Brainscape's Knowledge GenomeTM

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


See full index

Step 1 2019 First Aid Flashcards > Biochem FA - p85 - 94 Metabolism > Flashcards

Biochem FA - p85 - 94 Metabolism Flashcards

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

In skeletal muscle, glycogen converted to?

A

Glycogen undergoes glycogenolysis–> glucose-1-phosphate –> glucose-6-phosphate

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

First step of glycogenolysis

A

Glycogen phosphorylase liberates glucose-1-phosphate residues off branched glycogen until 4 glucose units remain on a branch.

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

T or F Glycogen is only degraded in the cytosol

A

F - A small amount of glycogen is degraded in lysosomes by α-1,4-glucosidase (acid maltase).

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

What happens once glycogen phosphorylase has done its job?

A

Then 4-α-d-glucanotransferase (debranching enzyme ) moves 3 of the 4 glucose units from the branch to the linkage. Then α-1,6-glucosidase (debranching enzyme ) cleaves off the last residue, liberating glucose.

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

Name the types of Glycogen storage disease (I, II, III, and V) and what the enzyme deficiency is

A

Von Gierke - G6Pase

Pompe - acid maltase (Lysosomal acid α-1,4glucosidase with α-1,6-glucosidase activity)

Cori disease - Debranching enzyme (α-1,6-glucosidase)

McArdle - Skeletal muscle glycogen phosphorylase (Myophosphorylase)

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

Treatment: frequent oral
glucose/cornstarch; avoidance
of fructose and galactose
Impaired gluconeogenesis and
glycogenolysis

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

PomPe trashes the PumP (1st and 4th letter; heart, liver, and muscle)

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

Gluconeogenesis is intact

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

Blood glucose levels typically
unaffected
McArdle = Muscle

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

Findings

A

Progressive neurodegeneration,
developmental delay, hyperreflexia,
hyperacusis, “cherry-red” spot on
macula A , lysosomes with onion
skin, no hepatosplenomegaly (vs
Niemann-Pick).

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

deficient enzyme

A

heXosaminidase A

(“TAy-SaX)

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

Accumulated Substrate

Inheritance

A

GM2 ganglioside

AR

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

findings

A

Early: triad of episodic peripheral
neuropathy, angiokeratomas B ,
hypohidrosis.
Late: progressive renal failure,
cardiovascular disease.

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

deficient enzyme

A

α-galactosidase A

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

accumulated subtrate

inheritance

A

Ceramide
trihexoside
(globotriaosylceramide)

XR

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

Metachromatic
leukodystrophy

findings

A

Central and peripheral demyelination
with ataxia, dementia.

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

Metachromatic
leukodystrophy

deficient enzyme

A

Arylsulfatase A

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

Metachromatic
leukodystrophy

accumulated substrate

inheritance

A

Cerebroside sulfate

AR

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

Krabbe disease

findings

A

Peripheral neuropathy, destruction
of oligodendrocytes, developmental
delay, optic atrophy, globoid cells.

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

Krabbe disease

deficient enzyme

A

Galactocerebrosidase

(galactosylceramidase)

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

Krabbe disease

accumulated substrate

inheritance

A

Galactocerebroside, psychosine

AR

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

Findings

A

Most common.
Hepatosplenomegaly, pancytopenia,
osteoporosis, avascular necrosis of
femur, bone crises, Gaucher cells C
(lipid-laden macrophages resembling
crumpled tissue paper).

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

deficient enzyme

A

Glucocerebrosidase
(β-glucosidase); treat
with recombinant
glucocerebrosidase

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

accumulated substrate

inheritance

A

glucocerebroside

AR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

findings

A

Progressive neurodegeneration,
hepatosplenomegaly, foam cells
(lipid-laden macrophages) D ,
“cherry-red” spot on macula A .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

deficient enzyme

A

sphingomyelinase

No man picks (Niemann-Pick) his nose with
his sphinger (sphingomyelinase).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

accumulated substrate

inheritance

A

sphingomyelin

AR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Hurler syndrome findings

A

Developmental delay, gargoylism,
airway obstruction, corneal clouding,
hepatosplenomegaly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Hurler syndrome deficient enzyme

A

α-l-iduronidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Hurler syndrome :

accumulated substrate

inheritance

A

Heparan sulfate,
dermatan sulfate

AR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Hunter syndrome findings

A

Mild Hurler + aggressive behavior, no
corneal clouding.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Hunter syndrome deficient enzyme

A

Iduronate-2-sulfatase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Hunter syndrome:

Accumulated substrate

inheritance

A

Heparan sulfate,
dermatan sulfate

XR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Fatty acid synthesis requires transport of _______
from __________ to ______. Predominantly
occurs in ______, _____ _________ ______, and
______ _______.

A

Fatty acid synthesis requires transport of citrate
from mitochondria to cytosol. Predominantly
occurs in liver, lactating mammary glands, and
adipose tissue.

“SYtrate” = SYnthesis.

36
Q

Long-chain fatty acid (LCFA) degradation
requires _______-________ transport into the
___________ _______.

A

Long-chain fatty acid (LCFA) degradation
requires carnitine-dependent transport into the
mitochondrial matrix.

CARnitine = CARnage of fatty acids.

37
Q
A
38
Q

Systemic 1° carnitine deficiency—

_______ defect in transport of ______ into the
_________ –>Ž toxic accumulation. Causes
________, ________, and ________ ________.

A

Systemic 1° carnitine deficiency—

inherited defect in transport of LCFAs into the
mitochondria Ž toxic accumulation. Causes
weakness, hypotonia, and hypoketotic
hypoglycemia.

39
Q

Medium-chain acyl-CoA dehydrogenase
deficiency—

___ ability to break down _____

_____ into acetyl-CoA Ž accumulation
of fatty acyl ______ in the blood with
_______ _______.

A

Medium-chain acyl-CoA dehydrogenase
deficiency—

dec ability to break down fatty
acids into acetyl-CoA Ž accumulation
of fatty acyl carnitines in the blood with
hypoketotic hypoglycemia.

40
Q

Medium-chain acyl-CoA dehydrogenase
deficiency—

Causes _____, _____, ______, ______, ______ ______, ______.

Can lead to ______ ______in infants or children.

Treat by avoiding ______.

A

Medium-chain acyl-CoA dehydrogenase
deficiency—

Causes vomiting, lethargy, seizures, coma, liver dysfunction, hyperammonemia.

Can lead to sudden death in infants or children.

Treat by avoiding fasting.

41
Q

In the _____, fatty acids and amino acids
are metabolized to _____and
_____(to be used in muscle and brain).

A

In the liver, fatty acids and amino acids
are metabolized to acetoacetate and
β-hydroxybutyrate (to be used in muscle and brain).

42
Q

In prolonged starvation and diabetic ketoacidosis, _____ is depleted for gluconeogenesis.

In alcoholism, excess _____ shunts oxaloacetate to _____ .

All of these processes lead to a buildup of _____ ,
which is shunted into ketone body synthesis.

A

In prolonged starvation and diabetic ketoacidosis, oxaloacetate is depleted for gluconeogenesis.

In alcoholism, excess NADH shunts oxaloacetate to malate.

All of these processes lead to a buildup of acetyl-CoA,
which is shunted into ketone body synthesis.

43
Q

Ketone bodies: _____, _____, _____.
Breath smells like _____(fruity odor).
Urine test for ketones can detect _____, but not _____.
RBCs cannot utilize ketones; they strictly use
_____.
HMG-CoA _____ for ketone production.
HMG-CoA _____ for cholesterol synthesis.

A

Ketone bodies: acetone, acetoacetate, β-hydroxybutyrate.
Breath smells like acetone (fruity odor).
Urine test for ketones can detect acetoacetate, but not β-hydroxybutyrate.
RBCs cannot utilize ketones; they strictly use
glucose.
HMG-CoA lyase for ketone production.
HMG-CoA reductase for cholesterol synthesis.

44
Q
A
45
Q

Fasting and starvation

Priorities are to supply sufficient _____ to the _____ and _____ and to preserve _____ .

A

Fasting and starvation

Priorities are to supply sufficient glucose to the brain and RBCs and to preserve protein.

46
Q

Fed state (after a meal)

_____ and _____ respiration.

_____ stimulates storage of _____ , _____ , and _____ .

A

Fed state (after a meal)

Glycolysis and aerobic respiration.

Insulin stimulates storage of lipids, proteins, and glycogen.

47
Q

Fasting (between meals)

Hepatic _____ (major); hepatic _____ , adipose release of _____ (minor).

_____ and _____ stimulate use of fuel reserves.

A

Fasting (between meals)

Hepatic glycogenolysis (major); hepatic gluconeogenesis, adipose release of FFA (minor).

Glucagon and epinephrine stimulate use of fuel reserves.

48
Q

Starvation days 1–3

Blood glucose levels maintained by:
ƒ-_____ glycogenolysis
ƒƒ-Adipose release of _____
ƒƒ-_____ and _____ , which shift fuel use from
_____ to FFA
ƒ-ƒHepatic _____ from peripheral tissue _____ and _____ , and from adipose tissue _____ and _____-_____ (from odd-chain FFA—the only triacylglycerol components that contribute to gluconeogenesis)

Glycogen reserves depleted after day _.
RBCs lack _____ and therefore cannot
use ketones.

A

Starvation days 1–3

Blood glucose levels maintained by:
ƒ-ƒHepatic glycogenolysis
ƒƒ-Adipose release of FFA
ƒƒ-Muscle and liver, which shift fuel use from
glucose to FFA
ƒ-ƒHepatic gluconeogenesis from peripheral tissue lactate and alanine, and from adipose tissue glycerol and propionyl-
CoA (from odd-chain FFA—the only triacylglycerol components that contribute to gluconeogenesis)

Glycogen reserves depleted after day 1.
RBCs lack mitochondria and therefore cannot
use ketones.

49
Q

Starvation after day 3

_____ stores (_____ _____ become the main source of energy for the brain). After these are depleted, vital protein degradation accelerates, leading to organ failure and death.
Amount of excess stores determines survival time.

A

Starvation after day 3

Adipose stores (ketone bodies become the main source of energy for the brain). After these are depleted, vital protein degradation accelerates, leading to organ failure and death.
Amount of excess stores determines survival time.
50
Q
A
51
Q

Cholesteryl ester transfer protein fxn

A

Mediates transfer of cholesterol esters to other lipoprotein particles.

52
Q

Hepatic lipase fxn

A

Degrades TGs remaining in IDL.

53
Q

Hormone-sensitive lipase fxn

A

Degrades TGs stored in adipocytes.

54
Q

Lecithin-cholesterol acyltransferase fxn

A

Catalyzes esterification of 2⁄3 of plasma cholesterol.

55
Q

Lipoprotein lipase fxn

A

Degrades TGs in circulating chylomicrons.

56
Q

Pancreatic lipase fxn

A

Degrades dietary TGs in small intestine.

57
Q

PCSK9 fxn

A

Degrades LDL receptor –> Inc serum LDL. Inhibition –> Inc recycling of LDL receptor –> decserum LDL.

Rx/ Alirocumab, evolocumab

58
Q

Apo E fxn

A

Mediates rEmnant uptake

(Everything Except LDL)

59
Q

Apo A-I fxn

A

Activates LCAT

60
Q

Apo C-II fxn

A

Lipoprotein lipase Cofactor that Catalyzes Cleavage

61
Q

Apo B-48 fxn

A

Mediates chylomicron secretion into lymphatics

Only on particles originating from the intestines

62
Q

Apo B-100 fxn

A

Binds LDL receptor

On VLDL, IDL, LDL

Only on particles originating from the liver

63
Q

If you have LCAT or A-1 def, then you have dec _____?

A

HDL

64
Q

Lipoprotein functions

Lipoproteins are composed of varying proportions of _____ , _____ , and _____ . _____ and _____ carry the most cholesterol.

Cholesterol is needed to maintain _____ _____ integrity and synthesize _____ _____ , _____ , and _____ _____ .

A

Lipoprotein functions

Lipoproteins are composed of varying proportions of cholesterol, TGs, and phospholipids. LDL and HDL carry the most cholesterol.

Cholesterol is needed to maintain cell membrane integrity and synthesize bile acids, steroids, and vitamin D.

65
Q

Chylomicron fxn

A

Delivers dietary TGs to peripheral tissues. Delivers cholesterol to liver in the form of chylomicron remnants, which are mostly depleted of their TGs. Secreted by intestinal epithelial cells.

66
Q

VLDL fxn

A

Delivers hepatic TGs to peripheral tissue. Secreted by liver.

67
Q

IDL fxn

A

Delivers TGs and cholesterol to liver. Formed from degradation of VLDL.

68
Q

LDL fxn

A

Delivers hepatic cholesterol to peripheral tissues. Formed by hepatic lipase modification of IDL in the liver and peripheral tissue. Taken up by target cells via receptor-mediated endocytosis. LDL is Lethal.

69
Q

HDL fxn

A

Mediates reverse cholesterol transport from periphery to liver. Acts as a repository for apolipoproteins C and E (which are needed for chylomicron and VLDL metabolism). Secreted
from both liver and intestine. Alcohol ^ synthesis. HDL is Healthy.

what the fuck it’s real

https://www.ncbi.nlm.nih.gov/pubmed/11067787

cheers!

70
Q

Abetalipoproteinemia

Inheritance, gene mutation, and what is absent + deficient

A

Autosomal recessive.

Mutation in (MTTP) gene that encodes microsomal transfer protein (MTP).
Chylomicrons, VLDL, LDL absent.

Deficiency in ApoB-48, ApoB-100.

71
Q

Abetalipoproteinemia Sx

A

Affected infants present
with severe fat malabsorption, steatorrhea, failure to thrive. Later manifestations include retinitis
pigmentosa, spinocerebellar degeneration due to vitamin E deficiency, progressive ataxia,
acanthocytosis. Intestinal biopsy shows lipid-laden enterocytes.

72
Q

Abetalipoproteinemia Tx

A

Treatment: restriction of long-chain fatty acids, large doses of oral vitamin E.

73
Q

AR familial dyslipidemias

A

Type I - Hyperchylomicronemia

Type III - Dysbetalipoproteinemia

74
Q

AD familial dyslipidemias

A

Type II - Familial Hypercholesterolemia

Type IV - Hypertriglyceridemia

75
Q

Familial dyslipidemias Type I—Hyperchylomicronemia pathogenesis

A

Lipoprotein lipase or
apolipoprotein C-II
deficiency

76
Q

Familial dyslipidemias Type I—Hyperchylomicronemia ^ blood level

A

Chylomicrons, TG,
cholesterol

77
Q

Familial dyslipidemias Type I—Hyperchylomicronemia clinical presentation

A

Pancreatitis,
hepatosplenomegaly, and
eruptive/pruritic xanthomas
(no inc risk for atherosclerosis).
Creamy layer in supernatant.

78
Q

Familial dyslipidemias Type II—Familial hypercholesterolemia

pathogenesis

A

Absent or defective
LDL receptors, or
defective ApoB-100

79
Q

Familial dyslipidemias Type II—Familial hypercholesterolemia

^ blood level

A

IIa: LDL, cholesterol
IIb: LDL, cholesterol,
VLDL

80
Q

Familial dyslipidemias Type II—Familial hypercholesterolemia

clinical presentation

A

Heterozygotes (1:500) have
cholesterol ≈ 300mg/dL;
homozygotes (very rare) have
cholesterol ≈ 700+ mg/dL.
Accelerated atherosclerosis (may
have MI before age 20), tendon
(Achilles) xanthomas, and
corneal arcus.

81
Q

Familial dyslipidemias Type III—Dysbetalipoproteinemia

pathogenesis

A

Defective ApoE

82
Q

Familial dyslipidemias Type III—Dysbetalipoproteinemia

^ blood level

A

Chylomicrons, VLDL

83
Q

Familial dyslipidemias Type III—Dysbetalipoproteinemia

clinical presentation

A

Premature atherosclerosis,
tuberoeruptive and palmar
xanthomas.

84
Q

Familial dyslipidemias Type IV—Hypertriglyceridemia

pathogenesis

A

Hepatic overproduction of VLDL

85
Q

Familial dyslipidemias Type IV—Hypertriglyceridemia

^ blood level

A

VLDL, TG

86
Q

Familial dyslipidemias Type IV—Hypertriglyceridemia

Clinical presentation

A

Hypertriglyceridemia (> 1000 mg/dL) can cause acute
pancreatitis. Related to insulin resistance.

Step 1 2019 First Aid Flashcards (63 decks)

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