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Flashcards in Biochem Deck (104):
1

Glycogen storage diseases
(Very Poor Carbohydrate Metabolism)

Von Gierke (type I)
Pompe (type II)
Cori disease (type III)
McArdle disease (type V)

2

What is it? Other findings?
Severe fasting hypoglycemia
Increased glycogen in liver

Von Gierke Disease
(Increased blood lactate, increased TGs, increased uric acid, hepatomegaly, enlarged kidneys)

3

Glucose 6 Phosphatase is deficient

Von Gierke Disease
(can't make glucose 6 phosphate into glucose)

4

Treatment of Von Gierke Disease

Glucose 6 Phosphatase deficiency treated with frequent oral glucose/cornstarch and avoidance of fructose and galactose

5

Deficiency of Pompe disease

Lysosomal a-1,4-glucosidase (acid maltase) (degrades glyocogen in lysosomes)

6

Cardiomegaly, hypertrophic cardiomyopathy, exercise intolerance, diaphragm weakness

Pompe disease

7

What is the inheritance of glycogen storage diseases (Very Poor Carbohydrate Metabolism)?

Autosomal Recessive

8

Milder form of Von Gierke disease with normal blood lactate levels

Cori disease (debranching enzyme a-1-6-glucosidase)

9

Increased glycogen in muscle but it cannot break down

McArdle disease

10

Findings in McArdle disease

Painful muscle cramps, myoglobinuria (red urine) with strenuous exercise and arrhythmia from electrolyte abnormalities

11

Enzyme deficiency in McArdle disease

Skeletal muscle glycogen phosphorylase (myophosphorylase) (liberates glucose 1 phosphate residues)

12

Other findings of Cori cycle

Hypoglycemia, hyperTG, ketoacidosis, hepatomegaly, ACCUMULATION of SHORT DEXTRIN like structures in cytosol of hepatocytes, no fatty infiltration of liver
NORMAL kidneys, lactate and uric acid

13

Accumulation of short dextrin like structures in cytosol of hepatocytes

Cori disease

14

Which body tissues are deficient in sorbitol dehydrogenase?

Retina
Renal papilla
Schwann cells

15

Peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal disease, corneal opacities, pain, HTN

Fabry disease (lysosomal storage disease)
X linked Recessive

16

Deficiency in Fabry disease
What accumulates?

Alpha-galactosidase A is deficient
Ceramide trihexoside accumulates

17

Most common lysosomal storage disorder

Gaucher disease (glucocerebrosidase; B-glucosidase deficiency)

18

Lipid laden macrophages resembling crumpled tissue paper

Gaucher cells seen in Gaucher disease (lysosomal storage disorder)

19

Lysosomal storage disorder with severe bone pain

Gaucher disease - aseptic necrosis of femur, bone crises, osteoporosis

20

X linked recessive lysosomal storage disorder

Fabry disease - alpha galactosidase A deficiency

21

Progressive neurodegeneration, HEPATOSPLENOMEGALY, foam cells, CHERRY RED spot on macula

Niemann-Pick Disease
Foam cells are lipid laden macrophages

22

Sphingomyelinase deficiency
What accumulates?

Niemann Pick Disease
Sphingomyelin accumulates

23

Progressive neurodegeneration, developmental delay, CHERRY RED spot on macula, lysosomes with ONION skin, NO hepatosplenomegaly

Tay Sachs disease (deficiency in hexosaminidase A)

24

What accumulates in Tay Sachs?

GM2 ganglioside

25

Sphingolipidoses with optic atrophy

Krabbe disease (Galactocerebrosidase deficiency)

26

Galactocerebrosidase deficiency

Krabbe disease

27

Metachromatic leukodystrophy deficiency

Arylsulfatase A

28

CENTRAL and peripheral demyelination with ataxia, dementia

Metachromatic leukodystrophy (arylsulfatase A deficiency)

29

Developmental delay, gargoylism, airway obstruction, corneal clouding (vision loss), hepatosplenomegaly

Hurler syndrome - alpha-L-iduronidase deficiency

30

Mild Hurler + aggressive behavior; NO corneal clouding

Hunter syndrome (iduronate sulfatase deficiency)

31

Inheritance of Hurler and Hunter syndrome

Hurler - Autosomal recessive
Hunter - X linked recessive

32

How do you differentiate between Cori disease and Von Gierke disease?

Von Gierke - has enlarged kidneys, with increased lactate and uric acid
Cori disease - normal kidneys, lactate and uric acid
Both have hypoglycemia, increased TGs, hepatomegaly

33

No man picks his nose with his sphinger

Niemann-Pick - sphingomyelinase deficiency

34

Tay Sach deficiency

HeXoasaminidase

35

Hunter vs. Hurler

Hunter's see clearly (NO corneal clouding)
Hunter's is X linked recessive

36

When is non-homologous end joining mutated?

Ataxia telangiectasia
Fanconi anemia
(Non-homologous end joining brings together 2 ends of DNA fragments to repair ds breaks)

37

Direction of DNA and RNA synthesis?
Direction of protein synthesis?

Both DNA and RNA are synthesized 5' to 3'; mRNA is read 5' to 3'
Protein synthesis is N terminus to C terminus

38

Drugs blocking DNA replication have modified what? Why?

Modified 3' OH preventing addition of the next nucleotide because the triphosphate bond is the target of the 3' hydroxyl attack - the 5' end of the incoming nucleotide bears the triphosphate (energy source for bond)

39

What is fMet? What does it stimulate?

fMet is N-formylmethioine; this is what AUG start codon codes for in prokaryotes
fMet stimulates neutrophil chemotaxis

40

Effects of alpha amanitin

Inhibits RNA polymerase II (responsible for making mRNA) and causes severe hepatotoxicity
(Found in death cap mushrooms)

41

Where does RNA processing occur?

hnRNA becomes mRNA via capping, polyadenylation and splicing in the NUCLEUS
mRNA quality control occurs at P-bodies in the CYTOPLASM (contains exonuclease, decapping enzymes, microRNAs; they can be stored here for future translation)

42

Anti-spliceosomal snRNPs (anti-Smith Antibodies)

Highly specific for SLE

43

Which amino acids are required during periods of growth?

Arginine and Histidine

44

Essential amino acids (PVT TIM HaLL)

Phenylalanine
Valine
Threonine
Tryptophan
Isoleucine
Methionine
Histidine
Leucine
Lysine

45

Reduced renal tubular reabsorption of tryptophan

Hartnup disease --> causes pellagra symptoms (dermatitis, dementia, diarrhea)

46

Symptoms of Methemoglobinemia

headache, dizziness, nausea, shortness of breath, confusion, seizures, and coma
-Blood may have a characteristic muddy color secondary to the oxidization state of iron

47

Clinical hallmarks of NF 1

Cafe au lait spots
Neurofibromas
Lisch nodules (pigmented iris hamartomas)
Skeletal abnormalities are common - scoliosis or vertebral defects or long bone dysplasia

48

Which types of cells are most affected by chemotherapy?

Labile tissues that never got to G0 and divide rapidly with a short G1 phase --> bone marrow, gut epithelium, skin, hair follicles, germ cells

49

How does golgi apparatus modify asparagine, serine and threonine?

Modifies N-oligosaccharides on asparagine
Modifies O oligosaccharides on serine/threonine

50

What is I-cell disease?

Failure of Golgi to phosphorylate mannose residues (decreased mannose-6-phosphate) on glycoproteins so that proteins get secreted extracellularly instead of going to the lysosomes
Defect in N-acetylglucosaminyl-1-phsophotransferase
Coarse facial features, clouded corneas, restricted joint movement

51

Coarse facial features, clouded corneas, restricted joint movement

I-cell disease (fatal in childhood) - Golgi can't phosphorylate mannose residues on glycoproteins = defective trafficking to lysosomes

52

Function and examples of each:
a. Microfilaments
b. Intermediate filaments
c. Microtubules

a. Muscle contraction, cytokinesis; actin
b. Maintain cell structure; vimentin, design, cytokeratin, lamina, GFAP, neurofilaments
c. Movement, cell division; cilia, flagella, mitotic spindle, axonal trafficking, centrioles

53

Which molecular motor proteins are responsible for which transport?

Dynein - retrograde to microtubule (+ --> - )
Kinesin - anterograde to microtubule ( - --> + )

54

Structure of cilia

9 + 2 arrangement of microtubule doublets
Coordinated contraction via gap junctions
Axonemal dynein - ATPase that links peripheral 9 doublets and causes bending of cilium by sliding of doublets

55

What is Menkes disease?

X linked recessive CT disease caused by impaired copper absorption and transport --> decreased activity of lysol oxidase (copper is necessary cofactor) --> brittle, kinky hair, growth retardation, hypotonia

56

What is responsible for cross linking step of collagen?

Tropocollagen molecules are cross linked by copper containing lysyl oxidase

57

Characteristics of osteogenesis imperfecta

Multiple fractures
Blue sclera - from translucency of CT over choroidal veins
Hearing loss
Dental imperfections due to lack of dentin

58

Types of Ehlers-Danlos and collagen type they affect

Classical type (joint and skin) --> mutation in type V collagen
Vascular type (vascular, organ rupture) --> deficient type III collagen

59

Where is elastin located?

Skin, lungs, large arteries, elastic ligaments, vocal cords, ligamenta flava

60

Difference between glycine, proline and lysine residues in Collagen and Elastin

Collagen - hydroxylated
Elastin - NONhydroxylated

61

What gives elastin it's elastic properties?

Cross linking between 4 different lysine residues

62

Quad screen in Down syndrome

Decreased alpha fetoprotein
Increased b-hCG
Decreased estriol
Increased inhibin A

63

Quad screen in Edwards (trisomy 18)

Decreased alpha fetoprotein
DECREASED bhCG
Decreased estriol
DECREASED or normal inhibin A

64

Quad screen in Patau syndrome (13)

Quad screen not helpful
Decreased free bhCG
Decreased PAPP-A
Increased nuchal translucency

65

Chromosome 15 disorders

Prader willi, Angelman

66

Chromsome 13 disorders

Patau syndrome, Wilson disease

67

Chromosome 11 disorders

Wilms tumor

68

Chromosome 9 disorders

Freidreich ataxia

69

Chromosome 7 disorders

Williams syndrome, CF

70

Chromosome 5 disorders

Cri-du-chat syndrome, Familial adenomatous polyposis

71

Chromosome 4 disorders

ADPKD with PKD2 defect,t Huntingtons

72

Chromosome 3 disorders

Von Hippel Lindau disease, Renal cell carcinoma

73

Chromosome 16 disorders

ADPKD with PKD1 defect

74

What is Cri du chat syndrome?

Congenital micro deletion of short arm of chromosome 5
Microcephaly, moderate to severe ID, high pitched mewing, epitcanthal folds, cardiac abnormalities

75

What is Williams syndrome?

Congenital micro deletion of short arm of chromosome 7; distinctive elfin facies, ID, hypercalcemia (from increased sensitivity to vitamin D), well developed verbal skills, extreme friendliness with strangers, cardiovascular problems

76

Which metabolic pathways occur in BOTH cytoplasm and mitochondria? (HUGs take 2)

Heme synthesis
Urea cycle
Gluconeogenesis

77

Where do these pathways take place?
a. Fatty acid oxidation
b. Glycolysis
c. Fatty acid synthesis
d. Acetyl coA production
e. HMP shunt
f. Protein synthesis
g. TCA cycle
h. Oxidative phosphorylation
i. Ketogenesis
j. Steroid synthesis
k. Cholesterol synthesis

a. fatty acid oxidation - mitochondria
b. glycolysis - cytoplasm
c. fatty acid synthesis - cytoplasm
d. acetyl coA production - mitochondria
e. HMP shunt - cytoplasm
f. protein synthesis - cytoplasm (RER)
g. TCA cycle - mitochondria
h. oxidative phosphorylation - mitochondria
i. ketogenesis - mitochondria
j. steroid synthesis - cytoplasm (SER)
k. cholesterol synthesis - cytoplasm

78

a. Rate determining enzyme of Glycolysis
b. Regulators

a. Phosphofructokinase 1 (PFK1)
b. Stimulated by AMP, fructose 2,6 bisphosphate; inhibited by ATP, citrate

79

a. Rate determining enzyme of Gluconeogenesis
b. Regulators

a. Fructose 1,6 bisphosphatase
b. Stimulated by ATP, acetyl coA; inhibited by AMP, fructose 2,6 bisphosphate

80

a. Rate determining enzyme of TCA cycle
b. Regulators

a. Isocitrate dehydrogenase
b. Stimulated by ADP, inhibited by ADP, NADH

81

a. Rate determining enzyme of Glycogenesis
b. Regulators

a. Glycogen synthase
b. Stimulated by glucose-6-phosphate, insulin and cortisol; inhibited by epinephrine, glucagon

82

a. Rate determining enzyme of Glycogenolysis
b. Regulators

a. Glycogen phosphorylase
b. Stimulated by glucagon, epinephrine, AMP; inhibited by insulin, glucose-6-phosphate, ATP

83

a. Rate determining enzyme of HMP shunt
b. Regulators

a. Glucose 6 Phosphate Dehydrogenase
b. Stimulated by NADP+; inhibited by NADPH-

84

a. Rate determining enzyme of De novo pyrimidine synthesis
b. Regulators

a. Carbamoyl Phosphate Synthetase II
b. Stimulated by ATP, inhibited by UTP

85

a. Rate determining enzyme of de novo purine synthesis
b. Regulators

a. Glutamine-Phosphoribosylpyrophosphate (PRPP) amidotransferase
b. Inhibited by AMP, IMP and GMP

86

a. Rate determining enzyme of urea cycle
b. Regulators

a. Carbamoyl Phosphate Synthetase I
b. Stimulated by N-acetylglutamate

87

a. Rate determining enzyme of fatty acid synthesis
b. Regulators

a. Acetyl coA carboxylase
b. Stimulated by insulin, citrate; inhibited by glucagon, palmitoyl coA

88

a. Rate determining enzyme of fatty acid oxidation
b. Regulators

a. Carnitine acyltransferaes I
b. Inhibited by malonyl coA

89

a. Rate determining enzyme of Ketogenesis

HMG Co A synthase

90

a. Rate determining enzyme of Cholesterol synthesis
b. Regulators

a. HMG Co A reductase
b. Stimulated by insulin, thyroxine; inhibited by glucagon, cholesterol

91

How many ATP are produced per glucose via:
a. Malate-aspartate shuttle
b. glycerol-3-phosphate shuttle
c. anaerobic glycolysis
d. glycolysis with arsenic

a. 32 ATP
b. 30 ATP
c. 2 ATP
d. 0 ATP

92

Universal electron acceptors:
a. What is NAD+ used for?
b. What is NADPH used for?

a. catabolic processes to carry reducing equivalents away as NADH
b. anabolic processes as supply of reducing equivalents

93

a. NAD+ is generally used in which processes?
b. NADPD is used in which processes?
c. What reactions is NADPH used in?

a. Catabolic - carries reducing equivalents away as NADH
b. Anabolic - steroid and fatty acid synthesis as a supply of reducing equivalents
c. Anabolic processes, Respiratory burst, Cytochrome P450 system, Glutathione reductase

94

What is carried on the following molecules?
a. ATP
b. NADH, NADPH, FADH2
c. CoA, lipoamide
d. Biotin
e. Tetrahydrofolates
f. S-adenosylmethionine
g. TPP

a. Phosphoric groups
b. Electrons
c. Acyl groups
d. CO2
e. 1 carbon units
f. CH3 groups
g. Aldehydes

95

How does arsenic affect ATP production?

It causes glycolysis to produce zero net ATP
It inhibits lipoic acid which is a co-factor needed for pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase --> vomiting, rice water stools, garlic breath

96

Vomiting, rice water stools, garlic breath

Arsenic poisoning --> inhibits lipoic acid (needed for pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase)

97

Neurologic defects, Lactic acidosis, Increased serum alanine

Pyruvate dehydrogenase deficiency (can't make pyruvate into acetyl co-A --> gets shunted to lactate or alanine)

98

Treatment for pyruvate dehydrogenase deficiency

Increased intake of ketogenic nutrients (lysine and leucine)

99

Which co-factors are needed for the following enzymes?
a. Alanine aminotransferase (pyruvate --> alanine)
b. Pyruvate Carboxylase (pyruvate --> oxaloacetate)
c. Pyruvate dehydrogenase (pyruvate --> acetyl coA)
d. Lactate dehydrogenase (pyruvate --> lactate)

a. B6
b. Biotin - B7
c. B1, B2, B3, B5, Lipoid acid
d. B3

100

What does the TCA cycle produce?

3 NADH
1 FADH2
2 CO2
1 GTP
that all = 10 ATP/acetyl coA

101

How can odd chain fatty acids produce glucose?

They yield propionyl coA during metabolism which can enter the TCA cycle as succinyl coA and undergo gluconeogenesis
(Even chain fatty acids can't do this because they only produce acetyl coA equivalents)

102

Where does HMP shunt take place and in which tissues?

In the cytosol - no ATP needed or produced
In the lactating mammary glands, liver, adrenal cortex, and RBCs - sites of fatty acid or steroid synthesis

103

Infantile cataracts
Failure to track objects or develop social smile

Galactokinase deficiency
Galactitol accumulates (galactose --> galactitol by aldose reductase)

104

Presentation of galactose-1-phosphate uridyltransferase deficiency

Failure to thrive
Jaundice
Hepatomegaly
Infantile cataracts
Intellectual disability
Can cause E. coli sepsis