Energy 1: Metabolism, ATP, Glycolysis

Question 1

What is metabolism?

Answer 1

The use of energy to:
Synthesise new molecules
Establish ion gradients
Perform mechanical work
Keep warm

Question 2

What are catabolic processes?

Answer 2

The breakdown of complex molecules to release energy

Question 3

What are anabolic processes?

Answer 3

Synthesis of new molecules from less complexes components

Question 4

When is ATP production mainly done?

Answer 4

When nutrients are oxidised

Question 5

By which processes is ATP broken down?

Answer 5

Biosynthesis, detoxification, contraction, ion transport, thermogenesis

Question 6

How much ATP is available from the hydrolysis of ATP?

Answer 6

65 Kj/Mol

Question 7

How much ATP do we use at rest?

Answer 7

40Kg/24 Hr

Question 8

How much ATP do we use during exercise?

Answer 8

0.5 Kg/min

Question 9

What’s the total body content of ATP?

Answer 9

100g

Question 10

What do the cofactors NAD and FAD do?

Answer 10

Activated carriers of electrons used for oxidation or reduction reactions?

Question 11

What does NAD stand for?

Answer 11

Nicotinamide adenine dinucleotide

Question 12

What does FAD stand for?

Answer 12

Flavin adenine dinucleotide

Question 13

What are the oxidised and reduced forms of NAD?

Answer 13

Oxidised= NAD+
Reduced= NADH+

Question 14

What are the oxidised and reduced forms of FAD?

Answer 14

Oxidised= FAD+
Reduced= FADH2

Question 15

What is glycolysis?

Answer 15

The splitting of a glucose (C6) molecule into two pyruvate (C3) molecules

Question 16

What are the two functions of the formation of glucose 6- phosphate?

Answer 16

• maintains the glucose gradient

- traps the glucose within the cell (which is largely irreversible)

Question 17

What are the reactants in glycolysis?

Answer 17

1 glucose
2 ATP
2NAD+
2 ADP
2Pi

Question 18

What are the products of glycolysis?

Answer 18

2 pyruvate
2 NADH
2 ATP

Question 19

How is there a net gain of 2 ATP and 2 NADH in glycolysis?

Answer 19

The second step happens twice ( as 2x C3 molecules)

Question 20

What regulates glycolysis?

Answer 20

• enzyme catalysing irreversible reactions that are potential sites for regulation
• enzyme regulation

Question 21

How can activity of enzymes be regulated?

Answer 21

• reversible binding of allosteric effectors
• covalent modification
• transcription

Question 22

What does hexokinase do?

Answer 22

Regulates glucose -> G6P

Question 23

What does phosphofructokinase do?

Answer 23

Fructose 6 phosphate ->Fructose 1,6 bisphosphate

Question 24

In which tissue does pyruvate kinase have more points for allosteric regulation?

Answer 24

Liver

Question 25

What tissues don’t have the pyruvate kinase allosteric regulation sites?

Answer 25

Heart, brain, and skeletal system

Question 26

What happens in tissues that don’t have the pyruvate kinase allosteric regulation sites?

Answer 26

They aren’t regulated at the level of pyruvate kinase?

Question 27

What does pyruvate kinase do?

Answer 27

Phosphoenol pyruvate-> pyruvate

Question 28

How is hexokinase regulated?

Answer 28

Inhibited by G6P so prevents too much glucose being fed down the glycolytic pathway

Question 29

How is phosphofructokinase regulated?

Answer 29

Inhibited by ATP, citrate and H+ | Positively regulated by AMP

Question 30

What is AMP a good indicator of?

Answer 30

The energetic state of the cell

Question 31

Why is phosphofructokinase inhibited by ATP?

Answer 31

No need for glycolysis if ATP is present within the cell

Question 32

Why is phosphofructokinase inhibited by citrate?

Answer 32

Leads onto the TCA cycle which produces ATP

Question 33

Why is phosphofructokinase inhibited by H+?

Answer 33

Prevents the skeletal muscle being damaged by the low pH of continued glycolysis

Question 34

What is pyruvate kinase inhibited by?

Answer 34

ATP

Question 35

When is AMP produced?

Answer 35

When there is significant amounts of ADP

Question 36

When is ADP elevated

Answer 36

When the consumption of ATP is high and synthesis of ATP is required

Question 37

What enzyme makes AMP?

Answer 37

Adenylate kinase

Question 38

What is the reaction that has ATP, ADP and AMP?

Answer 38

2ADP => ATP +AMP

Question 39

How does high ATP concs inhibit phosphofructokinase (PFK)?

Answer 39

Lowers the affinity for fructose 6 phosphate

Question 40

What does inhibition of PFK lead to?

Answer 40

Hexokinase as a reduction of PFK use leads to an increase of G6P and therefore an inhibition of hexokinase

Question 41

What is PFK inhibited by?

Answer 41

High ATP conc and citrate

Question 42

What is PFK stimulated by?

Answer 42

Indirectly by a F6P build up

Question 43

What is hexokinase inhibited by?

Answer 43

G6P

Question 44

What molecules mean that other molecules can join the glycolytic pathway?

Answer 44

Fructose (adipose)-> F6P Fructose (liver)->DMAP Fructose (liver)->GAP

Question 45

How can glycolysis be inhibited?

Answer 45

The amount of NAD in the cell

Question 46

How do muscles overcome the lack of NAD+?

Answer 46

Synthesis of lactic acid lactate from pyruvate

Question 47

What are the limitations of using lactic acid as a source of glucose?

Answer 47

Lactic acid is acidic so will lead to a reduction in pH which has an inhibiting effect on PFK

Question 48

What happens to the pyruvate in an aerobic state?

Answer 48

Converted to acetyl coenzyme A which then leads to the process of oxidative phosphorylation

Question 49

What happens to the vascular system when a tumour grows?

Answer 49

As size increases, the need for blood grows. Angiogenic factors are released which ultimately leads to the formation of a vascular network

Question 50

What is an angiogenic factor?

Answer 50

Stimulate the endothelial cells of a nearby vessel to proliferate and migrate

Question 51

Why are tumours kept in an anaerobic state?

Answer 51

The rate at which the tumour grows is faster than the vessels are able to deliver oxygen

Question 52

What stimulates the expression of many glycolytic enzymes?

Answer 52

Low oxygen

Question 53

What happens in hypoxia?

Answer 53

HIF1 activated which stimulates blood vessel growth and metabolic adaptation