Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GI > Metabolic Pathways > Flashcards

Metabolic Pathways Flashcards

1
Q

Glycogenesis

A

Glucose->glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Glycogenolysis

A

breakdown of glycogen to form glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Gluconeogenesis

A

de novo synthesis of glucose from metabolic precursors (lactate amino acids, glycerol)

Essentialy the reverse of glycolysis

ie synthesis of glucose within the body from precursor substrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Role of glycogen

A

main storage form of glucose in liver and muscle cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When is liver glycogen broken down?

A

Between meals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is liver glycogen released?

A

To maintain blood glucose levels for RBC and the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Role of muscle glycogen cells?

A

not for maintenance of blood glucose levels

provide energy via glycolysis and TCA during bursts of physical activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the primary source of glucose overnight when hepatic glycogen is depleted?

A

gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Structure of glycogen

A

polymer consisting of glucose molecules joined by alpha 1-4 glycosidic links

Branches introduced by alpha 1-6 glycosidic links

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Primer for adding glucose residue to a glycogen chain

A

glycogenin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What causes glycogenolysis to fluctuate?

A

It fluctuates depending on meal times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can UDP-glucose be thought of as?

A

An active intermediate of glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens to the phosphate ester linkage in a nucleotide sugar during hydrolysis?

A

It releases free energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Role of glycogen synthase

A

Rate limiting enzyme of glycogenesis

Makes glycogen from UDP-glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Glycogen breakdown summary

A

Glycogen-> glucose-1-phosphate-> glucose-6-phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Role of glycogen phosphorylase

A

Rate limiting enzyme for glycogenolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Enzyme involved in lysis of glucose-1-phosphate to form glucose-6-phosphate

A

Phosphoglucomutase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Precursor substrates involved in gluconeogenesis

A

Lactate, amino acids, glycerol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

synthesis of lactate

A

made by skeletal muscle under anaerobic condtions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are amino acids derived from?

A

muscle protein by proteolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is glycerol derived from?

A

triglycerides by lipolysis in adipose tissue

22
Q

Where is energy for gluconeogenesis from?

A

oxidation of fatty acids released from adipose tissue

23
Q

where does gluconeogenesis occur?

A

Mainly in the liver, but small amounts in the kidneys

24
Q

Gluconeogenesis proceeds via the synthesis of _____ in the _____

A

Oxaloacetate

Mitochondria

25
Q

Oxaloacetate

A

TCA cycle intermediate which is important for accepting acetyl groups from fat break down

26
Q

Cori cycle

A

Lactate produced in muscle

Blood transfers lactate to liver

Liver converts lactate back to glucose

Glucose released to bloodstream

27
Q

Why is fat required in the body?

A

energy source, essential polyunsaturated fatty acids (those needed but cannot be made by body) and absorption of fat soluble vitamins

28
Q

Different types of lipids

A

Simple lipids
Compound lipids
Steroids

29
Q

Features of lipids

A
  • usually hydrocarbons
  • contain long chain fatty acids
  • insoluble in water
30
Q

Examples of simple lipids

A

fatty acids
triglycerides
waxes

31
Q

examples of compound lipids

A

phospholipids, glycolipids, lipoproteins

32
Q

examples of steroids

A

cholesterol, steroid hormones eg adrogens

33
Q

What is the main energy storage form in adipose tissue?

A

Triglycerides (triacylglycerols)

34
Q

Structure of triglycerides

A

Glycerol and 3 fatty acids

35
Q

Fatty acids are aliphatic. T/F?

A

True, they have no rings

36
Q

Double bonds of fatty acids are usually in trans configuration. T/F

A

False

Cis

37
Q

All fatty acids are liquid at room temperature. T/F?

A

False

Liquid up to 8 C atoms, longer ones are solid

38
Q

Impact of presence of double bonds on melting point

A

Lowers melting point

39
Q

Why are plant acids liquid?

A

they contain large proportions of unsaturated fatty acids

animal fats are solid as they mostly contain palmitic and stearic acid

40
Q

Main products of fat digestion

A

Glycerol, fatty acids and monoglycerides

41
Q

Which cells absorb fat in the intestine?

A

Mucosal cells

42
Q

Chylomicrons

A

Lipoproteins coated with a layer of protein, phospholipid and cholesterol

43
Q

Enzyme involved in llipolysis

A

Hormone sensitive lipase, which release free fatty acids and glycerol

44
Q

What must happen before fatty acids can be oxidised to generate energy?

A

They must be converted to CoA derivatives

45
Q

Where does initiation of fatty acid oxidation occur?

A

in the cytoplasm

further oxidation occurs in the mitochondrial matrix

46
Q

The carnitine shuttle

A

Fatty acids in cytoplasm are transferred from Acyl-CoA to carnitine (a transporter in inner membrane) and moves acyl-CoA to mitochondrial matrix

47
Q

Beta oxidation

A

Cycle of reactions which occurs in the mitochondrial matrix

Consists of four steps per cycle

48
Q

Products of each cycle of beta oxidation

A
  • 1 acetyl-CoA
  • 1 FADH2
  • 1 NADH + H+
  • 1 fatty acyl-CoA, shortened by 2 C atoms
49
Q

Breakdown of glycerol

A

glycerol kinase causes activation to glycerol-3-phosphate

it is then dehydrogenated to dihydroxyacterone phosphate

50
Q

Where are ketone bodies formed?

A

In liver mitochondria from acetyl-CoA from B oxidation

51
Q

Role of ketone bodies

A

molecules of energy metabolism for heart muscle and renal cortex

It is converted back to acetyl-CoA which enters TCA cycle

52
Q

Ketosis in starvation and diabetes

A

oxaloacetate is consumed for gluconeogenesis
fatty acids are oxidised to provide energy
acetyl-CoA is converted to ketone bodies
high levels in blood
too much for extrahepatic tissue (i.e. heart, brain, etc.)
ketone bodies are moderate acids
accumulation leads to severe acidosis (blood can’t buffer any more)
impairs tissue function, particularly central nervous system
smell of acetone can be detected in breath

GI (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions