Brainscape's Knowledge GenomeTM

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


See full index

GB > 11. Post Absorption Processing of Lipids > Flashcards

11. Post Absorption Processing of Lipids Flashcards

1
Q

What are lipids transported in in circulation?

A

Lipoprotein particles: chylomicrons

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

What is fat principally absorbed as?

A

2-monoacylglycerol

FAs

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

What are FAs converted to?

A

Acyl-CoA

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

Where are FAs converted to Acyl-CoA?

A

ER of intestinal mucosal cells

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

What converts FAs to acyl-CoA?

A

Acyl-CoA Synthetase

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

What happens once proteins and lipids are secreted from the smooth ER and golgi?

A

Released into extracellular space as fat droplets
Collected by local lymph
Transported via the thoracic duct to the left brachycephalic vein

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

What is the structure of monoacylglycerol?

A

Glycerol linked to a FA via an ester bond

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

What is the structure of triacylglycerol?

A

Ester derived from glycerol and 3 FAs

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

What is the structure of cholesterol ester?

A

Ester bond formed between the carboxylate group of a fatty acid and the hydroxyl group of cholesterol

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

What does utilisation of TAGs require?

A

Lipoprotein Lipase

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

Where is lipoprotein lipase not found?

A

Liver

Brain

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

What is LPL attached to?

A

Heparan sulphate glycoproteins on the surface of the capillary endothelium on adipose

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

What increases the activity of LPL?

A

Insulin

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

What happens to TAGs when going from a fed state to a fasting one?

A

TAGs are re-routed from adipose to muscle

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

Where do most of the FAs used in TAG synthesis in adipose tissue come from?

A

Chylomicrons

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

Where do most of the FAs used in TAG synthesis after a high carb meal come from?

A

Acetyl CoA

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

What form do FAs participate in TAG synthesis as?

A

CoA-thioesters

18
Q

What form does glycerol participate in TAG synthesis as?

A

Glycerol-3-phosphate

19
Q

How does insulin regulate fat synthesis?

A

Increases rate of glycolysis
Increases LPL activity
Induces glycerolphosphate-acyl transferase which catalyses the first step in TAG synthesis

20
Q

What enzyme carries out the first cleavage of a FA from TAGs?

A

Hormone-sensitive adipose tissue lipase

21
Q

What activates adipose tissue lipase?

A

Phosphorylation by cAMP-dependent Protein Kinase A

22
Q

What are the most important human lipolytic agents?

A

Noradrenaline and adrenaline

23
Q

How does noradrenaline work to promote TAG breakdown?

A

Acts via beta-adrenergic receptors, cAMP, Protein Kinase A

24
Q

What are other lipolytic hormones?

A

Glucocorticoids
GH
Thyroid hormone

25
Q

What conditions increase TAG hydrolisation?

A

Cold exposure
Stress
Physical exercise

26
Q

What do free FAs bind to in circulation?

A

Albumin

27
Q

Where does beta oxidation occur?

A

In the mitochondrion

28
Q

What types of cells can’t oxidise FAs?

A

Neurons

Erythrocytes

29
Q

How do short FAs enter the mitochondrion?

A

Passive diffusion

30
Q

How do longer FAs enter the mitochondrion?

A

Converted to CoA-thioesters by Fatty Acyl CoA Synthetase
Carnitine transports acyl group across the membrane
Known as the carnitine shuttle

31
Q

What is the carnitine shuttle composed of?

A

Carnitine Palmitoyltransferase 1 and 2

Carnitine-acylcarnitine translocase

32
Q

What inhibits CPT-1?

A

Malonyl-CoA

33
Q

What is the net result of beta oxidation?

A

Each cycle removes 2 carbons from the FA as acetyl-CoA

Production of NADH, H+ and FADH2

34
Q

How does beta oxidation produce energy?

A

FADH2 and NADH feed into oxidative phosphorylation

Acetyl-CoA enteres TCA cycle

35
Q

How is beta oxidation regulated?

A

Supply of free FAs
Activity of hormone-sensitive adipose tissue lipase
Inhibted by malonyl-CoA

36
Q

Name 3 ketone bodies

A

Acetoacetate
B-hydroxybutyrate
Acetone

37
Q

How are acetoacetate and B-hydroxybutyrate formed?

A

From Acetyl-CoA in the liver mitochondria by ketogenesis

38
Q

How is acetone formed?

A

Spontaneous decarboxylation of acetoacetate

39
Q

Where are ketone bodies especially important for energy?

A

Heart
Adrenal glands
Renal cortex

40
Q

When are circulating ketone body levels high?

A

Fasting
Diabetes mellitus
Whenever fat breakdown exceeds carbohydrate breakdown

41
Q

What is brown adipose tissue characterised by?

A

Good blood supply
High mitochondria and cytochromes
Low activity of ATP synthetase

42
Q

What are the main clinical signs of Medium Chain Acyl-CoA Dehydrogenase Deficiency?

A 
Intolerance to prolonged fasting
Hypoglycaemia
Impaired ketogenesis
Hypoglycaemic coma
Medium-chain dicarboxylic aciduria

GB (15 decks)

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