll-a, associated pigments and accessory proteins required to carry out photosynthesis

4

Photosystems are made of...

antenna complex and reaction centres

5

What is the role of the antenna complex?

capture and transfer the energy from light to the reaction centre

6

Where do the light dependent reactions occur?

In the thylakoid and the thylakoid membrane

7

What is the first step?

Primary photoevent: pigments are excited by a photon

8

What is the second step?

Charge separation: energy is transferred to the reaction centre, where an electron is transferred to an electron acceptor

9

What is the third step?

Electron transport: electron transport chain = create proton gradient and use to reduce the final electron acceptor NADPH

10

What is the complete reaction?

Photosystem 2 >> quinone >> plastoquinone >> b6-f complex >> plastocyanin >> photosystem 1 >> quinone >> ferredoxin (NADP >> NADPH)

11

What donates an electron to the quinone?

manganese ion

12

How many photons it requires to complete the oxidation of 2 molecules to produce molecular oxygen (2 electrons per water)

4

13

What is b6-f complex?

a proton pump and it uses the energy from the electrons to pump H+ into the thylakoid lumen

14

What is ferroredoxin?

it donates the electrons to NADP+ creating NADPH via the enzyme NADP reductase

15

Where is found NADP reductase?

In the stromal side of the thylakoid membrane