Oxidative phosphorylation

Question 1

Where are the hydrogen atoms collected by NAD and FAD delivered to?

Answer 1

• electron transport chains present in the membranes of the cristae of the mitochondria

Question 2

What happens to the hydrogen atoms

Answer 2

• dissociate to hydrogen ions and electrons

Question 3

What happens to the electrons?

Answer 3

• the high energy electrons are used in the synthesis of ATP by chemiosmosis
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Question 4

How is energy produced in the electron transport chain?

Answer 4

• energy is released during redox reactions as the electrons reduce and oxidise electrons carrier as they flow along the electron transport chain
• this energy is used to create a proton gradient leading to the diffusion of protons through ATP synthase resuliting in the synthesis of ATP

Question 5

What happens at the end of the electron transport chain?

Answer 5

• electrons combine with hydrogen ions and oxygen to form water
• oxygen is the final electron acceptor and the electron chain cannot operate unless oxygen is present
• respiration which involves the complete breakdown of glucose is therefore an aerobic process

Question 6

Why is it known as oxidative phosphorylation?

Answer 6

• phosphorylation of ADP to ATP is dependant on electrons moving along the electron transport chains
• this requires the presence of oxygen
• therefore it is known as oxidative phosphorylation

Question 7

What is substrate level phosphorylation?

Answer 7

• production of ATP involving the transfer of a phosphate group from a short-lived, highly reactive intermediate such as creatine phosphate
• this is different from oxidative phosphorylation which couples the flow of protons down the electrochemical gradient through ATP synthase to the phosphorylation of ADP to produce ATP