Brainscape's Knowledge GenomeTM

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


See full index

Biochem > FA Oxidation and Ketone Bodies > Flashcards

FA Oxidation and Ketone Bodies Flashcards

1
Q

FA oxidation occurs where?

A

in mitochondria

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

True or false? Long-chain FAs can’t enter the mitochondria without transport mechanisms. Medium and short-chain FAs can enter by diffusion.

A

true

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

Medium-chain and short-chain FAs are more water soluble. They are not incorporated into ____. They enter the portal blood and are transported primarily to the ____ where they enter by _____.

A

chylomicrons; liver; diffusion

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

In the mitochondria, medium and short-chain FAs are activated to ___-___ for beta-oxidation

A

acyl-CoAs

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

FA binding proteins in the plasma membrane aid in the transport of long-chain FAs from ___ in the blood

A

albumin

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

Long-chain FAs enter the mitochondria as fatty _____

A

acylcarnitines

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

A fatty acyl-CoA synthase on the ___ mitochondrial membrane produces acyl-CoAs which enter the mitochondrial ____-membrane space

A

outer; inter

note: CPT I catalyzes this reaction

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

_____ are transported across the mitochondrial inner membrane in exchange for “free” _____ by cranitittine:acylcarnitine translocase

A

acylcarnitines; carnitine

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

Inside the mitochondria, the acyl-CoA is “____” by CPT II

A

“regenerated”

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

Beta-oxidation of long-chain acyl-CoAs is a series of 4 reactions repeated cyclically. Each cycle produces how many acetyl-Coa, FADH2, NADH, and acyl-CoA

A

acetyl-CoA: 1
FADH2: 1
NADH: 1
acyl-CoA: one reduced in length by 2 carbons

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

Since the 4 reactions of beta-oxidation occur inside the mitochondria, the reduced cofactors are substrates for ____ ____, and the acetyl-CoA is a substrate for the ____ ____

A

oxidative phosphorylation; TCA cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q 
Each of the 4 reactions in beta-oxidation is catalyzed by a number of enzymes which have various specificities for chain length. For the following acyl-CoA dehydrogenase, give the light of chain it prefers.
VLCAD
LCAD
MCAD
SCAD
A

VLCAD: prefers C12 to C24
LCAD: C12 to C16
MCAD: C6 and C8
SCAD: C4>C6>C8

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

The major control of beta-oxidation is exerted at which enzyme?

A

CPT I

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

CPT I is inhibited by ____-___

A

malonyl-CoA

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

Malonyl-CoA is the produce of ___-___ carboxylase and is the substrate for FA ____

A

acetyl-CoA; synthesis

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

Acetyl-CoA carboxylase is stimulated (malonyl-CoA is produced) in what situation?

A

when insulin predominates

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

Acetyl-CoA carboxylase is inhibitied (malonyl-CoA concentration decreases) in what situation?

A

when glucagon predominates

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

How do odd-numbered FAs go through Beta-oxidation?

A
  1. at the final stage, one molecule of acetyl-CoA and one molecule of propionyl-CoA are produced
  2. propionyl-CoA is converted to succinyl-CoA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

____-___ is a gluconeogenic precursor, and thus the only part of a FA which can result in the net synthesis of glucose

A

Succinyl-CoA

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

Oxidation of unsaturated FAs have to be handled differently because the double bonds are in the ____ configuration and may involve an ___-numbered carbon

A

cis; odd

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

Unsaturated FAs are oxidized with help from two enzymes. What are they?

A
  1. enoyl-CoA isomerase

2. 2,4-dienoyl-CoA reductase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where does oxidation of very long chain FAs (C24-C26) occur?

A

peroxisomes

note: called “modified” beta-oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the products of very long chain FA “modified” beta oxidation?

A

acetyl-CoA and a fatty acyl-CoA reduced by 2 carbons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The acyl-CoA oxidation in modified beta oxidation is not linked to cofactor ____

A

reduction; means no energy is provided by this step

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The peroxisomal oxidation (modified beta oxidation) proceeds until the acyl-CoA is about ___ carbons long

A

8

26
Q

The octanoyl-CoA and the acetyl-CoA produced by peroxisomal oxidation are transported to the ____ for further oxidation

A

mitochondria

27
Q

True or false? animals do not produce branched-chain fatty acids

A

true

28
Q

The most common long-chain branched FA is a degradation product of ____

A

chlorophyll

29
Q

long-chain branched FAs are oxidized where?

A

peroxisomes

30
Q

What are the products of long-chain branched FA oxidation?

A
  1. CO2
  2. propionyl-CoA
  3. acetyl-CoA
31
Q

In regards to w-oxidation of FAs, the w-carbon is the terminal ___ group of the FA

A

methyl

32
Q

w-oxidation occurs where? requires what?

A

occurs in ER

requires cytochrome P450, O2, and NADPH

33
Q

The w-CH3 group is oxidized first to an ____ and then to a ____ ___

A

alcohol; carboxylic acid

note: produces a dicarboxylic acid

34
Q

The w-oxidation pathway is though to function to produce more water-soluble compounds from water insoluble FAs. The products may be oxidized as ___-chain FAs or they can be ___

A

medium; excreted

35
Q

Ketone bodies are formed from ___-___ from FA oxidation

A

acetyl-CoA

36
Q

Name the 3 ketone bodies

A

acetoacetate, beta-hydroxybutyrate; acetone

37
Q

The ketone bodies are synthesized in ____ ____

A

liver mitochondria

38
Q

___-___ is an intermediate in the ketone body pathway

A

HMG-CoA

39
Q

The liver mitochondrial HMG-CoA synthase is an isozyme restricted to the mitochondria and functions only in what?

A

synthesis of ketone bodies

40
Q

The cytosolic HMG-CoA synthase of many cells is the isozyme of ____ synthesis

A

cholesterol

41
Q

Ketone bodies are utilized by peripheral tissues for energy - primarily the ___ and ____

A

muscle and brain

note: the enzymes are mitochondrial

42
Q

The ___ only produces ketone bodies, and the ___ ___ only utilizes ketone bodies

A

liver; peripheral tissue

43
Q

Only liver mitochondria contain the enzymes specific for the synthesis of ketone bodies. What are they?

A
  1. mitochondrial HMG-CoA synthase

2. HMG-CoA lyase

44
Q

Peripheral tissues (muscle and brain) express the enzyme specific for utilization of ketone bodies. What is it?

A

acetoacetate: succinyl-CoA transferase

45
Q

True or false? ketone bodies are formed in the liver only when the liver is supplied with high concentrations of FAs

A

true

46
Q

Where do the FAs used to synthesize ketone bodies come from?

A

lipolysis of adipose tissue

47
Q

In what individuals is ketone body production usually seen?

A

starving or uncontrolled type 1 diabetes

48
Q

After an over night fast, the concentration of ketone bodies in the blood is on the order of ____ mM. After a 2 day fast? After 40 days of starvation?

A

overnight: 0.05
2 days: 2mM
40 days: 7mM

49
Q

____ is derived from the spontaneous, non-enzymatic decarboxylation of acetoacetate

A

acetone

50
Q

The amount of FAs provided to the liver is under the control of ____ and ____

A

insulin and glucagon

51
Q

This is the most common genetic disease of lipid metabolism (1/15000). It is associated with non-ketotic hypoglycemia upon fasting, fatty infiltration of liver, and short chain dicarboxylic acids in urine

A

MCAD (medium-chain acyl-CoA dehydrogenase) deficiency

52
Q

In regards to MACD, non-ketotic hypoglycemia upon fasting may be deadly in an overnight fast of which individuals?

A

children

53
Q

In regards to MACD, Fatty acids which cannot be oxidized are assembled into ____ which exceed the ability of the liver to secrete as ___

A

TAG; VLDL

54
Q

In regards to MACD, the short chain dicarboxylic acids in the urine arise from where?

A

w-ocidation of medium and short chain fAs which can’t be oxidized by beta-oxidation

55
Q

What is the treatment of MACD?

A

avoid fasting

56
Q

In this disorder of lipid oxidation, insufficient FAs are delivered into the mitochondria. Symptoms include non-ketotic hypoglycemia due to decreased energy for gluconeogenesis

A

carnitine deficiency

57
Q

In this disorder of lipid oxidation, symptoms include non-ketotic hypoglycemia due to decreased beta-oxidation, hepatomegaly with fatty infiltration, increased plasma carnitine. It can be overcome by medium-chain FAs

A

CPT I deficiency

58
Q

This disorder of lipid oxidation can be described by a rare genetic deficiency of a component required for peroxisomal oxidation of branched-chain FAs. Its associated with serious neurological issues.

A

Refsum disease

59
Q

How is Refsum disease treated?

A

by reducing phytanic acid from diet (restrict dairy and meat)

60
Q

This disorder of lipid oxidation is due to eating the unripe fruit of the akee tree, which contains hypoglycin - It is a potent inhibitor of acyl-CoA dehydrogenase. Symptoms are non-ketotic hypoglycemia

A

Jamaican vomitting sickness

note: one case reported a blood glucose concentration of 3 mg/dl

Biochem (38 decks)

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