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Flashcards in Biochemistry Deck (56):
1

Glycogenesis

Converting glucose to glycogen

2

Glycogenolysis

Breakdown of glycogen to glucose

3

What is the purpose of liver glycogen?

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

4

What is the purpose of muscle glycogen?

Provide energy for glycolysis and the TCA cycle

5

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

Gluconeogenesis

6

Gluconeogenesis

Production of glucose from non-carbohydrate substrates

7

Name the 2 bonds in glycogen

a 1-4 glycosidic link
a 1-6 glucosidic link

8

Which glucosidic link makes branches

1-6

9

what is the primer in glycogen attached to?

Glycogenin

10

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

1. Glycolysis
2. Converted to glucose in the liver

11

Activated form of glucose

UDP-glucose

12

Activated form of phosphate

ATP

13

Activated form of acetate

Acetyl-CoA

14

Name the transporter which gets glucose into the bloodstream

GLUT2

15

Hexokinase

Converts glucose to glucose-6-phosphate

16

Phosphoglucomutase

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

17

UDP-glucose phosphorylase

Glucose-1-phosphate to UDP-glucose

18

Glycogen synthase

UDP glucose to glycogen

19

Glycogen phosphorylase

Glycogen to glucose-1-phosphate

20

Glucose-6-phosphatase

glucose-6-phosphate to glucose

21

Where does energy come from for gluconeogenesis?

Oxidation of fatty acids from adipose tissue

22

Where does gluconeogenesis occur?

Liver

23

What are the precursors of gluconeogenesis?

Lactate
Amino acids
Glycerol

24

What is synthesised to allow gluconeogenesis to continue?

Oxaloacetate

25

What does glucagon do?

Stimulate gluconeogenesis
Inhibit glycolysis

26

What does insulin do?

Inhibit gluconeogenesis
Stimulate glycolysis

27

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

Energy source
For essential fatty acids
Provides fat soluble vitamins

28

Name the three types of lipids

Simple lipids
Compound lipids
Steroids

29

What are triglycerides made of?

Glycerol + three fatty acids

30

3 main products of fat digestion

Glycerol
Fatty acids
Monoglycerides

31

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

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

32

How are resynthesises triglycerides carried?

Via chylomicrons

33

What are chylomicrons cleaved by and where?

Lipoprotein lipase in the muscle

34

Lipolysis

Breakdown of lipids

35

How is ACyl-CoA generated?

CoA + fatty acid

36

What transports Acyl to the matrix?

Acyl carnitine

37

Products of B-oxidation in the mitochondria?

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

38

Total ATP yield from oxidation of one stearic acid?

120 ATP

39

What are ketone bodies formed from?

Acetyl-CoA from B-oxidation

40

Why are ketones produced in uncontrolled diabetes?

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

41

Lipogenesis

Fatty acid synthesis

42

What happens to excess carbohydrate?

Converted to fatty acids and triglycerides in the liver

43

What transports acetyl groups into the cytoplasm?

Citrate (from TCA cycle)

44

Which enzyme activates Acetly-CoA into Malony-CoA?

Acetyl CoA carboxylase

45

When is fatty acid synthesis maximal?

When carbohydrates are abundant

46

What increases the action of Acetyl-CoA carboxylase?

Insulin and citrate

47

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

SLOWS action

48

What is required for the synthesis of triglycerides?

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

49

Are amino acids stored?

No - catabolised in liver mainly

50

What unwanted product does amino acid break down give?

Ammonium ions

51

How are they mainly excreted?

Via urine (produced in liver)

52

3 stages of urea synthesis

Transamination
De-amination
Urea cycle

53

Where does De-amination occur?

In the liver

54

What is the amino group converted to?

free ammonium ion

55

3 components of urea

Carbon dioxide
Free ammonium ion
Aspartate

56

What is the remaining carbon skeleton converted into?

TCA cycle intermediates