Biochemistry

Question 1

Glycogenesis

Answer 1

Converting glucose to glycogen

Question 2

Glycogenolysis

Answer 2

Breakdown of glycogen to glucose

Question 3

What is the purpose of liver glycogen?

Answer 3

To be broken down between meals to provide glucose to blood and brain cells

Question 4

What is the purpose of muscle glycogen?

Answer 4

Provide energy for glycolysis and the TCA cycle

Question 5

What is the primary source of glucose through the night (i.e. when the body has no food stores?)

Answer 5

Gluconeogenesis

Question 6

Gluconeogenesis

Answer 6

Production of glucose from non-carbohydrate substrates

Question 7

Name the 2 bonds in glycogen

Answer 7

a 1-4 glycosidic link

a 1-6 glucosidic link

Question 8

Which glucosidic link makes branches

Answer 8

1-6

Question 9

what is the primer in glycogen attached to?

Answer 9

Glycogenin

Question 10

what are the two options of glucose-6-phosphate?

Answer 10

1. Glycolysis

2. Converted to glucose in the liver

Question 11

Activated form of glucose

Answer 11

UDP-glucose

Question 12

Activated form of phosphate

Answer 12

ATP

Question 13

Activated form of acetate

Answer 13

Acetyl-CoA

Question 14

Name the transporter which gets glucose into the bloodstream

Answer 14

GLUT2

Question 15

Hexokinase

Answer 15

Converts glucose to glucose-6-phosphate

Question 16

Phosphoglucomutase

Answer 16

Reversible reaction between Glucose-6-phosphate and glucose 1-phosphate

Question 17

UDP-glucose phosphorylase

Answer 17

Glucose-1-phosphate to UDP-glucose

Question 18

Glycogen synthase

Answer 18

UDP glucose to glycogen

Question 19

Glycogen phosphorylase

Answer 19

Glycogen to glucose-1-phosphate

Question 20

Glucose-6-phosphatase

Answer 20

glucose-6-phosphate to glucose

Question 21

Where does energy come from for gluconeogenesis?

Answer 21

Oxidation of fatty acids from adipose tissue

Question 22

Where does gluconeogenesis occur?

Answer 22

Liver

Question 23

What are the precursors of gluconeogenesis?

Answer 23

Lactate
Amino acids
Glycerol

Question 24

What is synthesised to allow gluconeogenesis to continue?

Answer 24

Oxaloacetate

Question 25

What does glucagon do?

Answer 25

Stimulate gluconeogenesis | Inhibit glycolysis

Question 26

What does insulin do?

Answer 26

Inhibit gluconeogenesis | Stimulate glycolysis

Question 27

Why is fat needed in the body (3 roles)?

Answer 27

Energy source For essential fatty acids Provides fat soluble vitamins

Question 28

Name the three types of lipids

Answer 28

Simple lipids Compound lipids Steroids

Question 29

What are triglycerides made of?

Answer 29

Glycerol + three fatty acids

Question 30

3 main products of fat digestion

Answer 30

Glycerol Fatty acids Monoglycerides

Question 31

What happens to fatty acids in the mucosa of the intestine (both short and long)?

Answer 31

Short - absorbed into blood stream | Long - resynthesises (along with monoglycerides) back to triglycerides

Question 32

How are resynthesises triglycerides carried?

Answer 32

Via chylomicrons

Question 33

What are chylomicrons cleaved by and where?

Answer 33

Lipoprotein lipase in the muscle

Question 34

Lipolysis

Answer 34

Breakdown of lipids

Question 35

How is ACyl-CoA generated?

Answer 35

CoA + fatty acid

Question 36

What transports Acyl to the matrix?

Answer 36

Acyl carnitine

Question 37

Products of B-oxidation in the mitochondria?

Answer 37

1 Acetyl-CoA 1 fatty Acyl-CoA 1 FADH2 1 NADH + H+

Question 38

Total ATP yield from oxidation of one stearic acid?

Answer 38

120 ATP

Question 39

What are ketone bodies formed from?

Answer 39

Acetyl-CoA from B-oxidation

Question 40

Why are ketones produced in uncontrolled diabetes?

Answer 40

There is no oxaloaceteate (being used up in gluconeogenesis) so Acetyl-CoA can't enter the TCA cycle to be made into energy

Question 41

Lipogenesis

Answer 41

Fatty acid synthesis

Question 42

What happens to excess carbohydrate?

Answer 42

Converted to fatty acids and triglycerides in the liver

Question 43

What transports acetyl groups into the cytoplasm?

Answer 43

Citrate (from TCA cycle)

Question 44

Which enzyme activates Acetly-CoA into Malony-CoA?

Answer 44

Acetyl CoA carboxylase

Question 45

When is fatty acid synthesis maximal?

Answer 45

When carbohydrates are abundant

Question 46

What increases the action of Acetyl-CoA carboxylase?

Answer 46

Insulin and citrate

Question 47

What does glucagon do to the action of Acetly-CoA carboxylase?

Answer 47

SLOWS action

Question 48

What is required for the synthesis of triglycerides?

Answer 48

Glycerol-3-phosphate from glycerol (liver) and glucose (fat)

Question 49

Are amino acids stored?

Answer 49

No - catabolised in liver mainly

Question 50

What unwanted product does amino acid break down give?

Answer 50

Ammonium ions

Question 51

How are they mainly excreted?

Answer 51

Via urine (produced in liver)

Question 52

3 stages of urea synthesis

Answer 52

Transamination De-amination Urea cycle

Question 53

Where does De-amination occur?

Answer 53

In the liver

Question 54

What is the amino group converted to?

Answer 54

free ammonium ion

Question 55

3 components of urea

Answer 55

Carbon dioxide Free ammonium ion Aspartate

Question 56

What is the remaining carbon skeleton converted into?

Answer 56

TCA cycle intermediates