Metabolism of Dietary Lipids Flashcards Preview

Biochem II > Metabolism of Dietary Lipids > Flashcards

Flashcards in Metabolism of Dietary Lipids Deck (59):
1

List the different classes of lipids (5)

Fatty Acids
Triaclyglycerol
Phospholipid
Steroids
Glycolipids

2

What makes up a TAG?

Glycerol and 3 fa

3

Fatty acids usually contain an organic acid group. What is the name of this acid?

Carboxylic acid

4

What makes up a phospholipid?

glycerol, 2 fa, and at least 1 phosphate group

5

What type of enzymes will break down lipids?

Lipases and esterases

6

What type of fatty acid chains do lipase's usually digest and where in the body does this occur?

Short fatty acid chains TAGS in the stomach

7

Where is the gastric endocrine system activated?

The duodenum

8

What enzyme will catalyze the hydrolysis of lipids containing fa

Pancreatic Lipases

9

What substance of the body all help to emulsify lipids and what is the general mechanism?

Bile
They increase reactive surface area by decreasing clumping.

10

Where are bile salts made, stored, and delivered in the body?

Made: liver
Stored: gall bladder
Delivered: duodenum

11

Do both gastric and lingual lipase's hydrolyze ester bonds in short and medium chain TAGS?

Yes!

12

Bile salts are derivatives of what steroid compound?

Cholesterol

13

What hormone will activate the secretion of bile?

Cholecystokinin CKK

14

The target for the pancreatic enzymes include:

TAG(lipase), Cholesterol ester(esterase), phospholipid digestion(lipase)

15

What hormone is secreted in response to protein/lipids in the small intestine?

Cholestystokinin

16

Name a few functions of Cholestystokinin

Decreases gastric emptying, increases bile secretion and the secretion of zymogens activated by trypsin

17

Secretin acts on what cells in the body?

Pancreas exocrine cells

18

What does secretin secrete?

Bicarbonate to increase pH

19

What is the function of the chylomicron?

Delivers food derived fatty acids from the intestine to the cell.

20

Where are the chylomicrons assembled and secreted to?

In enterocytes and secreted to the lymph system.

21

If a fatty acid has no double bonds it is called?

Saturated

22

Fatty acids that are used for structure such as cellular membranes generally have how many carbons?

16

23

Fatty acids with double bonds in biological systems are usually in what conformation?

Cis

24

Fatty acids with chains lengths of 4 to 10 are found in what liquid?

Milk

25

What 2 hormones control the release of fatty acids from adipocytes?

Glucagon and epinephrine

26

Glucagon and epinephrine will bind to what part of the cell and will activate a signal cascade of what kind of enzyme?

Both bind a receptor on the cell membrane of adipocyte activating protein kinase A (PKA)

27

By what mechanism does PKA activate the hormone sensitive lipase?

Phosphorylation

28

How are fatty acids carried in the blood stream?

Serum Albumin

29

In the case where there are more than one double bond the double bonds usually spaced by at least how many carbons?

3

30

What are the two essential fatty acids that we cannot synthesize?

Linoleic and alpha-linolenic acid

31

In humans where does fatty acid synthesis occur?

Lactating mammary glands
Liver
Adipose tissues

32

What 3 things does fatty acid synthesis require?

Reduced NADPH
Acetyl CoA
ATP

33

What does acetyl CoA require to pass through the inner mitochondrial membrane?

A citrate to pyruvate shuttle

34

Where do we obtain mitochondrial CoA?

1) pyruvate, 2) ketone bodies, 3) fatty acid breakdown (β-oxidation) and 4) some amino acids

35

What is the rate limiting step of fa synthesis?

Carboxylation of Acetyl CoA to form Malonyl CoA

36

What intermediate can cause ACC to polymerize and activates it?

Citrate

37

What will deactivate ACC?

Long chain fatty acyl CoA (palmitic acyl CoA) the end product of fatty acid synthesis

38

A continuous diet of excessive calories will cause and increase in...

acetyl CoA carboxylase enzyme synthesized. This will increase fatty acid synthesis.

39

The major pathway for catabolism of fatty acids is called?

Beta-oxidation

40

In Beta-oxidation how many carbon fragments are removed at a time?

2

41

What are the end products of beta-oxidation?

acyl CoA
NADH
FADH2

42

What is used to move acyl CoA into the mitochondria?

Carnitine Shuttle

43

What happens to the acyl group with the Carnitine Shuttle?

- the acyl group is transferred to the carnitine via carnitine palmitoyl transferase I an enzyme on the outside membrane of the mitochondria.

44

The acyl carnitine will pass through the inner membrane in exchange for what?

In exchange for free carnitine which passes outside the inner mitochondrial through the same Translocase transporter that acyl-carnitine passed through.

45

Once inside the mitochondria how is the acyl group freed?

By the enzyme carnitine palmitoyl transferase II (CPT2)

46

What is the energy production from β-oxidation of one palmitoyl CoA?

It yields 8 acetyl CoA, 7 NADH and 7 FADH2 from which 131 ATP can be generated.

47

What is the total net ATP production of Beta-oxidation?

129 ATP

48

The oxidation of saturated or unsaturated yields more energy?

Saturated

49

What happens to very long fatty acids during catabolism?

They undergo a preliminary β-oxidation in peroxisomes.

50

What is the name of the 3 carbon odd numbered fatty acid?

Propionyl-CoA

51

The enzymes to process propionyl-CoA will require other co-enzymes and co-factors what are they?

The carboxylase requires Biotin and ATP
The mutase requires Vit B12

52

Propionyl-CoA will be converted to what compound and enters what cycle?

Succinyl CoA - TCA cycle

53

Where does omega-oxidation occur in the body?

Endoplasmic reticulum of liver/kidney

54

Acetone, and d-beta-hydroxybutyrate and acetoacetate are examples of what type of molecules?

Ketones

55

T or F
The liver can easily metabolize ketone bodies

False

56

Ketone bodies have the potential to produce how many ATP?

24

57

When are ketone bodies produced?

When acetyl CoA in the liver is in excess of the livers oxidative capacity.

58

What are the two key enzymes in fatty acid synthesis?

Acetyl CoA Carboxylase
Fatty Acid Synthase

59

T or F
Acetyl CoA cannot pass through the mitochondrial membrane to be used in the cytosol.

True