Biochem Flashcards
1
Q
Glycogen storage diseases
Very Poor Carbohydrate Metabolism
A
Von Gierke (type I) Pompe (type II) Cori disease (type III) McArdle disease (type V)
2
Q
What is it? Other findings?
Severe fasting hypoglycemia
Increased glycogen in liver
A
Von Gierke Disease
Increased blood lactate, increased TGs, increased uric acid, hepatomegaly, enlarged kidneys
3
Q
Glucose 6 Phosphatase is deficient
A
Von Gierke Disease
can’t make glucose 6 phosphate into glucose
4
Q
Treatment of Von Gierke Disease
A
Glucose 6 Phosphatase deficiency treated with frequent oral glucose/cornstarch and avoidance of fructose and galactose
5
Q
Deficiency of Pompe disease
A
Lysosomal a-1,4-glucosidase (acid maltase) (degrades glyocogen in lysosomes)
6
Q
Cardiomegaly, hypertrophic cardiomyopathy, exercise intolerance, diaphragm weakness
A
Pompe disease
7
Q
What is the inheritance of glycogen storage diseases (Very Poor Carbohydrate Metabolism)?
A
Autosomal Recessive
8
Q
Milder form of Von Gierke disease with normal blood lactate levels
A
Cori disease (debranching enzyme a-1-6-glucosidase)
9
Q
Increased glycogen in muscle but it cannot break down
A
McArdle disease
10
Q
Findings in McArdle disease
A
Painful muscle cramps, myoglobinuria (red urine) with strenuous exercise and arrhythmia from electrolyte abnormalities
11
Q
Enzyme deficiency in McArdle disease
A
Skeletal muscle glycogen phosphorylase (myophosphorylase) (liberates glucose 1 phosphate residues)
12
Q
Other findings of Cori cycle
A
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
Q
Accumulation of short dextrin like structures in cytosol of hepatocytes
A
Cori disease
14
Q
Which body tissues are deficient in sorbitol dehydrogenase?
A
Retina
Renal papilla
Schwann cells
15
Q
Peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal disease, corneal opacities, pain, HTN
A
Fabry disease (lysosomal storage disease) X linked Recessive
16
Q
Deficiency in Fabry disease
What accumulates?
A
Alpha-galactosidase A is deficient
Ceramide trihexoside accumulates
17
Q
Most common lysosomal storage disorder
A
Gaucher disease (glucocerebrosidase; B-glucosidase deficiency)
18
Q
Lipid laden macrophages resembling crumpled tissue paper
A
Gaucher cells seen in Gaucher disease (lysosomal storage disorder)
19
Q
Lysosomal storage disorder with severe bone pain
A
Gaucher disease - aseptic necrosis of femur, bone crises, osteoporosis
20
Q
X linked recessive lysosomal storage disorder
A
Fabry disease - alpha galactosidase A deficiency
21
Q
Progressive neurodegeneration, HEPATOSPLENOMEGALY, foam cells, CHERRY RED spot on macula
A
Niemann-Pick Disease
Foam cells are lipid laden macrophages
22
Q
Sphingomyelinase deficiency
What accumulates?
A
Niemann Pick Disease
Sphingomyelin accumulates
23
Q
Progressive neurodegeneration, developmental delay, CHERRY RED spot on macula, lysosomes with ONION skin, NO hepatosplenomegaly
A
Tay Sachs disease (deficiency in hexosaminidase A)
24
Q
What accumulates in Tay Sachs?
A
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
```
