lecture 27 - extracting energy from fuel molecules

Question 1

why is energy released from ATP

Answer 1

because it has phosphanhydride bonds = high energy, so when they are broken energy is released

Question 2

is ATP hydrolysis energetically favourable

Answer 2

yes

Question 3

is ATP synthesis energetically favourable

Answer 3

n, energetically unfavourable

Question 4

what are the two reactions types for processing food molecules for ATP synthesis

Answer 4

1. those involving ADP and ATP
2. redox reactions = fuel molecules get oxidised

Question 5

when is something oxidised

Answer 5

when it loses electrons

Question 6

when is something reduced

Answer 6

when it gains electrons

Question 7

what do biological redox reaction often involve and what are the enzymes that often catalyse these reactions called

Answer 7

often involve the transfer of hydrogen atoms (includes an e-)

• dehydrogenases = movement of a hydrogen

Question 8

what is the co enzyme NAD

Answer 8

• accepts a hydrogen and an electron in metabolic pathways (glycolysis, fatty acid oxidation, citric acid cycle)

Question 9

what reaction does NAD undergo and what are the two forms it can exist in

Answer 9

undergoes a two electron reduction (accepts two reducing equivalents)

NAD+ = oxidised form

NADH = reduced form

Question 10

what is the co enzyme FAD

Answer 10

• accepts two hydrogens in pathways (fatty acid oxidation, citric acid cycle)

Question 11

what reaction does FAD undergo and what are the two forms that it can exist in

Answer 11

undergoes a two electron reduction (accepts two reducing equivalents)

FAD = oxidised form

FADH2 = reduced form

Question 12

What is Coenzyme A (CoA)

Answer 12

• not a carrier of electrons ( not reduced / oxidised )
• carriers acyl groups

Question 13

what are the two forms of Coenzyme A

Answer 13

• free coenzyme A = CoASH
• acyl group attached = Acyl-CoA