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USMLE GAME TIME > Biochemistry - Important Concepts > Flashcards

Biochemistry - Important Concepts Flashcards

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USMLE® Step 1 flashcards
1
Q

Amino acids in histones

A

Lysine and arginine

His lies made me go “argh!”

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2
Q

Nucleosome core

A

H2A, H2B, H3, H4

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3
Q

H1

A

Binds to the nucleosome and to linker DNA, stabilizing the chromatin fiber

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4
Q

During what phase of the cell cycle does histone synthesis occur?

A

S phase

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5
Q

Heterochromatin

A

Condensed and inactive

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6
Q

Euchromatin

A

Sterically accessible

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7
Q

Amino acids necessary for purine synthesis

A

GAG
Glycine
Aspartate
Glutamine

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8
Q

Leflunomide

A

Inhibits dihydroorotate dehydrogenase (carbamoyl phosphate + aspartate + PRPP –> orotic acid

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9
Q

Mycphenolate

A

Inhibits IMP dehydrogenase

My Ribald IMP

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10
Q

Ribavarin

A

Inhibits IMP dehydrogenase

My Ribald IMP

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11
Q

Hydroxyurea

A

Inhibits ribonucleotide reductase (which turns UDP –> dUMP or converts ribonucleotides to deoxyribonucleotides)

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12
Q

6-mercaptopurine

A

Inhibits de novo purine synthesis

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13
Q

Azathioprine

A

Inhibits de novo purine synthesis

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14
Q

Pyrimethamine

A

Inhibits dihyrofolate reductase and decreases dTMP

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15
Q

Mnemonic for pyrimidine base production

A

Gluttons crave carbs as oral porn

Glutamine Carbamoyl phosphate synthase II Carbamoyl phosphate Aspartate Orotic acid PRPP

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16
Q

HGPRT catalyzes what rxns?

A

Guanine to GMP

Hypoxanthine to IMP

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17
Q

Adenosine deaminase does what?

A

Adenosine to Inosine (irreversibly deaminates adenosine - substitutes an amino group for a hydroxyl group)

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18
Q

Xanthine oxidase does what?

A

Hypoxanthine to xanthine, xanthine to uric acid.

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19
Q

Adenosine deaminase deficiency

A

Leads to excess ATP and dATP, which imbalances nucleotide pool via feedback inhibition of ribonucleotide reductase - DNA synthesis is prevented - lymphocyte count decreases

AR SCID

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20
Q

Purine nucleoside phosphorylase deficiency

A

Catalyzes the reaction from Inosine to Hypoxanthine. Increased purine nucleosides, decreased uric acid, and impaired T cell function.

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21
Q

Lesch-Nyhan syndrome sx?

A 
HGPRT: 
Hyperuricemia 
Gout
Pissed off (aggressive, self-mutilating)
Retardation
DysTonia

Also choreathoid movements

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22
Q

Lesch-Nyhan syndrome treatment?

A

Allopurinol and Febuxostat (inhibit xanthine oxidase)

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23
Q

Mycophenolate mofetil

A

Anti-metabolite, anti-proliferative drug that acts as an inhibitor of inosine monophosphate dehydrogenase and is used to treat Wegener’s… somehow

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24
Q

DNA polymerase delta

A

Major eukaryotic replication polymerase

beta - repair
alpha and epsilon - also involved in replication
gamma - mitochondrial DNA

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25
Q

DNA polymerase beta

A

beta - repair
delta - major eukaryotic replication polymerase
alpha and epsilon - also involved in replication
gamma - mitochondrial DNA

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26
Q

DNA polymerase III

A

Prokaryotic only. Proofreads with 3’ to 5’ exonuclease.

III only eats what’s behind it
I is aggressive - chomps as it goes forward, like Pacman

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27
Q

DNA polymerase I

A

Prokaryotic only. Proofreads with 5’ to 3’ exonuclease. THis is used to degrade RNA primer.

III only eats what’s behind it
I is aggressive - chomps as it goes forward, like Pacman

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28
Q

Transition mutation

A

purine to purine or pyrimidine to pyrimidine

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29
Q

Transversion mutation

A

purine to pyrimidine or vice versa

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30
Q

Wobble rules

A

Third base pair contributes to wobble.
U-G is a valid pair
Inosine can pair with U, C, A

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31
Q

AA with strongly nonpolar side chains have codons with ___s in 2nd position.

A

Pyrimadines

Polar side chains –> purines

Remember - polar bears are pure.

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32
Q

Xeroderma pigmentosum type of DNA repair problem?

A

Nucleotide excision repair

Think derma –> skin –> UV exposure

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33
Q

HNPCC repair problem?

A

Mismatch repair

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34
Q

Ataxia telangiectasia repair problem?

A

Nonhomologous end joining

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35
Q

Nucleotide excision repair

A

Repair of pyrimidine dimers or bulky helix-distorted lesions usually from UV light exposure.

A short section is excised using endonucleases and then DNA polymerase and ligase fills and reseals the gap.

Xeroderma pigmentosum

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36
Q

Base excision repair

A

Altered base - repairs spontaneous / toxic deamination (C –> U, A –> hypoxanthine)

GEL PLease!
Glycosylase (base-specific) recognizes altered base and creates an apyrimidinic, apurinic site
Endonuclease removes nucleotide and cleaves 5’ end
Lyase cleaves 3’ end
Pol beta fills gap
Lyase seals it.

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37
Q

Mismatch repair

A

Defect in newly synthesized strand.

M2ESS PLease
MutS detects mismatch
MutL identifies parent strand
Exonuclease 1 is activated
SSBPs stabilize the construct
Pol delta synthesizes new DNA
Ligase seals the nick

HNPCC

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38
Q

NHEJ

A

Brings together 2 ends of DNA fragments to repair double strand breaks; no requirement for homology

Ataxia telangiectasia

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39
Q

DNA denaturation

A

Hyperchromic effect - increase in UV absorption and A260

Decrease viscosity

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40
Q

Where do capping, splicing, and polyadenylation of 3’ end of RNA occur?

A

All in the nucleus

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41
Q

hnRNA versus mRNA?

A

hnRNA - heterogeneous nuclear RNA - not spliced or capped or polyadenylated

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42
Q

Cytoplasmic P-bodies?

A

These are responsible for mRNA quality control - they contain exonucleases, decapping enzymes, and microRNAs.

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43
Q

Polyadenylation signal

A

AAUAAA

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44
Q

anti-smith antibodies

A

Antibodies to spliceosomal snRNPs - highly specific for SLE

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45
Q

anti-U1 RNP antibodies

A

highly associated with mixed connective tissue disease

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46
Q

Exons

A

Contain the actual genetic material coding for proton

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47
Q

Introns

A

Intervening noncoding segments of DNA

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48
Q

Which end is the CCA at in tRNA?

What does it do?

A

3’ end

Accepts the amino acid

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49
Q

T-arm

A

Think Tribe
Thiamine, pseudouracil, cytosine
t-RNA ribosome binding

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50
Q

D-arm

A

Think D-syn
Contains dihydrouracil residues
Necessary for tRNA recognition by the correct amino-acyl tRNA synthetase

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51
Q

Which stages require ATP and which require GTP?

A

ATP - tRNA activation and charging

GTP - tRNA gripping and going places

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52
Q

Sites on the 60S subunit

A

A - incoming aminoacyl tRNA
P - accomodates growing peptide
E - holds empty tRNA as it exits

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53
Q

Release factor

A

Recognizes the stop codon, causes completed polypeptide to be released from the ribosome

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54
Q

Zymogen

A

Inactive enzyme precursor

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55
Q

CDKs

A

Constitutive and inactive

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56
Q

Cyclins

A

Regulatory proteins that control cell cycle events - activate CDKs

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57
Q

Breast cancer, brain tumors, acute leukemia, soft tissue sarcomas, bone sarcomas, and adrenal cortical carcinoma

A

Li-Fraumeni syndrome

p53 mutation, AD. rare

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58
Q

Nissl bodies

A

RER in neurons that synthesize peptide neurotransmitters for secretion

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59
Q

Smooth endoplasmic reticulum

A

Site of steroid synthesis and detoxification of drugs and poisons

Liver hepatocytes and steroid-hormone producing cells in the adrenal cortex and gonads are rich in SER.

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60
Q

Golgi modifications

A

N-oligosaccharide on asparagine
O-oligosaccharide on serine and threonine
Mannose-6-phosphate addition to proteins for lysosomal trafficking.

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61
Q

Endosomes

A

Sorting centers for material from outside the cell or from the Golgi, sending it to lysosomes for destruction or back to the membrane / Golgi for further use.

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62
Q

Coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes - fatal in childhood

A

I cell disease
Inherited lysosomal storage disorder
Defect in phosphotransferase - Golgi fails to phosphorylate mannose residues (mannose 6 phosphate) on glycoproteins so proteins are screted extracellularly rather than delivered to lysosomes

Think clouds and corn on the golf course - restricted movement because you can’t see - Eyes - I cell disease

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63
Q

I cell disease

A

Coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes - fatal in childhood

Inherited lysosomal storage disorder
Defect in phosphotransferase - Golgi fails to phosphorylate mannose residues (mannose 6 phosphate) on glycoproteins so proteins are screted extracellularly rather than delivered to lysosomes

Think clouds and corn on the golf course - restricted movement because you can’t see - Eyes - I cell disease

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64
Q

Phosphotransferase

A

I cell disease

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65
Q

Signal recognition particle

A

Abundant cytosolic ribonucleoprotein that trafficks proteins from the ribosome to the RER. Absent or dysfunctional SRP causes proteins to accumulate in the cytosol.

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66
Q

COPI

A

Golgi –> Golgi (retrograde)
Golgi –> ER

COPII is anterograde
Gotta go backwards to fix your past before you can go forward! said the Cop

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67
Q

COP II

A

Golgi -> Golgi (anterograde)
ER -> Golgi
Gotta go backwards to fix your past before you can go forward! said the Cop

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68
Q

Clathrin

A

Golgi -> lysosomes

Plasma membrane -> endosomes (receptor mediated endocytosis)

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69
Q

Peroxisome

A

Catabolizes very long chain fatty acids, branched chain fatty acids, and amino acids

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70
Q

Proteasome

A

Degrades damaged or ubiquitin tagged protein

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71
Q

Peroxisome vs proteasome?

A

Peroxisome is fatty acids and amino acids

Proteasome is protein

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72
Q

Dynein versus kinesin?

A

Dynein is Minus end directed microtubule transport - goes TOWARD the cell center

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73
Q

Drugs that act on microtubules?

A 
Pack My Bendy Greasy Collar of Vines
Paclitaxel
Mebendazole
Griseofulvin
Colchicine
Vincristine/Vinblastine
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74
Q

Axonemal dynein

A

ATPase ta links peripheral 9 doublets in cilia and causes bending of cilium by differential sliding of doublets.

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75
Q

Infertility, Increased risk of ectopic pregnancy, bronchiectasis, recurrent sinusitis, situs inversus

A

Kartagener syndrome - primary ciliary dyskinesia

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76
Q

Actin and myosin versus microtubules versus intermediate filaments

A

Actin / myosin - Muscle contraction
Microtubule - Movement
Intermediate filament - Structure

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77
Q

Intermediate filament stain - vimentin

A

Stains Connective tissue

Vines connect

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78
Q

Intermediate filament stain - Desmin

A

Stains muscle

Desmond is muscular

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79
Q

Cytokeratin stain

A

Epithelial cell

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80
Q

GFAP stain

A

NeuroGlia

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81
Q

Neurofilament stain

A

Neurons

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82
Q

Ouabain

A

Inhibits by binding to K+ site on sodium potassium pump

83
Q

Cardiac glycosides

A

Directly inhibit Na+/K+-ATPase which leads to indirect inhibition of Na+/Ca2+ exchange and increases Ca2+ and cardiac contractility

84
Q

Collagen types

A

Be so totally cool, read books
Type I - bone, skin, tendon (dentin, fascia, cornea, late wound repair)
Type II - Cartilage (including hyaline), vitreous body, nucleus pulposis (CaVerN)
Type III - Reticulin - skin, blood vessels, uterus, fetal tissue, granulation tissue (Grub fuss)?
Type IV - Basement membrane, basal lamina, lens

I - bone
II - cartwolage
III - threeD (vascular Ehlers-Danlos)
IV - under the floor

85
Q

Glomerulonephritis, ESRD, hearing loss, may be eye problems

Basket-weave appearance on EM of the glomeruli.

A

Alport syndrome. Caused by Type IV collagen mutation.

86
Q

Which type of collagen is targeted by antibodies in Goodpasture?

A

GBM

87
Q

Type II collagen

A

Cartilage, Vitreous body, Nucleus pulposis

88
Q

Type IV collagen

A

Basement membrane
Basal lamina
Lens

89
Q

Type I collagen

A

Bone, Skin, Tendon, Dentin, fascia, cornea, late wound repair

90
Q

Type III

A

Reticulin - skin, blood vessels, uterus, fetal tissue, granulation tissue

91
Q

Steps of collagen synthesis

A
  1. Synthesis - translation of preprocollagen (Gly-X-Y, usu proline or lysine)
  2. Hydroxylation of proline and lysine residues - requires VITAMIN C
  3. Glycosylation of pro-alpha-chain hydroxylysine residues and formation of procollagen thru disulfide bonds (triple helix) – OSTEOGENESIS IMPERFECTA
  4. Exocytosis into cellular space
  5. Cleavage of terminal disulfide-rich regions -> becomes insoluble tropocollagen
  6. Covaent lysine-hydroxylase cross linking by lysyl oxidase occurs to make collagen fibrils. EHLERS DANLOS OR MENKES DISEASE
92
Q

Multiple fractures with minimal trauma; may occur during the birth process. Hearing loss. Dental imperfections.

A

Also blue sclera

Dental imperfections due to lack of dentin

Osteogenesis imperfecta, due to defect in triple helix formation in the glycosylation step of collagen I synthesis.
Most common form is Autosomal Dominant.

93
Q

Hyperextensible skin, tendency to bleed / easy bruising, hypermobile joints, joint dislocation, berry and aortic aneurysms, organ rupture.

A

Ehlers-Danlos syndrome

Classical type - joint and skin symptoms - Type V collagen mutation
Vascular type - Deficient Type III collagen

94
Q

What causes Ehlers-Danlos syndrome?

A

6+ types but listed as defective crosslinking (final step in collagen pathway) in the book.

95
Q

Brittle, kinky hair, growth retardation, hypotonia

A

Menkes Disease

Connective tissue disease caused by impaired copper absorption and transport - leads to decreased activity of lysyl oxidase (since copper is the necessary cofactor).

96
Q

Amino acids in collagen?

A

Glycin, proline and lysine (the latter 2 hydroxylated)

97
Q

Amino acids in elastin?

A

Proline and glycine, nonhydroxylated

98
Q

Fibrillin

A

Glycoprotein forming sheath around elastin, mutated in Marfan syndrome

99
Q

Indirect ELISA

A

Use a test antigen to see if a specific antibody is present in the patient’s blood - a secondary antibody coupled to a color generating enzyme is added to detect the first antibody

100
Q

Direct ELISA

A

Use a test antibody to see if a specific antibody is present in patient’s blood - secondary antibody coupled to a color-generating enzyme is added to detect antigen.

101
Q

What can you use to perform karyotyping?

A

Blood, bone marrow, amniotic fluid, or placental tissue

102
Q

Variable expressivity versus incomplete penetrance

A

Incomplete penetrance is the all or none one

103
Q

Pleiotropy

A

One gene contributes to multiple phenotypic effects

104
Q

Linkage disequilibrium

A

Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance

105
Q

Locus heterogeneity

A

Mutations at different loci can produce a similar phenotype

Albinism

106
Q

Allelic heterogeneity

A

Different mutations in the same locus produce the same phenotype

107
Q

Polycystic fibrous displasia, unilateral cafe au lait spots, autonomous endocrine hormone excess with precocious puberty

A

McCune-Albright syndrome - An example of a mosaic disorder

Mutation of the GNAS1 gene involved in G protein signalling which prevents cAMP downregulation.

108
Q

Uniparental disomy

A

Offspring receives 2 copies of a chromosome from 1 parent and none from another

109
Q

Heterodisomy

A

Indicates a meiosis 1 error - heterozygous

110
Q

Isodisomy

A

Indicates a meiosis II error - homozygous - or postzygotic chromosomal duplication of one of a pair and loss of the other

111
Q

Frequency of X linked recessive disease in males vs females

A

q vs q^2

112
Q

Hyperphagia, hypogonadism, hypotonia, obesity, intellectual disability

A

Prader-Willi syndrome

113
Q

Inappropriate laughter, seizures, ataxia, severe intellectual disability

A

Angelman sydndrome, paternally imprinted

114
Q

Hypophosphatemic rickets

A

Inherited X linked dominant disorder resulting in increased phosphate wasting at the proximal tubule - presents like Rickets.

115
Q

Myopathy, latic acidosis, and CNS disease.

Muscle biopsy shows ragged red fibers

A

Mitochondrial myopathy - a secondary failure in oxidative phosphorylation

116
Q

Telangiectasia, recurrent epistaxis, skin discolorations, AVMs, GI bleeding, hematuria

A

Osler-Weber-Rendu syndrome / Hereditory Hemorrhagic telangiectasia

Associated with TGF-beta

As we run (osler weber rendu), we tug a betafish (TGFbeta) which bleeds everywhere

117
Q

Pectus excavatum

A

Chest having a sunken in appearance

118
Q

Which way do the lenses subluxate in marfans?

A

Upward and temporally

119
Q

Chromosome associated with FAP?

A

APC gene, chromosome 5, 5 letters in polyp

120
Q

Chromosome associated with ADPKD?

A

16 letters in polycystic kidney
85% cases due to PKD1 mutation
remainder due to PKD2 (chromosome 4)

121
Q

Most common gene defect associated with CF?

A

CFTR defect on chromosome 7 - commonly a deletion of Phe508

Fennel gives you cysts or is made of fiber

122
Q

What electrolyte imbalances do you see with CF?

A

Hypokalemia and contraction alkalosis because H2O / Na+ losses lead to concomitant renal K+ and H+ wasting

123
Q

Meconium ileus

A

Bowel obstruction, occurs when the meconium of the newborn is thicker and stickier than normal meconium

124
Q

Treatment for CF

A 
N-acetylcysteine to loosen mucus plugs (cleaves disulfide bonds within mucus glycoproteins) 
Dornase alpha (DNAse) to clear leukocytic debris
125
Q

X-linked disorders

A

Brutish Dutch Hunters Give Fat Bloody Leeches to the Wise Blind Oracle

Bruton agammaglobulinemia
Duchenne
Hunter Syndrome
G6PD
Fabry
Hemophelia
Lesch-Nyhan
Wiskott-Aldrich
Ocular albinism
Ornithine transcarbamylase deficiency
126
Q

Diagnosis of Duchenne

A

Loss of dystrophin – myonecrosis
Increase CPK and aldolase
Western blot, muscle biopsy to confirm

127
Q

Myotonia, muscle wasting, frontal balding, cataracts, testicular atrophy, arrhythmia

A

Myotonic Type I

Defect in myotonin protein kinase (DMPK gene) - specifically CTG trinucleotide repeat expansion

Think bald guy who won’t let go (myotonia) of his love (arrhythmia/heartache) even tho he has cataracts, testicular atrophy…

128
Q

Trinucleotide repeat expansion diseases

A

Try hunting for my fried eggs
X-girlfriend’s first aid helped ace my test

Fragile X - CGG
Friedrich - GAA
Huntington - CAG
Myotonic dystrophy - CTG

129
Q

Intellectual disability, elfin facies, hypercalcemia, well-developed verbal skills, extreme friendliness with strangers, cardiovascular problems

A

Williams syndrome - congenital microdeletion of long arm of chromosome 7

Think Robin Williams; he was lucky (7) to have elfin facies, strong verbal skills, extreme friendliness, also had heart surgery so cards problem
He was hyper in california (hypercalcemia)

130
Q

What type of heart defect is associated with Downs?

A

Ostium primum type ASD

131
Q

Small white or grayish brown spots on the periphery of the iris due to connective tisue aggregation

A

Brushfield spots - Down syndrome

132
Q

First semester ultrasound for Downs

A

increased nuchal translucency and hypoplastic nasal bone
Serum PAPP-A down
Free beta HCG is up

133
Q

Second trimester quad for Downs

A

down up down up

alpha feto, beta hcg, estriol, inhibin a

134
Q

Severe intellectual disability with rocker-bottom feet, micrognathia, low-set ears, clenched hands, prominent occiput, congenital heart disease; death in 1 year

A

Edwards syndrome - trisomy 18

135
Q

Findings for Edward syndrome

A

PAPP A and free beta hCG down in first trimester

Quad is all don

136
Q

Severe intellectual disability, rocker bottom feet, microopthalmia, microcephaly, cleft lip and palate, holoprosencephaly, polydactyly, CHD, death in 1 year

A

13

first trimester creen - decreased beta hcg, PAPP-A, and increased nuchal translucency

137
Q

Robertsonian translocation

A

Nonreciprocal chromosomal translocation that commonly involves 13, 14, 15, 21, 22 - long arms fuse with long arms

138
Q

Cri du Chat

A

chromosome 5 microdiletion

Microcephaly
Moderate to severe disability
HIgh pitched crying / mewing
epicanthal folds
Cardiac abnormality - VSD

Cats venture (ventricles) toward the crying baby and give him a high 5.

139
Q

Is toxicity more common for fat or water soluble vitamins?

A

Fat soluble

140
Q

Which water soluble vitamins don’t wash out easily?

A

B12 and folate (stored in liver)

141
Q

Night blindness, dry, scaly skin, alopecia, corneal degeneration, immune suppression

A

Vitamin A deficiency

Think blind, scaly, hairless, sick - sounds like Lord Voldemort’s soul

142
Q

Arthralgias, skin changes / scaly, alopecia, cerebral edema, osteoporosis, hepatic abnormalities

A

Also pseudotumor cerebri, teratogenic

Vitamin A excess symptoms.

143
Q

What vitamin is used to treat measles?

A

Vitamin A

144
Q

What vitamin is used to treat AML, subtype M3?

A

A

145
Q

What is thiamine a cofactor for?

A
  1. Pyruvate dehyrogenase
  2. alpha ketoglutarate dehydrogenase
  3. transketolase
  4. branched chain ketoacid dehydrogenase
146
Q

Confusion, opthalmoplegia, ataxia

A

Wernicke-Korsakoff - also confabulation, personality change, memory loss. Damage to medial dorsal nucleus of thalamus and mammilary bodies

147
Q

Polyneuritis and symmetrical muscle wasting associated with thiamine

A

Dry beri beri

148
Q

HIgh output cardiac failure (dilated) and edema associated with thiamine deficiency

A

Wet beri beri

149
Q

How do you diagnose thiamine deficiency?

A

Increase in RBC transketolase activity following vitamin B1 administration

150
Q

Cheilosis, corneal vascularization, angular cheilitis, glossitis, scaly dermatitis

A

Vitamin B2 deficiency

151
Q

What vitamins does niacin need to be synthesized?

A

B2, B6

152
Q

Diarrhea, dementia, dermatitis

A

Niacin deficiency, pellagra

153
Q

Casal necklace or hyperpigmentation of sun-exposed limbs

A

Niacin deficiency, pellagra

154
Q

Hartnup disease

A

Decreased tryptophan absorption

155
Q

Carcinoid syndrome

A

Vasoactive tumor substances enter systemic circulation - flushing, diarrhea, serotonin-induced fibrosis of valvular epithelium

156
Q

Dermatitis, enteritis, alopecia, adrenal insufficiency

A

B5 - pantothenate deficiency

157
Q

B5

A

Essential component of coenzyme A and fatty acid synthase

158
Q

B6

A 
Converted to pyridoxal phosphate: used in
GladiaTr
Glycogen phosphorylase
Decarboxylation rxns
Transamination rxns (AST, ALT)

Synthesis of neurotransmitters, cystathionine, heme, niacine, histamine, etc

159
Q

Convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemia

A

B6 deficiency

160
Q

B7

A

Cofactor for carboxylation enzymes :

  1. Pyruvate carboxylase
  2. Acetyl-CoA carboxylase
  3. Propionyl-CoA carboxylase
161
Q

Dermatitis, alopecia, enteritis after eating raw egg whites

A

B7 deficiency

162
Q

Folic acid

A

Coenzyme for 1-carbon transfer/methylation reactions

No neurologic symptoms

163
Q

Drugs that can cause folate deficiency

A

Prim Fools Trim Pyromaniac phoenixes with no Defense Method

Primidone
Folate
Trimethoprim
Pyrimethamine
Phenytoin
Diphenhydantoin / anticonvulsants
Methotrexate
164
Q

Diphyllobothrium latum

A

Can cause b12 deficiency

165
Q

Subacute combined degeneration

A

Degeneration of the dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts due to abnormal myelin
association with B12 deficiency

166
Q

How could you distinguish B12 from folate deficiency?

A

Methymalonic acid increases with B12 but not with THF deficiency

Homocystine increases with both

167
Q

Functions of Vitamin C?

A
  • Facilitates iron absorption
  • necessary for dopamine beta hydroxylase (dopamine to NE)
  • hydroxylation of proline and lysine in collagen synthesis
168
Q

Swollen gums, bruising, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, corkscrew hair

A

Vitamin C deficiency, scurvey

169
Q

Nausea, vomiting, diarrhea, fatigue, calcium oxalate nephrolithiasis, increased risk of iron toxicity in certain ppl

A

Vitamin C excess

170
Q

D2

A

Ergocalciferol - ingested from plants

171
Q

D3

A

Cholecalciferol consumed in milk and sun-exposed skin

172
Q

25-OH D3

A

Storage form

173
Q

1,25-OH2 D3

A

Calcitriol, active form

174
Q

Bone pain and deformity, muscle weakness, hypocalcemic tetany

A

Rickets, vitamin D deficiency

175
Q

What vitamin should you give a breastfed infant?

A

D

176
Q

Hypercalcemia, hypercalciuria, loss of appetite, stupor

A

Vitamin D excess

177
Q

When do you see vitamin D excess?

A

Sarcoidosis - increased activation of vit D by epithelioid macrophages

178
Q

Hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination

A

Vitamin E / tocopherol deficiency

179
Q

Tocopherol

A

Vitamin E

180
Q

What does vitamin E do?

A

Antoxident - protects erythrocytes and membranes from free radical damage.

181
Q

What vitamin should you inject at birth?

A

Vitamin K

182
Q

Neonatal hemorrhage with increased PT and PTT but normal bleeding time.

A

Vitamin K deficiency.

183
Q

What does Vitamin K do?

A

Cofactor for gamma carboxylation of glutamic acid residues on various proteins

184
Q

Delayed wound healing, hypogonadism, decreased adult hair (axillary, facial, pubic), dysgeusia, anosmia, acrodermatitis enteropathica, alcoholic cirrhosis

A

Zinc deficiency

185
Q

Kwashiorkor

A

Malnutrition
Edema
Anemia
Fatty Liver

Protein deficiency

186
Q

Marasmus

A

Total calorie malnutrition resulting in tissue and muscle wasting, loss of subcutaneous fat, and variable edema.

187
Q

Fomepizole

A

Inhibits alcohol dehydrogenase

188
Q

Disulfiram

A

inhibits acetaldehyde dehydrogenase

189
Q

Phosphorylase

A

Adds inorganic phosphate onto substrate without using ATP

190
Q

Dehydrogenase

A

Catalyzes REDOX reactions

191
Q

What takes place in both mitochondria and cytoplasm?

A

Heme synthesis, urea cycle, gluconeogenesis

HUGS take 2

192
Q

Rate determining enzyme of glycolysis

A

PFK-1
AMP+, F26bisphospate+
ATP-, Citrate -
Frump Cat at JFK

193
Q

Gluconeogenesis rate determining enzyme

A

Fructose 1,6 bisphosphatase
Citrate +
AMP-, fructose 2,6 bisphosphate -
Sit the frump

194
Q

TCA cycle rate determining enzyme

A

Isocitrate dehydrogenase
ADP+
ATP-, NADH-
Add ice to Nat

195
Q

Glycogenesis rate determining enzyme

A

Glycogen synthase
Glucose 6 phosphate+, insuline +, cortisol +
Epinephrine -, glucagon-
Glue in court | glues epic gentleman

196
Q

Glycogenolysis

A

Glycogen phosphorylase
Epinephrine+, glucagon+, AMP+
Glucose-6-phosphate-, insulin-, ATP-
Epic glue in the ampitheater glues insurers atrociously

197
Q

HMP shunt

A

Glucose 6 phosphate dehydrogenase - G6PD
NADP+
NADPH-
HMph, nope, nope

198
Q

De novo pyrimidine synthesis

A

Carbamoyl phosphate synthetase II

199
Q

De novo purine synthesis

A 
Glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase
AMP-, IMP-, GMP-
200
Q

Urea cycle

A

Carbamoyl phosphate synthetase I

N acetylglutamate+

201
Q

Fatty acid synthesis

A

Acetyl-Coa carboxylase (ACC) - turns acetyl coa into malonyl coa
Insulin+, citrate+
Glucagon-, palmitoyl coa-
Inside the fat citrus there was a newly synthesized glue palace

202
Q

Fatty acid oxidation

A

Carnitine acyltransferase I
Malonyl coa-
Mal gets a fat new car

203
Q

Ketogenesis

A

HMG-coa synthase

204
Q

Cholesterol synthesis

A

HMG coA reductase
Insulin+, thyroxine+
Glucagon-, cholesterol-
In thy cold glum home we burned coal.

USMLE GAME TIME (46 decks)

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