6) Lipids & lipoproteins Flashcards

1
Q

4 lipid functions

A
  • Main source of energy and energy storage
  • Converted to hormones or hormone precursors
  • Serve as structural and functional components of cell membranes
  • Provide insulation for nerve conduction and heat retention
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2
Q

5 lipid classes

A
  • Sterol derivatives
  • Fatty acids
  • Glycerol esters
  • Sphingosine derivatives
  • Terpenes
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3
Q

4 sterol derivatives

A
  • Cholesterol and cholesteryl esters
  • Steroid hormones
  • Bile acids
  • Vitamin D
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4
Q

3 size classifications of FAs

A

Short chain (2-4 C atoms)
Medium chain (6-10 C atoms)
Long chain (12-26 C atoms)

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5
Q

terpenes

A

Vitamin A
Vitamin E
Vitamin K

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6
Q

Contains 27 carbon atoms and four fused rings (A, B, C, and D) called the perhydrocyclopentanophenanthrene nucleus.

A

cholesterol

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7
Q

3 main functions of cholesterol

A
  • Structural component of cell membranes
  • Precursor of bile acids
  • Precursor of Vitamin D and steroid hormones
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8
Q

2 forms of cholesterol

A

exogenous
endogenous

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9
Q

Cholesterol is solubilized by the formation of mixed ——-

A

micelles

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10
Q

If the amount of cholesterol ….. then a supersaturated state can occur that results in the formation of gallstones

A

exceeds the capacity of solubilizing agents

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11
Q

FA nomenclature

A

methyl end = omega end
number for double bond position

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12
Q

Derivatives of fatty acids comprising 20 C atoms, including a five-carbon cyclopentane ring

A

prostaglandins

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13
Q

4 functions of prostaglandins

A
  • Contraction and relaxation of smooth muscle
  • Dilation and constriction of blood vessels
  • Control of blood pressure
  • Modulation of inflammation
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14
Q

comprise 95% of fat stored in tissue

A

TGs

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15
Q

lecithins

A

phospholipids

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16
Q

Important component of the myelin sheath

A

sphingomyelin

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17
Q

5 components of a lipoprotein

A
  • An outer layer of proteins
  • Apolipoproteins
  • Polar lipids (phospholipids)
  • Unesterified cholesterol
  • An inner core of neutral lipids (phospholipids and esterified cholesterol).
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18
Q

These are receptor sites or the “address tags” to tell the lipoprotein where to go in the body

A

apolipoproteins

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19
Q

Form the major proteins in HDL and in chylomicrons

A

Apo-A

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20
Q

This is the major protein for LDL and VLDL. This binds LDL to LDL receptors.

A

Apo-B

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21
Q

This lipoprotein helps in metabolism of triglyceride rich lipoproteins

A

Apo-C

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22
Q

This lipoprotein may function as a transfer protein to assist in the movement of cholesterol and triglycerides between LDL and HDL.

A

Apo-D

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23
Q

Important in recognition and catabolism of chylomicrons and remnant IDL.

A

Apo-E

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24
Q

4 pathways of lipoprotein metabolism

A

Lipid absorption
Exogenous
Endogenous
Reverse cholesterol

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25
Q

Triglycerides: 84%
Apolipoproteins: 1–2%
Cholesterol: 7%
Phospholipids: 6%

A

chylomicrons

26
Q

Triglycerides: 44–60%
Cholesterol: 16–22%
Apolipoproteins: 2–8%
Phospholipids: 18%

A

VLDL

27
Q

Triglycerides: 25%
Cholesterol: 38%
Apolipoproteins: 11%
Phospholipids: 26%

A

IDL

28
Q

Triglycerides: 11%
Cholesterol: 62%
Apolipoproteins: 20%
Phospholipids: 23%

A

LDL

29
Q

Triglycerides: 3%
Cholesterol: 19%
Apolipoproteins: 50%
Phospholipids: 25–30%

A

HDL

30
Q

short vs long chain FA transportation

A

Short-chains are carried by albumin to the liver
Long-chains are packaged into chylomicrons

31
Q

Composed of the metabolism of chylomicrons

Responsible for transporting dietary or exogenous fat, mostly triglycerides, from the intestines to the liver and peripheral cells

A

exogenous pathway

32
Q

chylomicron plasma appearance

A

turbid
creamy layer after ultracentrifuge or sitting at RT

33
Q

chylomicron Apo

A

Apo A
Apo B-48
Apo C-II
Apo E

34
Q

Involves the metabolism of very-low-density lipoproteins (VLDL) to intermediate density lipoproteins (IDL) to low-density lipoproteins (LDL)

A

endogenous pathway

35
Q

VLDL plasma appearance

A

turbid
no creamy layer after ultracentrifugation

36
Q

VLDL Apo

A

Apo B-100
Apo C-II
Apo E

37
Q

Can be elevated in patients with type III hyperlipoproteinemia, a rare inborn error of metabolism

A

IDL

38
Q

IDL Apo

A

Apo B-100
Apo E

39
Q

IDL function

A

Transports triglycerides and cholesterol to the liver from peripheral tissues.

40
Q

LDL function

A

Major transporter of cholesterol in plasma to peripheral tissues

41
Q

LDL Apo

A

Apo B-100

42
Q

HDL function

A

reverse cholesterol transport
Cholesterol scavenger that removes cholesterol from tissues and carries it to the liver for disposal

43
Q

HDL Apo

A

Apo A-I
Apo C-II
Apo E

44
Q

Independent, causal risk factor for atherosclerosis

Highly heritable

A

Lipoprotein (a)

45
Q

LipoProtein Lipase (LPL) Deficiency

A

I. Familial Hyperchylomicronemia

46
Q

LDL Receptor Mutations
(Deficiency)
ApoB-100 Mutations

A

IIa. Familial
Hypercholesterolemia

47
Q

LDL Receptor Mutations
Overproduction of VLDL and ApoB-100

A

IIb. Familial Combined Hyperlipidemia.

48
Q

ApoE Deficiency
(Abnormal IDL metabolism)

A

III. Familial
dys-beta-lipoproteinemia

49
Q

Overproduction of VLDL

A

IV. Familial Hypertriglyceridemia

50
Q

Abnormal VLDL & chylomicron metabolism

A

V. Familial mixed Hypertriglyceridemia

51
Q

Has been associated with hyperthyroidism and hepatocellular disease

Malnutrition, starvation, and eating disorders (anorexia, bulimia)

abetalipoproteinemia

A

hypocholesterolemia

52
Q

Associated with acute pancreatitis as both a precipitant and an epiphenomenon

A

hypertriglyceridemia

53
Q

A very rare condition that affects fat and vitamin absorption by the intestines and liver, leading to very low LDL-cholesterol and malnutrition.

A

abetalipoproteinemia

54
Q

enzymes used in cholesterol methodology

A

cholesterol esterase
cholesterol oxidase

55
Q

Classic method and can separate/fractionate all lipoproteins

A

Analytical ultracentrifugation

56
Q

Heparin-manganese-chloride (method of choice)
Dextran sulfate-magnesium chloride
Sodium phosphotungstate Mg2+

A

used in selective precipitation
HDL left in solution

57
Q

Uses an antibody to Apo B-100 to bind LDL and VLDL.

A

Homogenous enzyme assays
(block non-HDL)

58
Q

Friedewald formula for indirect LDL

A

LDL = total cholesterol - (HDL + TG/5)

TG/5 = VLDL

59
Q

cannot use indirect LDL method if…

A

TG level is over 400 mg/dL
High amount of chylomicrons
Dysbetalipoproteinemia

60
Q

TG methodologies use enzyme…

A

lipase

61
Q

Group of interrelated metabolic risk factors that appear to directly promote the development of atherosclerotic cardiovascular disease

A

metabolic syndrome

62
Q

criteria for metabolic syndrome

A

Must have 3:
- Increased waist circumference (>40 in men; >35 in women)
- Elevated triglycerides (>150 mg/dL; or on TG meds)
- Low HDL-C (<40 mg/dL men; <50 mg/dL women; or on HDL meds)
- Elevated blood pressure (>130/85; or on HTN meds)
- Elevated fasting glucose (>100 mg/dL; or on DM meds)