Photoionisation and photophosphorylation

Question 1

Light is absorbed by

Answer 1

pigments located in the thylakoid membrane

Question 2

photoionization meaning

Answer 2

Two electrons in the chlorophyll molecule are excited to a higher energy level and are emitted from the chlorophyll molecule

Question 3

Each excited electron is passed down a chain of…………. which is called

Answer 3

electron carriers known as an electron transport chain

Question 4

During this process chemiosmosis occurs:
The energy given by the electrons moving through the electron transport chain enables H­­+ ions (protons) to

Answer 4

pass from a low concentration in the stroma to a high concentration in the thylakoid lumen

Question 5

The creation of this proton gradient across the membrane later drives the

Answer 5

synthesis of ATP in photophosphorylation

Question 6

The thylakoid contains a water-splitting enzyme called the

Answer 6

oxygen-evolving complex

Question 7

what does the oxygen-evolving complex do

Answer 7

catalyses the breakdown (photolysis) of water by light:

Question 8

oxygen-evolving complex equation

Answer 8

H2O → 2H+ + 2e- + ½O2

Question 9

As the excited electrons pass down the electron transport chain, they are replaced by

Answer 9

electrons from the photolysis of water

Question 10

The excited electrons pass along an electron transport chain, alternatively …………… proteins as they are accepted then passed on

Answer 10

reducing and oxidising

Question 11

The excited electrons pass along an electron transport chain, alternatively reducing and oxidising proteins as they are accepted then passed on
These electrons combine with

Answer 11

hydrogen ions (produced by the photolysis of water and transported out of the thylakoid lumen by ATP synthase) and the carrier molecule NADP to give reduced NADP:
2H+ + 2e- + NADP → reduced NADP

Question 12

The excited electrons pass along an electron transport chain, alternatively reducing and oxidising proteins as they are accepted then passed on
These electrons combine with hydrogen ions (produced by the photolysis of water and transported out of the thylakoid lumen by ATP synthase) and the carrier molecule NADP to give reduced NADP:
2H+ + 2e- + NADP → reduced NADP

The reduced NADP (NADPH) then passes to the light-independent reactions to be used in the

Answer 12

synthesis of carbohydrates