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Flashcards in Biochem Deck (371)
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1
Q

Error in Meiosis I vs Meiosis II–what will RFLP fragments look like in a child with down’s syndrome?

A

Meiosis I: Will have three different chromosomes in the child
Meiosis II: will have duplicates of one chromosome and then one more chromosome

2
Q

Symptoms of fragile X

A

Macroorchidism
Dysmorphic face
Cognitive impariment
Aggressiveness

3
Q

What is the defect in fragile X? And which gene does it appear on?

A

Trinucleotide repeat CGG

–Occurs on FMR-1 gene on the X chromosome

4
Q

Short broad finers and transverse palmar creases

A

Down’s syndrome

5
Q

Precursor of tyrosine

A

phenylalanine

6
Q

Precursor of catecholamines

A

tyrosine

7
Q

precursor or urea and nitric oxide

A

arginine

8
Q

Precursor of niacin

A

tryptophan

9
Q

Pellagra features

A

dermatitis, diarrhea, dementia

10
Q

Pellagra is a deficiency in

A

niacin

11
Q

asymp pt with high fructosuria

A

defective fructokinase

12
Q

How does pt with essential fructosuria metabolize fructose?

A

hexokinase converts it to fructose 6 phosphate when can then be converted to pyruvate through a number of steps

13
Q

hexokinase

A

converts glucose–>G6P

converts fructose–>F6P (pathway not significant in normal individuals)

14
Q

aldose reductase

A

converts glucose to sorbitol

15
Q

PFK 1

A

Converts F6P to F1,6BP

16
Q

FBP phosphatase-1

A

Converts F1,6BP to F6P

17
Q

fructokinase

A

Fructose–>Fructose1P

18
Q

Aldolase B

A

Fructose1P–>DHAP and glyceraldehyde

19
Q

Triokinase

A

Glyceraldehyde–>G3P

G3P can then be used to generate pyruvate

20
Q

Aldolase A (and B)

A

Combines G3P and DHAP to make F1,6BP

21
Q

Carbon tetrachloride

A

Damages through free radical CCl3

–degrades lipis and produces hydrogen peroxide

22
Q

how does huntington’s dz cause effects?

A

CAG repeats which causes hypermethylation of histones

23
Q

Tx: lead poisoning

A

dimercaprol/EDTA

24
Q

Rb gene regulates:

A

TUMOR suppressor that regulates G1-S transition

25
Q

Rb tumor?

A

retinoblastoma
osteosarcoma
breast/lung/colon

26
Q

Ras pathway

A

MAP kinase

27
Q

Ras tumor

A

follicular thyroid cancer

28
Q

Bcl2

A

follicular lymphoma

29
Q

Gm2 ganglioside accumulation

A

Tay Sachs

30
Q

heparan sulfate and dermatan sulfate accumulation

A

Deficiency in alpha-L iduronidase

31
Q

Deficiency in alpha L iduronidase

A

Hurler syndrome

32
Q

Glucocerebroside accumulation

A

Gaucher disease

33
Q

Deficiency of glucose 6 phosphatase

A

Von Gierke

34
Q

Deficiency of lysosomal alpha 1,4 glucosidase

A

Pompe disease

35
Q

Accumulation of ceramide trihexoside

A

alpha galactosidase A deficiency

Fabry disease

36
Q

angiokeratomas, acroparesthesia, hypohidrosis and renal failure

A

Fabry disease

37
Q

Deficiency of sphingomyelinase

A

Niemann pick

38
Q

Presentation of Niemann pick

A

Hepatosplenomegaly
hypotonia
cherry red macular spot

39
Q

Foamy histiocytes

A

foamy histiocytes

40
Q

Inheritance of niemann pick

A

autosomal recessive. Die by age 3

41
Q

microganthia, low set ears, rocker bottom feet. Over-riding fourth and fifth fingers

A

Edwards syndrome, trisomy 18. Usually fetal death

42
Q
cleft lip and palate
polydactyly
microcephaly
rocker bottom feet
umbilical hernia
A

Patau syndrome

Trisomy 13. Fetal death

43
Q

Which vitamin is used to make NAD/NADH?

A

niacin

44
Q

Four signs of niacin deficiency

A

dermatitis
dementia
diarrhea
death

45
Q

Which vitamin is essential for a transamination reaction?

A

B6 (pyradoxine)

Transaminases are necessary for synethesizing amino acids

46
Q

Thiamine is used in which enzymes

A

transketolase, alpha-ketoglutarate dehydrogenase, and pyruvate dehydrogenase

47
Q

Riboflavin is used for:

A

FMN and FAD dehydrogenase rxns

48
Q

Biotin is used for:

A

Carboxylases

  1. pyruvate carboxylase
  2. acetyl CoA carboxylase
  3. Propionyl CoA carboxylase
  4. 3-methylcrotonyl-CoA-carboxylase
49
Q

Pleiotropy

A

One gene has many effects

50
Q

Methotrexate inhibits

A

DHFR reductase. Results in a build up of DHF.

Blocks BOTH folid acid–>DHF AND DHF–>THF

51
Q

Folinic acid is also known as

A

leucovorin. A form of THF that can bypass DHFR in pts getting methotrexate

52
Q

5 FU

A

Inhibits thymidylate synthase which converts N5,N10 methylene THF back to DHF

53
Q

Pantothenic acid

A

Makes coenzyme A. Necessary for AcetylCoA in first step of TCA+oxaloacetate–>citrate

Also synthesis of vitamin AD, cholesterol, steroids, lots of stuff

54
Q

Sx of pantothenic acid deficiency

A

burning feet and GI distress

55
Q

DiGeorge=deletion on chromosome…

A

22

56
Q

Battery factories at risk for poisoning of:

A

lead. Also mining, chemical processing, radiator repair, recycling

57
Q

Sx of lead poisoning

A

GI distress
lead line on gum
peripheral neuropathy (wrist/ankle drop)

58
Q

Single palmar crease

A

Down’s syndrome

59
Q

Resistance to chemotherapeutic agents (broad range) comes from

A

MDR1 gene for P-glycoprotein, a ATP dependent efflux pump

60
Q

What does southwestern blot measure?

A

DNA-bound protein

61
Q

You need lipoic acid for…

A
Pyruvate dehydrogenase (lactic acidosis)
alphaketoglutarate dehydrogenase
branched-chain ketoacid DH (maple syrup urine disease)
62
Q

PDH co-enzymes

A

thiamine
lipoic acid
CoA, FAD, NAD_+
–>if absent, will build up lactate

63
Q

Reye’s syndrome

A

giving aspirin to children causes:

  1. Hepatic dysfunction. Microvesicular steatosis with high ALT, AST, ammonia, and bili
  2. Encephalopathy of Reye’s. Hyperammonemia causes cerebral edema and coma
64
Q

Osler-Weber-Rendu syndrome

A

telangiectasis in skin and mucosal membranes. Epistaxis, GI bleeding, hematuria result

65
Q

Inheritance of osler weber rendu

A

Autosomal dominant

66
Q

Which drugs inhibit DHFR?

A

Trimethoprim, methotrexate, and pyrimethamine

67
Q

Elongation factorsq

A

facilitate tRNA binding and translocation in protein synthesis

68
Q

How do you clinch the dx of riboflavin deficiency?

A

glutathione reducase assy

urinary riboflavin excretion

69
Q

action of riboflavin

A

Used to synthesize FMN and FAD, components of Complex I and II.

  • -Also, an electron carrier in TCA cycle
  • -Also a cofactor for succcinate dehydrogenase
70
Q

Explain the process of base excision repair

A
  1. glycosylase cleaves out wrong base pair match
  2. endonuclease cleaves 5’ end
  3. lyase cleaves 3’ sugar phosphate backbone
  4. DNA polymerase and ligase fill gaps
71
Q

Cystic fibrosis causes what protein level changes?

A

defective post translational folding and glycosylation. Thus CFTR is degraded before it reaches the surface

72
Q

leucovorin

A

N5-formyl THF does NOT need reduction by DHFR. Bypasses methotrexate block.

73
Q

How does leucovorin interact with 5-FU

A

potentiates effect. 5-FU works better in the presence of folate in order to complex with thymidylate synthetase.

74
Q

Trisomy 13 is caused by:

A

defect during maternal meiosis I

75
Q

Nondisjunction in meiosis I causes

A

An extra chromosome, with an extra allele

76
Q

Nondisjunction in meiosis II causes

A

An extrachromosome, with an extra IDENTICAL chromosome

77
Q

47,xxx

A

clinically silent. maybe less IQ

78
Q

47 xyy

A

phenotype=normal

tall, severe acne, some motor/language delays

79
Q

long term complication of Edwards syndrome

A

meckel’s and malrotation

80
Q

long term complication of patau

A

they usually die!

  • holoprosencephaly, NTD
  • PDA< ASD< VSD
  • PCKD
  • pyloric stnosis, omphalocele
81
Q

HOCM caused by

A

cardiac sarcomere protein defect in the beta-myosin gene

82
Q

HOCM inheritance

A

autosomal dominant

83
Q

Causes of genetic dilated cardiomyopathy

A

AD dystrophin/mitochondrial enzyme mutations

84
Q

Gallstones caused by

A

high cholesterol

low bile acids and low phosphatidylcholine

85
Q

During times o plenty, what is the rate limiting step of fatty acid synthesis?

A

Acyl-CoA carboxylase

86
Q

Glucose 6 phosphatase

A

Produces free glucose form glucose 6 phosphate

87
Q

which enzyme catalyzes the first step in the beta oxidation pathway?

A

acyl CoA dehydrogenase

88
Q

melting temperature of DNA depends on

A

GC content (3 hydrogen bonds)

89
Q

hydroxyurea inhibits

A

ribonucleotide reductase

–UDP to dUDP

90
Q

Ornithine transcarbamoylase deficiency leads to an accumulation of

A

carbamoyl phosphate–>orotic acid

91
Q

6 mercaptopurine

A

Blocks purine synthesis

PRPP–>IMG

92
Q

5 FU

A

inhibits thymidylate synthase

–lack of dTMP

93
Q

methotrexate

A

blocks DHFR

–Converts DHF to THF needed for thymidylate synthase

94
Q

trimethoprim

A

inhibits bacterial DHFR

95
Q

Orotic aciduria

A

Inability to convert orotic acid to UMP

–Defect in UMP synthase

96
Q

inheritance of orotic aciduria

A

autosomal recessive

97
Q

Increase in orotic acid in urine, megaloblastic anemia that does NOT improve with B12, failure to thrive, No hyperammonia

A

orotic aciduria

98
Q

Treatment of orotic aciduria

A

oral uridine administration

99
Q

Aldolase B

A

Converts Fructose 1 P to DHAP and glyceraldehyde

100
Q

which codons are NOT degenerate?

A

methionine and tryptophan

101
Q

xanthine oxidase

A

Converts hypoxanthine–>xanthine
then
xanthine–>uric acid

102
Q

adenosine deaminase converts

A

adenosine to inosine–>hypoxanthine

  • -cannot break down adenine
  • -excess adenine
  • -feedback inhibition of ribonucleotide reductase
103
Q

inheritance of adenosine deaminase

A

autosomal recessive

104
Q

Lesch Nyhan syndrome

A

Loss of HGPRT

  • -block of guanine to GMP
  • -block of hypoxanthine to IMP
105
Q

Retardation, self mutilation

aggression, hyperuricemia, gout, and choreoathetosis in a kid

A

Lesch-Nyhan

106
Q

which amino acids are NOT degenerate?

A

methionine (AUG)

tryptophan (UGG)

107
Q

commaless, nonoverlapping genetic code

A

read from a fixed starting point. a continuous sequence of bases

108
Q

missense mutation

A

Changed amino acid

109
Q

single origin of replication

A

prokaryotes

110
Q

multiple origins of replication

A

eukaryotes

111
Q

fxn: DNA topoisomerases

A

Nick in helix=relieve supercoils

112
Q

DNA poly III

A

ONLY prokaryotic

–3’ to 5’ exonuclease activity for proofreading

113
Q

DNA poly I

A

prokaryotic only. degrades RNA primer and replaces it with DNA.
5’–>3’ exonuclease activity

114
Q

telomerase

A

Adds DNA to 3’ end of DNA to avoid loss of genetic material

115
Q

nucleotide excision repair

A

ENDONUCLEASES cut out oligonucleotides with damaged bases

116
Q

xeroderma pigmentosum

A

mutated nucleotide excision repair

117
Q

base excision repair

A

GLYCOSYLASES remove damaged bases

118
Q

base excision repair is important in

A

toxic or spontaneous deamination

119
Q

ataxia telangiectasia mutation

A

nonhomologous end joining

120
Q

what forms connection btw DNA bases?

A

3’ end OH attackes the phosphate on 5’

121
Q

most abundant RNA

A

rRNA

122
Q

longest RNA

A

mRNA

123
Q

smallest RNA

A

tRNA

124
Q

AUG in prokaryotes codes for

A

formylmethionine

125
Q

Promoter

A

Site where RNA poly and other transcription factors bind to DNA upstream from gene locus

126
Q

Enhancer

A

changes gene expression by binding transcription factors

127
Q

Silencer

A

repressors bind here

128
Q

Where are enhancers and silencers located?

A

Close to, far from, or within the gene

129
Q

RNA poly I

A

rRNA. most numerous type of RNA

130
Q

RNA poly II

A

mRNA, largest RNA

131
Q

RNA poly III

A

tRNA

132
Q

what’s different about the prokaryotic RNA?

A

it makes a single RNA polymerase

133
Q

pt eats a mushroom called amanita phalloides and dies. Very high LFTs. mechanism?

A

a-amanitin

  • -inhibits RNA polymerase II
  • -Causes severe hepatotoxicity if ingested
134
Q

heterogeneous nuclear RNA

A

initial RNA transcript. may NOT necessarily be translated

135
Q

pre-mRNA vs heterogeneous

A

pre-mRNA is DESTINED for translation

136
Q

where does mRNA processing occur?

A

In the nucleus.

–If no processing, then mRNA will NOT leave the nucleus

137
Q

three processing steps in mRNA

A
  1. 5’ 7-methylguanosine cap
  2. polyadenylation tail
  3. splicing
138
Q

polyadenylation signal

A

AAUAAA

139
Q

pre mRNA vs RNA

A

RNA has been processed and left the nucleus

140
Q

antibodies to snRNPs

A

lupus

141
Q

snRNP function

A

Forms a lariat to remove introns

142
Q

what is at the 3’ end of tRNA

A

CCA

143
Q

Aminoacyl-tRNA synthetase

A

scrutinizes amino acid before and after binding tRNA to it

144
Q

tRNA uses what energy source to attach AA?

A

ATP

145
Q

tRNA uses what energy source to translocate tRNA from one ribosomal site to another?

A

GTP

146
Q

antibiotic: binds 30 S and inhitibts formation of initiation complex, and causes misreading

A

aminoglycosides

147
Q

Block aminoacyl tRNA from entering acceptor site

A

tetracyclines

148
Q

Block peptidyl transferase

A

chloramphenicol

149
Q

Blocks release of tRNA after it has donated AA

A

macrolides

150
Q

trimming

A

removal of N/C propeptides from zymogens to generate mature proteins

151
Q

p53 and hypophosphorylated Rb inhibit

A

G1 to S progression

152
Q

RER vs cytosolic ribosomes

A

cytosolic ribosomes make proteins for intracellular use, not secretion.

153
Q

Golgi actions

A
  1. modifies N oligosaccharide on asparagine
  2. adds mannose-6 phosphate to proteins for trafficking to lysosomes
  3. Adds O oligosaccharides on serine/threonine
154
Q

coarse facial features
clouded cornea
restricted joint movement
high plasma levels of LYSOSOMAL enzymes

A

I cell disease.

155
Q

Cause of I cell disease

A

failure of addition of mannose 6 phosphate to lysosome proteins

156
Q

COPI protein

A

Transports within Golgi in RETROgrade fashion to ER

157
Q

COPII protein

A

Transports within Golgi in ANTEROgrade fashion from ER to golgi

158
Q

ubiquitin associated with

A

proteasome

159
Q

peroxisome breaks down

A

long fatty acids and amino acids

160
Q

bacterial infections
partial albinism
peripheral neuropathy

A

chediak higashi syndrome

161
Q

dynein

A

retrograde transport (+ to -)

162
Q

kinesin

A

anterograde transport (- to +)

163
Q

Drugs that act of microtubules

A

mebendazole
griseofulvin
cholchisine
paclitaxel

164
Q

WHat allows cilia to move?

A

axonemal dynein: an ATPase with a dynein arm

165
Q

Intermediate filaments are used for

A

maintaining structure

  • vimentin
  • desmin
  • cytokeratin
  • lamins
  • GFAP
166
Q

vimentin stains for

A

connective tissue

167
Q

desmin stains for

A

muscle

168
Q

cytokeratin stains for

A

epithelial cells

169
Q

GFAP stains for

A

neuroglia

170
Q

Neurofilaments stains for

A

neurons

171
Q

ouabain

A

inhibits the K bindings site of Na/K ATPase

172
Q

Type I collagen

A

bone, skin, tendon

173
Q

Type II collagen

A

cartilage

174
Q

Type III collagen

A

Reticulin

175
Q

Type IV collagen

A

Basement membrane

176
Q

Ehler danhlos has what collagen defect?

A

type III

177
Q

fibrillin fxn

A

sheath around elastin

178
Q

fibronectin fxn

A

Binds integrins on cell surface to ECM components (ex: collagen)

179
Q

Four steps of collagen synthesis INSIDE fibroblasts

A
  1. Synthesis (Gly-Pro-Lys)
  2. Hydroxylation of proline and lysine
  3. Glycosylation of hydroxylysine and triple helix formation held by H and disulfide bonds
  4. Exocytosis of procollagen into extracellular space
180
Q

Four steps of collagen synthesis OUTSIDE fibroblasts

A
  1. cleavage of disulfide terminal regions of procollagen=ins=insoluble
  2. cross linking of lysine-hydroxyllysine to make collagen
181
Q

vitamin C affects

A

hydroxylation of proline and lysine residues

182
Q

ehlers danlos affects what part of collagen synthesis?

A

cross linking of tropocollagen

183
Q

osteogenesis imperfecta inheritance

A

autosomal dominant

184
Q

ehler danlos associated with

A

joint dislocation
berry aneurysms
organ rupture

185
Q

Inheritance of alport syndrome

A

X linked recessive

186
Q

presentation of alport

A

progressive deafness and nephritis

187
Q

elastin fxn

A

stretchy component of skin, lungs, large arteries, ligamenta flava

188
Q

Elastin is rich in what components?

A

Proline and glycine

189
Q

what gives elastin its elastic properties

A

cross linking

190
Q

Southwestern blot

A

identifies DNA binding proteins

  • -with labeled oligonucleotides
  • -Example: Leucine zipper
191
Q

microarrays are used to detect

A

Single nucleotide polymorphism

192
Q

Indirect vs direct elisa

A

Indirect: uses an antigen to detect an antibody
Direct: uses a test antibody to detect an antigen

193
Q

RNA interference

A

dsRNA used to promote degradation of a target mRNA

194
Q

Lac I

A

repressor protein

195
Q

Lac P

A

promoter site

196
Q

Lac O

A

operator region

197
Q

Lac Z

A

B-galactosidase

198
Q

Lac Y

A

permease (lets lactose into cell)

199
Q

Describe Lac operon when lactose is not present

A

LAC I is being synthesized

  • -repressor protein binds to operator preventing transcription
  • -high glucose, low CAMP, no CAP binding
200
Q

Describe lac operon when lactose IS present

A

Lactose binds repressor protein made by Lac I

  • -operator is open
  • -polymerase attaches
201
Q

variable expressivity

A

phenotype varies among individuals with the same phenotype

202
Q

pleiotropy

A
one gene
multiple phenotypes (PKU)
203
Q

linkage disequilibrium

A

tendency for alleles at 2 loci to occur together more frequently than expected by chance

204
Q

Locus heterogeneity

A

mutations at different loci produce the same phenotype. Ex: albinism

205
Q

heteroplasmy

A

Presence of both normal and mutated mitochondrial DNA

206
Q

uniparental disomy

A

two copies of a chromosome from one parent, none from the other

207
Q

heterodisomy

A

offspring is heterozygous for alleles, both from one parent

208
Q

isodisomy

A

offspring is homozygous for alleles, both from one parent

209
Q

heterodisomy= error in meiosis I or II?

A

Meiosis I

210
Q

isodisomy=error in meiosis I or II?

A

Meisosis II

211
Q
mental retardation
hyperphagia
obesity
hypogonadism
hypotonia
A

prader willi

212
Q

mental retardation
seizures, ataxia
inappropriate laughter

A

angelman’s

213
Q

Praeder willi caused by

A

Paternal allele not expression (mom is always silenced)

214
Q

Angelman caused by

A

Maternal allele not expressed (dad is always silenced)

215
Q

Praeder willi and angelman’s syndromes are on chromosome

A

15

216
Q

stroke like episodes, lactic acidosis with ragged red fibers on modified Gomori trichrome stain

A

mitochondrial encephalopathy

217
Q

myoclonic epilepsi with ragged red fibers

A

MERRF

218
Q

achondroplasia inheritance

A

Dom

219
Q

FAP inheritance

A

dom

220
Q

cystic fibrosis inheritance

A

recessive

221
Q

albinism inheritance

A

recessive

222
Q

marfan’s inheritance

A

dominant

223
Q

MEN inheritance

A

dominant

224
Q

thalassemia inheritance

A

recessive

225
Q

huntington’s inheritance

A

dominant

226
Q

hereditary hemorrhagic telangiectasia (osler-weber, rendu) inheritance

A

dominant

227
Q

spherocytosis inheritance

A

dominant

228
Q

familial hypercholesterolemia inheritance

A

dominant

229
Q

glycogen storage disease inheritance

A

recessive

230
Q

hemochromatosis inheritance

A

recessive

231
Q

phenylketonuria inheritance

A

recessive

232
Q

sphingomyelinase inheritance

A

recessive

233
Q

ADPKD chromosome

A

16

234
Q

FAP chromosome

A

5

235
Q

ADPKD associated with

A

berry aneurysms

mitral valve prolapse

236
Q

telangiectasias,
nose bleeds
skin discolorations
AVMs

A

osler-weber rendu

237
Q

Huntington’s disease located on chromosome

A

4

238
Q

NF1 on chromosome

A

17

239
Q

NF2 on chromosome

A

22

240
Q

VHL on chromosome

A

3

241
Q

CF gene on chromosome

A

7

242
Q

fxn of CFTR channel

A
  1. secretes Cl- from lungs and GI tract
  2. reabsorbs Cl- from sweat

IN CF, this channel has a problem in post-translational processing, resulting in proteasomal degradation after synthesis

243
Q

Tx: CF

A

N-acetylcysteine to loosen mucus plugs

244
Q

X linked recessive disorders

A

B Wise Fool’s GOLD Has Silly HOpe

  • -Bruton’s x linked agammaglobulinemia
  • -Wiskott-Aldrich
  • -Fabry’s
  • -G6PD
  • -Ocular albinism
  • -Lesch-Nyhan
  • -Duchenne’s
  • -Hunter’s syndrome
  • -Ornithine transcarbamoylase deficiency
245
Q

huntington’s disease on chromosome

A

4

246
Q

Duchenne’s caused by

A

deleted dystrophin. Longest gene, so higher rate of spontaneous mutation

247
Q

Onset of becker’s

A

teens or YA

–Duchenne presents before 5 years of age

248
Q

Function of Duchenne’s

A

Anchors muscle fibers in skeletal and cardiac

249
Q

achondroplasia gene

A

FGF3

250
Q

Large testes, jaw, and ears
autism
mitral valve prolapse

A

Fragile X

251
Q

Fragile X gene

A

FMR1

252
Q

trinucleotide in fragile X

A

CGG

253
Q

myotonic distrophy mutation

A

CTG

254
Q

friederich’s ataxia mutation

A

GAA

255
Q

dx of CF

A
  1. excess chloride in sweat

2. transepithelial potential difference

256
Q

pyruvate kinase

A

PEP–>pyruvate

257
Q

lactate dehydrogenase

A

pyruvate–>lactic acid

258
Q

pyruvate decarboxylase

A

pyruvate–>oxaloacetate

259
Q

Pyruvate dehydrogenase

A

pyruvate–>acetylcoA

260
Q

ultrasound shows increased nuchal translucency in first trimester

A

down’s syndrome or patau

261
Q

quad screen in down’s syndrome

A
  1. decreased a-FP
  2. Increased bHcG
  3. decreased estriol
  4. increased inhibin A
262
Q

Down’s syndrome=increased risk of

A

ALL

Alzheimer’s

263
Q

Quad screen

  1. low aFP
  2. low hCG
  3. low estriol
  4. normal inhibin A
A

Edwards

264
Q

Quad screen

  1. low hCG
  2. low pAPP-A
  3. Increased nuchal translucency
A

patau

265
Q

most common cause of Down’s

A

meiotic nondisjunction

266
Q

mental retardation, rocker bottom feet, congenital heart disease
–low set ears, micrognathia

A

Edwards. Die within 1 year

267
Q

mental retardation, rocker bottom feet, congenital heart disease

  • -cleft lip
  • -polydactyly
  • -holoprosencephaly
A

Patau. Die within 1 year

268
Q

Robertsonian translocation

A

when short arms of chromosome are lost. balanced translocations usually are normal.

269
Q

robertsonian translocation occurs on chromosome pairs

A

13,14,15,21,22

270
Q

baby with high pitched mewing

  • -microcephaly
  • -retardation
  • -epicanthal folds
  • -VSD
A

Cri du chat

271
Q

deletion in cri du chat

A

chromosome 5p

272
Q

elfin facies

  • -hypercalcemia
  • -extreme friendliness with strangers
  • -cardiovacscular problems
A

williams

273
Q

Williams caused by deltion on

A

chromosome 7. includes deletion of elastin gene

274
Q

22q11 deletion sx

A

CATCH 22

  • Cleft palate
  • abnormal facies
  • thymic aplasia
  • cardiac defects
  • hypocalcemia
275
Q

digeorge

A

22q11

-thymic, parathyroid, cardiac problems

276
Q

velocardiofacial syndrome

A

22q11

-palate, facial, cardiac defect

277
Q

vitamin toxicity most common with which vitamins?

A

A,D,E,K

278
Q

B1

A

thiamine

279
Q

B2

A

riboflavin

280
Q

B3

A

niacin

281
Q

B5

A

pantothenic acid

282
Q

B6

A

pyridoxine

283
Q

B7

A

biotin

284
Q

B9

A

folate

285
Q

vitamin C

A

ascorbic acid

286
Q

which water soluble vitamins are stored for a long time in the body?

A

B12 and folate (in liver)

287
Q

night blindness and dry skin

A

Vitamin A deficiency

288
Q

arthralgias, fatigue, alopecia, sore throat, headaches

A

vitamin A excess

289
Q

Thiamine is a cofactor for

A
  1. pyruvate dehydrogenase
  2. alpha ketoglutarate dehydrogenase
  3. transketolase
  4. branched chain amino acid dehydrogenase
290
Q

alcoholic with malnutrition presents with polyneuritis, and symmetrical muscle wasting

A

Dry beriberi

291
Q

alcoholic with malnutrition presents with dilated cardiomyopathy and edema

A

wet beri beri

292
Q

riboflavin function

A

Cofactor in oxidation and reduction (FADH2)

293
Q

cheilosis, corneal vascularization

A

vitamin B2 deficiency

294
Q

niacin fxn

A

NAD and NADP+ component

295
Q

niacin is derived from

A

tryptophan

296
Q

synthesis of niacin requires

A

B6

297
Q

pellagra

A

niacin deficiency

298
Q

diarrhea, dementia, dermatitis

A

pellagra

299
Q

hartnup disease

A

decrease in tryptophan absorption

300
Q

causes of niacin deficiency

A
  1. malignant carcinoid (use up all your tryptophan)
  2. INH (low B6)
  3. pellagra
301
Q

fxn: pantothenate

A

component of CoA and fatty acid synthase

302
Q

dermatitis, enteritis, alopecia

–adrenal insufficiency

A

B5 deficiency

303
Q

pyridoxine fxn:

A
  1. heme synthesis
  2. neurotransmitter synthesis
  3. transamination, decarboxylation, and glycogen phosphorylase
304
Q

convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemias

A

pyridoxine deficiency

305
Q

Biotin fxn

A
  1. pyruvate carboxylase
  2. acetyl coA carboxylase (acetylCoA–>malonylCoA)
  3. propionyl-CoA carboxylase (propionyl-CoA–>methylmalonylCoA)
306
Q

excessive ingestion of raw eggs with dermatitis, alopecia, enteritis

A

biotin deficiency

307
Q

Folic acid use

A

Makes THF, tetrahydrofolate

308
Q

B12 vs folate deficiency

A

B12 has neuro symptoms

309
Q

which vitamins do you get from leafy green veggies?

A
  1. Vitamin A

2. Vitamin B9 (folate)

310
Q

vegans at risk for which vitamin deficiency?

A

B12

311
Q

subacute combined degeneration

A

B12 deficiency

312
Q

infectious cause of B12 deficiency

A

diphyllobothrium latum

313
Q

B12 is a cofactor for

A
  1. homocystein methyltransferase

2. methylmalonyl-CoA

314
Q

S-adenosyl-methionine

A

donates methyl units

–converts NE to epinephrine

315
Q

regeneration of methionine is dependent on

A

B12 and folate

316
Q

methionine is made of

A

homocystein + CH3

317
Q

To regenerate homocystein, you need

A

homocystein methyltransferase

–>Addsmethyl group from THF-CH3

318
Q

vitamin C helps with the absorption of

A

iron. Therefore, don’t give to people with hemochromatosis or regular transfusions

319
Q

vitamin C fxn

A

hydroxylation of proline and lysine in collagen synthesis

–dopamine B hydroxylase: converts dopamine to NE

320
Q

hypercalcemia and hypercalciuria in pt taking too many vitamins

A

Vitamin D overdose.

321
Q

vitamin D overdose is more common in what condition?

A

sarcoidosis

322
Q

Vitamin E fxn

A

protects erythrocytes and membranes from free radical damage

323
Q

hemolytic anemia and posterior column demyelination: what vitamin deficiency?

A

vitamin E. E is for erythrocytes

324
Q

Vitamin K fxn

A

gamma carboxylation of gutamic acid on clotting proteins

325
Q

which vitamins are missing from breast milk?

A

Vitamin D and K

326
Q

loss of smell, delayed wound healing, hypogonadism, and decreased adult hair

A

ziinc deficiency–predisposes to alcoholic cirrhosis

327
Q

fomepizole use

A

For methanol or ethylene glycol poisoning

328
Q

mech: fomepizole

A

inhibits alcohol dehydrogenase

329
Q

disulfiram mechanism

A

inhibits acetaldehyde dehydrogenase

330
Q

Explain how ethanol causes acidosis and fatty acid synthesis and hypoglycemia

A

All caused by increased push to regenerate NAD+

  1. pyruvate–>lactic acid
  2. oxaloacetate–>malate
    - ->malate excess inhibits gluconeogenesis
    - ->shuts down TCA cycle
    - ->acetylcoA goes to ketone
    - ->excess NADPH from breakdown of malate
    - ->fatty acid synthesis
331
Q

Kid with malnutrition, edema, anemia, and fatty liver

A

Kwashiorkor

332
Q

marasmus

A

muscle wasting from malnutrition

333
Q

Fatty acid synthesis occurs in the

A

cytoplasm

334
Q

HMP shunt occurs in the

A

cytoplasm

335
Q

acetylcoA production occurs in the

A

mitochondria

336
Q

Which processes occur both in the mitochondria and cytoplasm?

A

heme

gluconeogenesis

337
Q

RDS glycolysis

A

PFK1

338
Q

RDS gluconeogenesis

A

F1,6 bisphosphonate

339
Q

RDS TCA cycle

A

isocitrate dehydrogenase

340
Q

RDS glycogen synthesis

A

glycogen synthase

341
Q

RDS glycogenolysis

A

glycogen phosphorylase

342
Q

RDS HMP shunt

A

g6PD

343
Q

RDS pyrimidine synthesis, de novo

A

carbamoylphosphate synthetase II

344
Q

RDS purine synthesis de novo

A

glutamine PRPP amidotransferase

345
Q

RDS urea cycle

A

carbamoyl phosphate synthetase I

346
Q

RDS fatty acid synthesis

A

AcetylCoA carboxylase

347
Q

RDS fatty acid oxidation

A

carnitine acyltransferaseI

348
Q

RDS ketogenesis

A

HMG coA synthase

349
Q

What regulates carnitine acyltransferase I in fatty acid oxidation?

A

malonyl coA inhibits

350
Q

Glucokinase found in

A

Liver and beta cells of the pancreas.

351
Q

which is induced by insulin, glucokinase or hexokinase?

A

glucokinase. High capacity but low affinity

352
Q

Very long chain fatty acids are degraded by

A

peroxisomes. Cannot undergo beta oxidation by mitochondria

353
Q

8 month old with hyperactivity, tremor, and seizures. Pt has blue eyes, fair skin, and mousy odor

A

Phenylketonuria

354
Q

What do you need to supplement PKU with?

A

Tyrosine. Can no longer synthesis tyrosine from phenylalanine

355
Q

Describe the G protein pathway

A
  1. Activation of adenylate cyclase
  2. Activation of protein kinase A
  3. physiologic effects
356
Q

Which hormones use G protein receptors?

A
  1. TSH
  2. Glucagon
  3. PTH
  4. Beta adrenergic receptors
357
Q

Pt presents with increased serum methionine and severe chest pain and MI

A

homocystinuria.

–defect in cystathionine beta synthetase (converts homocystine to cystathionine.

358
Q

Most common cause of PKU

A

deficiency of phenylalanine hydroxylase

359
Q

mutation in Sickle Cell Disease

A

Pt replaces glutamate with valine, a nonpolar amino acid. This changes the charge
–In hemoglobin C, lysine replaces the glutamate residue, making it less negatively charged. Usually asymptomatic but mild hemolytic anemia and splenomegaly

360
Q

Effect of hyperammonia in the brain

A

depletion of glutamate and accuulation of glutamine

361
Q

ALA synthase requires what vitamin?

A

pyridoxal phosphaet

362
Q

tyrosine kinase effect after binding

A

phosphorylation of protein phosphatase

363
Q

Why is Fructose 1 phosphate metabolized much faster than glucose?

A

It bypasses the major regulatory step in glycolysis=PFK1

364
Q

HGPRT converts

A

guanine back to GMP
and
Hypoxanthine to IMP

365
Q

adenosine deaminase

A

coverts adenosine to inosine to be broken down to hypoxanthine or recycled to IMP

366
Q

16S rRNA in prokaryotic ribosome

A

Contains complementary mRNA sequence necessary for binding shine delgarno and translation

367
Q

Translocation of aatRNA requires

A

GTP

368
Q

23S rRNA

A

facilitates peptide bond formation

369
Q

which vitamin can you give to a kid with measles?

A

vitamin A

370
Q

how is alanine converted back to pyruvate?

A

combined with a-ketoglutarate

371
Q

Describe the mTOR pathway

A
  1. autophosphorylation of tyrosine
  2. Phosphoinositide 3 kinase activation
  3. Activation of protein kinase B
  4. Increased gene transcription
    - -THIS PATHWAY IMPORTANT IN APOPTOSIS AND CEL PROLIFERATION