Lecture 12 - Photosynthesis II

Question 1

What is photolysis?

Answer 1

light energy is used to split water into hydrogen and oxygen

Question 2

What is the equation for photolysis of water

Answer 2

2H2O –> 4H+ (+) 4e- (+) O2

Question 3

What is the light dependent stage?

Answer 3

Uses energy from light and hydrogen from photolysis to produce reduced NADP, ATP and Oxygen

Question 4

What is the light independent stage?

Answer 4

uses the reduced NADP and ATP to reduce (add hydrogen) to carbon dioxide to form carbohydrates

Question 5

What is a coenzyme?

Answer 5

organic non-protein that binds temp with substrate to an enzyme active site

Question 6

Name coenzymes during photosynthesis

Answer 6

NADP

Hydrogen carrier

Question 7

What happens in a photosystem?

Answer 7

photosynthetic pigments are embedded in the thylakoid membranes of the grana
in clusters called PHOTOSYSTEMS

Question 8

How does light energy reach the chlorophyl

Answer 8

1. Pigments funnel the light energy to the chlorophyll molecule at the reaction center, where it is absorbed

Question 9

what is the structure of chlorophyl?

Answer 9

1. porphyrin group with Mg at center

2. long hydrocarbon chain

Question 10

What happens during photoionistion?

Answer 10

1. In PS2: Single electron is released for each photon absorbed
2. PS1: Released electrons are accepted by Primary Acceptors located within thylakoid membranes

Question 11

What happens during Photophosphorylation?

Answer 11

1. Electron pass along electron carrier molecules of an electron transport chain embedded in thylkoid membranes.
2. lose energy which is used to synthesise atp
3. For the process to continue the lost electrons must be replaced
4. PS1 electrons are replaced by the electrons from PS2

Question 12

ATP is made during Chemiosmosis, What is chemiosmosis?

Answer 12

1. Energy released by electrons passing down electron transport chain
2. This used to pump hydrogen ions into thylakoid space
3. ATP is made when electrons pass along the electron transfer chain
4. Proton gradient is made

Question 13

How is NADP reduced?

Answer 13

1. Electrons from electron transport chain and hydrogens are released from ATP synthase which combine with NADP to give reduced NADP

Question 14

Where does the Light-independent reaction occur?

Answer 14

1. Stoma of chloroplast
2. Uses reduced NADP and ATP from previous stage to reduce co2 and from carbs
3. Occurs during calvin cycle