Biochem Flashcards
(93 cards)
1
Q
Purines
A
A, G, 2 rings, easier to make
2
Q
Pyrimidines
A
C, T, U, 1 ring, harder to make
3
Q
Amino acids necessary for purine synthesis
A
GAG, Glitter and Glue (Glycine, Aspartate, Glutamine)
4
Q
Drugs blocking purine synthesis
A
MMF, Ribavirin (IMP dehydrogenase)
HU (ribonucleotide reductase)
6-MP, azathioprine (de novo purine synthesis)
5
Q
Drugs blocking pyrimidine synthesis
A
Leflunomide (dihydroorage dehydrogenase)
HU (ribonucleotide reductase)
5-FU (thymidylate synthase)
MTX, tMP, pyrimethamine (DHFR in human, bacteria, protozoa, respectively)
6
Q
Transition
A
Purine to purine or pyrimidine t pyrimidine (moving down the street)
7
Q
Transversion
A
Purine to pyrimidine or vice versa (crossing the street)
8
Q
N-oligosaccharides
A
asparagine
9
Q
O-oligosaccharides
A
Serine, threonine
10
Q
M6P
A
Proteins going to the lysosome
11
Q
Type 1 Cartilage
A
Bone
Skin
Tendon
12
Q
Type 2 Cartilage
A
Hyaline cartilage
Vitreous Body
Nucleus pulposus
13
Q
Type 3 Cartilage
A
Reticulin (skin blood vessels, uterus, fetal tissue, granulation tissue)
14
Q
Type 4 Cartilage
A
Basement membrane, basal lamina, lens
15
Q
Heterodisomy
A
2 copies of chromosome from one parent due to meiosis I error, none from other parent
16
Q
Isodisomy
A
2 copies of chromosome fron one parent due to meiosis II or postzygotic duplication, none from other parent
17
Q
ADPKD
A
AD, PKD1 and 2, cystic kidneys, sometimes liver and pancreas
18
Q
Familial Adenomatous Polyposus
A
APC gene, adenomatous polyps, progress to cancer unless resect colon
19
Q
Familial Hypercholesterolemia
A
AD, LDL-receptor gene, severe atherosclerosis, xanthomas
20
Q
HHT
A
AD, disorder of blood vessels, telangiectasias, epistaxis, skin discoloration, AVM, GI bleeds, hematuria
21
Q
Hereditary spherocytosis
A
AD, spectrin or ankyrin gene, spheroid erythrocytes resulting in hemolytic anemia, increased MCHC, RDW
22
Q
Huntington
A
AD, trinucleotide repeat disease CAG in huntingtin gene, chorea, dementia, caudate atrophy, depression, increased DA, decreased GABA, ACh
23
Q
Li Fraumeni Syndrome
A
AD, P53 Gene, multiple malignancies
24
Q
Marfan syndrome
A
AD, fibrillin gene, CTD affecting skeleton, heart, eyes, tall, long extremities, pectus excavatum, hypermobile joints, arachnodactyly, cystic medial necrosis of aorta –> aortic incompetence and dissecting aneurysms, floppy mitral valve, subluxation of lenses
25
MEN
AD, MEN1: MEN1 gene, MEN2: RET gene, multiple endocrine neoplasias
26
NF
AD
NF1: NF1 gene, chr17, CALM, neurofibroma, optic glioma, pheochromocytoma, lisch nodule
NF2: NF2 gene, chr22, schwannomas, meningomas, ependymomas
27
TSC
TSC1 and 2 benign hamartomas
28
VHL
VHL gene, chr3, numerous tumors,
29
Serology findings for trisomy 21
First trimester:
- serum PAPPa down
- free beta-HCG up,
- increased nuchal translucency
Second trimester:
- alpha-fetoprotein and estriol down
- free beta-HCG and inhibin A up
30
Serology findings for trisomy 18
First trimester:
- PAPPa and beta-HCG down
Second trimester:
- alpha-fetoprotein, beta-HCG, estriol and inhibin A down (or normal inhibin A)
31
Serology findings for trisomy 13
First trimester:
| - free betaHCG and PAPPa down, increased nuchal translucency
32
Vitamin A deficiency
```
night blindness
dry scaly skin
corneal degeneration
bitot spots on conjunctiva
immunosuppression
```
33
Vitamin A excess
Retinol
```
Acute:
N&V
vertigo
blurred vision
Chronic:
alopecia
dry skin
hepatic toxicity and enlargement
arthralgias
psurdotumor cerebri
```
34
Vitamin B1 deficiency
Adult-acquired: Wernicke-Korsakoff
Thiamine
```
confusion and memory loss
opthalmoplegia
ataxia
nystagmus
confabulation and personality change
```
Childhood-acquired:
Dry beriberi: polyneuritis, muscle wasting
Wet beriberi: high-throughput cardiac failure (DCM), edema
35
Vitamin B2 deficiency
Riboflavin
cheilosis
corneal vacularization
36
Vitamin B3 deficiency
Niacin (derived from tryptophan)
Glossitis
Pellagra (diarrhea, dementia/hallucinations, dermatitis)
37
Vitamin B3 excess
Niacin (derived from tryptophan), lowers VLDL, raises HDL
Facial flushing (PG-mediated, avoid w/aspirin)
Hyperglycemia
Hyperuricemia
38
Vitamin B5 deficiency
Pantothenic acid
dermatitis
enteritis
alopecia
adrenal insufficiency
39
Vitamin B6 deficiency
Pyridoxine
convulsions
hyperirritability
peripheral neuropathy (esp w/isoniazid and OCP tx)
sideroblastic anemia
40
Vitamin A
```
visual pigments
epithelial differentiation
block squamous metaplasia
tx measles, AML3
liver and leafy veggies
```
41
Vitamin B1
alpha ketoglutarage dehydrogenase
transketolase (HMP shunt)
pyruvate dehydrogenase
branced chain ketoacid dehydrogenase
42
Vitamin B2
component of flavins FAD and FMN, used in TCA cycle
43
Vitamin B3
component of NAD, NADP used in redox reactions
| require b2 and b6 for sx
44
Vitamin B5
essential component of coenzyme A (CoA) and FA synthase
45
Vitamine B6
```
converted to pyridoxal phosphate, used for:
transamination
decarboxylation
glycogen phosphorylase
Sx of:
heme
niacin
histamine
NT's (Serotonin, Epi, NE, Da, GABA)
```
46
Vitamin B7
cofactor for carboxylation enzymes (which add 1 carbon at a time)
47
Vitamin B7 deficiency
Biotin (caused by abx use or egg white ingestion)
Dermatitis
Alopecia
enteritis
48
Vitamin B6
Converted to tetrahydrofolic acid
coenzyme for 1-carbon transfer/methylation
synthesis of nitrogenous bases in DNA and RNA
leafy green vegetables
absorbed in jejunum
reservoir in liver
49
Vitamin B6 deficiency
Folate (deficiency in alcohol, pregnancy, phenytoin, sulfonamide, mtx use)
Macrocytic, megaloblastic anemia
hypersegmented PMN's
glossitis
neural tube defects in pregnancy
Labs:
incr. homocysteine
nl. MMA
50
Vitamin B12
cofactor for
- homocysteine methyltransferase (make methionine from homocysteine)
- methylmalonyl-CoA mutase (part of heme production pathway from FA, branched chain aa's)
found in animal products
synthesized only by microorganisms
large reservoir pool in liver
51
Vitamin B12 Deficiency
Cobalamin (Deficiency caused by insufficient intake, malabsorption, lack of IF, gastric bypass, absence of terminal ileum, tapeworm, anti-IF antibody)
```
Macrocytic, megaloblastic anemia
hypersegmented PMN's
paresthesias
subacute combined degeneration (demyelination of dorsal column, lateral corticospinal tracts, and spinocerebellar tracts resulting in:
- large fiber sensory polyneuropathy
- nerupsych. symptms
- optic neuropathy)
```
Labs:
incr. homocysteine AND mma
52
Vitamin C
antioxidant
facilitates iron absorption by reducing to Fe2+ state
necessary for hydroxylation of proline and lysine in collagen synthesis
necessary for conversion of DA to NE (dopamine beta hydroxylase)
found in fruits and veggies
tx for methemoglobinemia by reducing iron
53
Vitamin C deficiency
Ascorbic Acid
Scurvy (collagen synth. defect)
- swollen gums
- buising
- petechiae
- hemarthrosis
- anemia
- poor wound healing
- perifollicular and subperiosteal hemorrhage
- corkscrew hair
- weakened immune system
54
Vitamin C excess
```
N&V
diarrhea
fatigue
calcium oxalate nephrolithiasis
increased risk of iron tox in predisposed people
```
55
Vitamin D
Ergocalciferol from plants, cholecalciferol from milk, made in skin
converted to calcitriol (1,25-OH-D)
increases intestinal absorption of phosphate and calcium
increases bone mineralization
Breasfeeding: give supplemental oral vitamin D to baby
56
Vitamin D deficiency
- Deficiency in breastfed children, low sun exposure, pigmented skin, prematurity
Rickets in children (bone pain with deformity)
Osteomalacia in adults (bone pain with muscle weakness)
Hypocalcemic tetany
57
Vitamin D excess
Hypercalcemia, hypercalciuria
Loss of appetite
Stupor
Sometimes seen in granulomatous disease due to activation by epithelioid macrophages
58
Vitamin E
Antioxidant that protects RBCs and membranes from free radical damage
Enhances anticoagulation effects of warfarin
59
Vitamin E deficiency
Tocopherol/Tocotrienol
Hemolytic anemia
Acanthocytosis
Muscle weakness
Posterior column and spinocerebellar tract demyelination (similar to B12 deficiency w/o megaloblastic anemia and hypersegmented PMNs, or increased MMA)
60
Vitamin K
```
Cofactor for gamma-carboxylation of glutamic acid on proteins needed for clotting (Factors 2, 7, 9, 10, protein C and protein S)
Synthesized by intestinal flora
Note:
- neonates have sterile intestines
- not in breast ilk
- abx tx will destroy flora
```
61
Vitamin K deficiency
Neonatal hemorrhage with increased PT and PTT (nl bleeding time)
62
Zinc
essential for enzyme activity, transcription factors
63
Zinc deficiency
```
Delayed wound healing
Hypogonadism
Decreased adult hair
Dysgeusia
Anosmia
Acrodermatits enteropathic
```
Alcoholic cirrhosis predisposition
64
Kwarsiorkor
Protein malnutrition
- skin lesions
- edema
- liver malfunction (fatty change)
- anemia
65
Marasmus
Total calorie malnutrition:
- tissue and muscle wasting
- loss of subQ fat
- variable edema
66
Arsenic
- causes glycolysis to produce zero net ATP
- inhibits lipoic acid (cofactor for pyruvate dehydrogenase complex)
- Produces: vomiting, rice-water stools, gralic breath
67
Pyruvate dehydrogenase complex deficiency
- pyruvate buildup because cannot be used in TCA cycle
- pyruvate shunted to lactate and alanine
- X-linked (or due to nutritional deficiency of cofactors)
- see neurologic defects, lactic acidosis, increased serum alanine
- if X-linked: increase intake of ketogenic nutrients leucine and lysine (the only purely ketogenic aa's)
68
Rate-limiting step of glyolysis
phosphofructokinase (fructose 6-phosphate to fructose 1,6-bisphosphate)
69
Rate-limiting step of gluconeogenesis
fructose 1,6 bisphosphatase (f 1,6 BP to F6P)
70
Rate-limiting step of TCA cycle
isocitrate dehydrogenase (isocitrate to alpha ketoglutarate)
71
Rate-limiting step of glycogenesis
glycogen synthase
72
Ketogenic aa's
Leucine and lysine
73
Essential aa's
LiL HuMVee PITT:
- LiL = Leucine, lysine, ketogenic
- HMV = His, Met, Val, glucogenic
- PIT = Phe, Ile, Thr, Trp, gluco/ketogenic
74
Pyruvate dehydrogenase deficinecy
- can't use pyruvate in TCA
- X-linked
- lactic acidosis, neruo. defects, high serum alanine
- consume ketogenic compounds (fat, leucine, lysine)
75
N-acetylglutamate synthase deficiency
- cannot use carbamoyl phosphate syntase 1 deficiency to allow NH3 to enter urea cycle.
- accumulate ammonia
- neonates: poorly regulated body temp, respiration, poor feeding, developmental delay and ID
76
Ornithine transcarbamylase deficiency
- most common
- X-linked recessive
- interferes with ammonia elimination
- increased orotic acid due to shunting of excess carbamoyl phosphate
- decreased BUN
- symptoms of hyperammonemia
- NO megaloblastic anemia
77
PKU
- deficiency of Phenylalanine Hydroxylase OR Tetrahydrobipterin Cofactor
- Autosomal recessive
- ID, growth retard, seizure, fair skin, musty body odor
- Maternal: neonate with ID, microcephaly, growth retard. heart defects
78
Maple Syrup Urine
- deficiency of Alpha-ketoacid dehydrogenase
- degradation of branched amino acids is blocked (leucine, isoleucine, valine)
- CNS defects, ID, death
- urine smelling like burnt sugar, increased alpha ketoacids in blood, esp from leucine
79
Alkaptonuria
- deficiency of homogentisate oxidase
- cannot degrade tyrosine to fumarate
- accumulate pigment-formine homogentisic acid in tissues
- dark connective tissue, brown pigmented sclerae, urine turns black when exposed to air,
- arthralgias possible
80
Homocystinuria
3 types, all autosomal recessive
- deficiency or decreased B6 affinity of cystathione synthase (makes cysteine)
- deficiency of homocysteine methyltransferase (makes methionine)
- all have excess urinary homocysteine, ID, osteoporosis, marfanoid habitus, kyphosis, lens subluxation (down and in), thrombosis, atherosclerosis
81
Cystinuria
- amino acid transporter (PT and intestine)
- inability to reabsorb COAL (cysteine, ornithine, arginine, lysine)
- hexagonal cystine stones
- alkalinize urine, hydrate, chelation,
- dx w/CN nitroprusside urinary test
82
Von Gierke Disease
- Defect in G6 phosphatase
- cannot release glucose from liver cells
- hepatomegaly, high glycogen in liver, lactic acidosis, increased uric acid, increased tg's
83
Pompe disease
- defect in alpha 1,4 glucosidase (alternative enzyme for degrading glycogen in lysosome)
- cardiomegaly, hypertrophic cardiomyopathy, floppy baby, early death
84
Cori disease
- debranching enzyme (alpha 1,6 glucosidase) deficiency
| - mild disease with normal blood lactate
85
McArdle Disease
- deficiency of muscle glycogen phosphorylase
- muscles cannot release glucose from glycogen
- increased muscle glycogen, muscle cramps, myoglobinuria w/exercise, arrhythmia from electrolyte abnormalities, normal blood glucose
- tx with B6 (cofactor)
86
Fabry
Deficiency: Alpha galactosidase A (XR)
Buildup: Ceramide trihexidose
Sx: acroparesthesia, hypohidrosis, angiokeratoma, CV/Renal/GI complications, corneal opacity
87
Gaucher
Deficiency: Glucocerebrosidase (AR)
Buildup: Glucocerebroside
Sx: HSM, erlenmyer flask bones, pancytopenia, osteoporosis, aseptic necrosis of femur, gaucher cells
88
Niemann-Pick
Deficiency: Sphingomyelinase (AR)
Buildup: sphingomyelin
Sx: progressive neurodegeneration, HSM, foam cells, cherry red spot, ILD/recurrent lung infection
89
Tay-Sachs
Deficiency: Hexosaminidase A (AR)
Buildup: GM2 ganglioside
Sx: progressive neurodegeneration, foam cells, cherrry red spot, lysosomes with onion skin
90
Krabbe
Deficiency: Galactocerebrosidase (AR)
Buildup: galactocerebroside, psychosine
Sx: peripheral neuropathy, developmental delay, optic atrophy, globoid cells
91
Metachromatic Leukodystrophy
Deficiency: Arylsulfatase A (AR)
Buildup: cerebroside sulfate
Sx: central and peripheral demyelination with ataxia, dementia
92
Hurler
Deficiency: Alpha-L-Iduronidase (AR)
Buildup: heparan sulfate, dermatan sulfate
Sx: developmental delay, gargoylism, airway obstruction, corneal clouding, HSM
93
Hunter
Deficiency: Iduronate sulfatase (XR)
Buildup: heparan sulfate, dermatan sulfate
Sx: mild hurler + aggressive behavior, no corneal clouding
