lecture 27 - exracting energy from food

Question 1

What is the major energy intermediate of the cell?

Answer 1

ATP - adenosine triphosphate

Question 2

What are the high energy bonds found in ATP?

Answer 2

Phosphoanhydride bonds

Question 3

Why is ATP hydrolysis energetically favourable?

Answer 3

Has a Gibbs freee energy (delta G) value of -30kJ/mol

Question 4

Is ATP hydrolysis or synthesis energetically favourable?

Answer 4

Hydrolysis - releases energy when phosphate group is cleaved.

Question 5

What reaction is coupled to the hexokinase reaction in glycolysis to make it energetically favourable?

Answer 5

ATP hydrolysis

Question 6

What are the 2 key energy conversion reaction types in the pathways for processing food molecules for ATP synthesis?

Answer 6

Reactions converting between ATP and ADP, redox reactions where fuel molecules get oxidised.

Question 7

What molecule is referred to as a reducing equivalent?

Answer 7

Hydrogen (proton + electron)

Question 8

What is the role of hydrogen as a reducing equivelant?

Answer 8

Biological redox reactions often involve the transfer of hydrogen atoms, which include an electron (and a proton)

Question 9

What enzymes catalyse reactions involving hydrogen as a reducing equivelant?

Answer 9

dehydrogenases

Question 10

What is the name for a 16 carbon lipid?

Answer 10

Palmitate

Question 11

What type of reaction releases energy from fuel molecules?

Answer 11

Oxidation reaction

Question 12

What is stepwise oxidation?

Answer 12

Oxidation reaction that happens in several steps so that the energy releases can be captured efficiently for ATP production, rather than being released rapidly as heat.

Question 13

What molecules provide the oxidising power in redox reactions in the harvesting of energy from fuel molecules?

Answer 13

The coenzymes NAD and FAD

Question 14

What are the key features of the coenzymes NAD and FAD?

Answer 14

Low concentration in cells, act as carriers, exist in two forms

Question 15

What is NAD derived from?

Answer 15

Niacin (vitamin B3)

Question 16

What does NAD accept in metabolic pathways?

Answer 16

A hydrogen and an electron = H+ and 2e-

Question 17

IS NAD+ reduced or oxidised to NADH?

Answer 17

Reduced

Question 18

How is NAD+ reduced?

Answer 18

Undergoes a 2-electron reduction by accepting 2 reducing equivalents to gain 2 electrons, and also forms H+ in the process.

Question 19

What is the oxidised form of NAD?

Answer 19

NAD+

Question 20

What is the reduced form of NAD?

Answer 20

NADH

Question 21

What vitamin is FAD derived from?

Answer 21

Riboflavin (vitamin B2)

Question 22

What proteins are flavin coenzymes (e.g. FAD) tightly bound to and interact with?

Answer 22

Flavoproteins

Question 23

What reduction reaction does FAD undergo?

Answer 23

A 2 electron reduction - accepts 2 reducing equivalent - 2H+ and 2e-

Question 24

What is the reduced form of FAD?

Answer 24

FADH2

Question 25

What is the oxidised form of FAD?

Answer 25

FAD

Question 26

What vitamin is Coenzyme A (CoA) derived from?

Answer 26

Pantothenic Acid (Vitamin B5)

Question 27

Does CoA undergo redox reactions?

Answer 27

No - is not oxidised or reduced

Question 28

What does CoA carry?

Answer 28

Acyl groups - carbon chains

Question 29

What is the molecular formula for free Coenzyme A?

Answer 29

CoASH

Question 30

What is the molecular formula for CoA with an acyl group attached?

Answer 30

Acyl-CoA = AcCoA

Question 31

What are the 2 forms of Coenzyme A?

Answer 31

Free CoA (CoASH), CoA with acyl group attached (AcCoA)

Question 32

What type of molecule is free CoA - CoASH?

Answer 32

Thiol

Question 33

What does CoA react with to form Acyl-CoA?

Answer 33

H+ and an acyl group

Question 34

What type of molecule is Acyl-CoA?

Answer 34

Thioester

Question 35

What is the byproduct of the formation of Acyl-CoA?

Answer 35

H2O