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0. Step Ia > Biochem - molecular, genes, lipids > Flashcards

Biochem - molecular, genes, lipids Flashcards

1
Q

excess ATP, dATP, decreased lymphocyte count

A

ADA (adenosine deaminase deficiency), AR mutation

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2
Q

SCID

A

ADA (adenosine deaminase deficiency), AR mutation

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3
Q

3 mo boy with delayed motor development, develops dystonia. 2 years later exhibits compulsive nail biting and banging head against wall. Develops renal failure and arthritis.

A

Lesch-Nyhan Syndrome - mutation in HGPRT

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4
Q

excess uric acid + adenine + guanines

A

Lesch-Nyhan Syndrome - mutation in HGPRT (converts hypoxanthine to IMP and guanine to GMP

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5
Q

HGPRT stands for:

A 
HGPRT:
Hyperuricemia
Gout
Pissed off (aggression, self-mutilation) Retardation (intellectual disability)
DysTonia
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6
Q

trmt for excess uric acid + adenine + guanines?

A

allopurinol or febuxostat (2nd line)

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7
Q

degenerate codon definition

A

most a.a. are encoded by multiple codons

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8
Q

unambiguous codon definition

A

each codon specifies 1 a.a.

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9
Q

commaless codon definition

A

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

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10
Q

universal codon definition (exception to this?)

A

genetic code is conserved throughout evolution

exception in humans: mitochondria

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11
Q

difference btwn DNA pol I and III

A

Pol III - 5’->3’ synthesis, proofreads with 3’->5’ exonuclease, LEADING + LAGGING strand

Pol I - same fxn as pol III, but can also excise RNA primer with 5’->3’ exonuclease, LAGGING strand only

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12
Q

Rx that inhibits DNA topoisomerase in prokaryotes

A

fluoroquinolones

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13
Q

leading strand orientation?

lagging strand orientation?

A

leading: 3’ –> 5’
lagging: 5’ –> 3’

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14
Q

difference between transition and transversion

A

Transition - change within the same class

Transversion - change to a different class

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15
Q

Nonsense mutation

A

Nucleotide substitution resulting in early stop codon.

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16
Q

Missense mutation

A

Nucleotide substitution resulting in changed amino acid (conservative if new amino acid is similar in chemical structure).

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17
Q

disease with defective nucleotide excision repair

A

xeroderma pigmentosum, AR

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18
Q

disease with defective mismatch repair

A

HNPCC

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19
Q

disease with defective non-homologous end joining

A

ataxia telangiectasia

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20
Q

how is DNA and RNA template read and synthesized during transcription/translation?

A

DNA: 3 –> 5 (synthesized 5’–>3’)

mRNA: 5 –> 3 (synthesized N–C terminus)

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21
Q

mRNA stop codons?

A 
UGA = U Go Away. 
UAA = U Are Away.
UAG = U Are Gone.
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22
Q

where is the TATA box located?

A

promoter region

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23
Q

3 types of eukaryotic RNA polymerase

A

I - rRNA (most numerous; “Rampant”)
II - mRNA (largest, “Massive”)
III - tRNA (smallest, “Tiny”)

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24
Q

types of prokaryotic RNA polymerase

A

1 RNA polymerase, but makes all 3 (rRNA, mRNA, tRNA)

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25
Q

polyadenylation signal

A

AAUAA

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26
Q

P bodies

A

distinct foci in cytoplasm of eukaryotic cell - contains enzymes involved in mRNA turnover:

  • decap and degrade unwanted mRNAs
  • store mRNA until needed
  • repress translation via miRNAs (related to siRNAs)
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27
Q

hnRNA

A

precursor to mRNA. undergoes processing in the nucleus:

  • 5’ cap
  • 3’ polyadenylation
  • splicing out introns
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28
Q

snRNPs are found in? associated disease?

A

found in spliceosome (in nucleus, where pre-mRNA is cleaved form mRNA)

associated dz: SLE - contains anti-Smith antibodies against spliceosomal snRNPs

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29
Q

snRNPs are found in? associated disease?

A

found in spliceosome (in nucleus, where pre-mRNA is cleaved form mRNA)

associated dz: MCTD - contains anti-U1 RNP antibodies against spliceosomal snRNPs

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30
Q

what accounts for the degeneracy of genetic code?

A

tRNA wobble - accurate base pairing is required only in the first 2 nucleotide positions of an mRNA codon. Codons differing in the 3rd “wobble” position may code for the same tRNA/amino acid

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31
Q

What initiates mRNA translation?

A

GTP hydrolysis

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32
Q

Eukaryotic ribosomes

A

40S + 60S –> 80S (Even)

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33
Q

prokaryotic ribosomes

A

30S + 50S –> 70S (Odd)

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34
Q

what normally inhibits G1-to-S progression?

A

p53 and hypophosphorylated Rb

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35
Q

Neurons, skeletal and cardiac muscle, RBCs are considered to be what type of cells relative to the cell cycle?

A

permanent - remain in G0, regenerate from stem cells

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36
Q

Hepatocytes, lymphocytes are considered to be what type of cells relative to the cell cycle?

A

Stable (quiescent) - enter G1 from G0 when stimulated.

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37
Q

Bone marrow, gut epithelium, skin, hair follicles, germ cells are considered to be what type of cells relative to the cell cycle?

A

labile - never go to G0, divide rapidly with a short G1. Most affected by chemotherapy.

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38
Q

Nissl bodies?

A

found in RER in neurons- makes NTs for secretion

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39
Q

RER makes…

most abundant in…

A

secreted proteins

abundant in goblet cells of small intestines, plasma cells

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40
Q

SER makes…

most abundant in…

A

steroids and detoxes drugs and poisons

abundant in hepatocytes, adrenal cortex, gonads

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41
Q

residue added to proteins for trafficking to lysosomes

implicated in what disease

A

mannose-6-phosphate

I-cell disease (inclusion cell disease) - failure of the Golgi to phosphorylate mannose residues

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42
Q

patient with elevated serum proteases, glycosylases, lipases, hydrolases

A

I-cell disease (inclusion cell disease) - failure of the Golgi to phosphorylate mannose residues

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43
Q

I-cell disease (inclusion cell disease) features

A 
coarse facial features
clouded corneas
restricted joint movement (claw shaped hands)
high plasma levels of lysosomal enzymes
Often fatal in childhood
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44
Q

Signal recognition particle (SRP)

A

cytosolic ribonucleoprotein that traffics proteins from the ribosome –> RER.

Absent or dysfunctional SRP –> proteins accumulate in the cytosol.

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45
Q

COPI

A

RETROgrade trafficking

Golgi –> Golgi; Golgi –> ER.

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46
Q

COPII

A

ANTEgrade trafficking

Golgi –> Golgi; ER –> Golgi.

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47
Q

misfolded proteins in the RER are destined for..?

A

polyubiquinated and targeted by proteasomes

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48
Q

centriole configuration + function

A

centrioles (9x3)

two pairs form one centrisome

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49
Q

basal body configuration + function

A

9x3 (+2) nucleation site for growth of axoneme microtubules

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50
Q

centrisome configuration + function

A 
2 centrioles (9x3)
serves as anchoring sites for proteins that anchor microtubules
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51
Q

cilia structure

A

9 + 2 (forms motile cilia; many projections)

9 + 0 (forms motile cilia; forms one projection from cell)

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52
Q

where is 9 + 0 microtubule configuration usually found?

A

non-motile (1˚ cilia) - serve as a sensory receptor on primitive node cells to establish R/L axis of body

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53
Q

situs inversus

A

congenital condition in which the major visceral organs are reversed or mirrored from their normal positions - dextrocardia on CXR

due to primary ciliary dyskinesia

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54
Q

situs inversus, chronic sinusitis, and bronchiectasis

A

Kartagener syndrome - immotile cilia prevents removal of mucus/pathogens from sinuses and respiratory tract

often have ectopic pregnancies or immobile sperm as well

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55
Q

Kartagener syndrome etiology

A

1° ciliary dyskinesia - immotile cilia due to a dynein arm defect

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56
Q

Drugs that affect microtubules

A

Microtubules Get Constructed Very Poorly):

  • Mebendazole (anti-helminthic)
  • Griseofulvin (anti-fungal)
  • Colchicine (anti-gout)
  • Vincristine/Vinblastine (anti-cancer)
  • Paclitaxel (anti-cancer)
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57
Q

Ouabain MoA

A

binding to K+ site on Na/K ATPase

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58
Q

Cardiac glycosides

A

digoxin and digitoxin

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59
Q

digoxin and digitoxin MoA

A

directly inhibit the Na/K ATPase; leads to indirect inhibition of Na+/ Ca2+ exchange –> increase [Ca2+]i –> increase cardiac contractility.

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60
Q

Collagen Type I

associated dz?

A

Bone, Skin, Tendon, Dentin, Fascia, CORNEA, SCAR TISSUE

Osteogenica Imperfecta

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61
Q

Collagen Type II

A

cartilage, vitreous body, nucleus pulposus

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62
Q

Collagen Type III

A

Reticulin - BV, Skin, Uterus, Fetal tissue, GRANULATION tissue

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63
Q

Collagen Type IV

associated dz?

A

Basement membrane (“four” = “floor”), basal lamina, LENS

Alport Syndrome - defect in synthesis
Goodpasture Syndrome - ab attack

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64
Q

Vimentin stain

A

Connective tissue

“Men like to connect tissues”

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65
Q

Desmin

A

muscle (desMin)

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66
Q

GFAP

A

neuroglia

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67
Q

cytokeratin

A

epithelial cells

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68
Q

neurofilaments

A

neurons

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69
Q

proline + lysine should make you think of

A

preprocollagen

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70
Q

vitamin c is required for what? deficiency results in

A

hydroxylation of proline+lysine residues on collagen. Deficiency –> scurvy

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71
Q

triple helix of 3 collagen a chains is called this:

where is it formed?

deficiency results in:

A

pro-collagen, formed in RER

deficiency: osteogensis imperfecta

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72
Q

defect in cross-linking of tropocollagen molecules to form collagen FIBRILS

where does this cross-linking process normally occur? What d/o do you see this in?

A

extracellular (outside fibroblasts)

Ehler-Danlos

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73
Q

decrease in production of normal type I collagen

sx?

A

Osteogenica imperfecta; autosomoal dominant

  • factures
  • blue sclerae
  • hearing loss
  • dental imperfections
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74
Q

ehlers-danlos syndrome - classical type

A

type V collagen deficiency; joint + skin sx (hyperextensible skin, hypermobile joints)

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75
Q

ehlers-danlos syndrome - vascular type

A

type III collagen deficiency: vascular (berry/aortic aneurysms) and organ rupture

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76
Q

patient w/ brittle, kinky hair, growth retardation, and hypotonia

A

Menkes disease - CT dz caused by impaired Cu absorption and transport (Cu is required for LYSYL OXIDASE to cross-link extracellular tropocollagen into collagen fibrils)

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77
Q

mutation in a glycoprotein that forms a sheath around elastin

A

Marfan syndrome - defect in fibrillin

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78
Q

deficiency in this enzyme that results in excess elastase activity.

patients should avoid this:

A

A1AT deficiency (emphysema)

must avoid smoking

79
Q

what normally inhibits elastase?

mutation results in..?

A

A1AT

mutation: emphysema

80
Q

northern blot

A

RNA

81
Q

south-western blot

A

DNA binding proteins (TFs) - using labeled oligonucleotide probes

82
Q

Indirect elisa

A

uses a test antigen to see if a specific antibody is present in the patient’s blood

83
Q

direct elisa

A

uses a test antibody to see if a specific antigen is present in the patient’s blood

84
Q

sensitivity/specificity of elisa?

A

both approaches 100

85
Q

FISH

A

fluorescence in situ hybridization - RNA/DNA probe to localize specific genes on chromsomes

86
Q

type of nuclei acid used in cloning

A

mRNA

1) Expose mRNA to RT –> cDNA (no introns).
2) Insert cDNA fragments into bacterial plasmids w. antibiotic resistance genes.
3) Transform recombinant plasmid into bacteria.
4) . Surviving bacteria on antibiotic medium produce cDNA

87
Q

dsRNA

A

RNAi (complementary to a mRNA sequence of interest; promotes degradation of target mRNA)

88
Q

karyotyping uses what type of chromosomes?

A

metaphase chromsoomes

89
Q

Codominance

example?

A

Both alleles contribute to the phenotype of the heterozygote.

Blood groups A, B, AB
α1-antitrypsin deficiency

90
Q

Variable expressivity

example?

A

Phenotype varies among individuals with same genotype.

2 patients with NF1 may have varying disease severity.

91
Q

Incomplete penetrance

example?

A

Not all individuals with a mutant genotype show the mutant phenotype.

BRCA1 mutation does not always result in breast/ovarian cancer

92
Q

Pleiotropy

example?

A

One gene => multiple phenotypic effects

Untreated phenylketonuria (PKU) => light skin, intellectual disability, and musty body odor.

93
Q

Anticipation

example?

A

Increased severity / earlier onset of disease in succeeding generations.

Trinucleotide repeat diseases (e.g., Huntington disease).

94
Q

Loss of heterozygosity

example?

A

If a patient inherits or develops a mutation in a tumor suppressor gene, the complementary allele must be deleted/mutated before cancer develops. This is not true of oncogenes.

Retinoblastoma and the “two-hit hypothesis.”

95
Q

Dominant negative mutation

A

heterozygote produces a nonfunctional altered protein that also prevents the normal gene product from functioning.

96
Q

Linkage disequilibrium

A

certain alleles at 2 linked loci to occur together more often than expected by chance. Measured in a population

97
Q

Mosaicism

example?

A

genetically distinct cell lines in the same individual that arises from mitotic errors after fertilization; can be somatic vs gonadal

McCune-Albright syndrome = lethal if somatic; survivable if mosaic.

98
Q

somatic mosaicism

gonadal mosaicism

example?

A

Somatic mosaicism—mutation propagates through multiple tissues or organs.
Gonadal mosaicism—mutation only in egg or sperm cells.

McCune-Albright syndrome = lethal if somatic; survivable if mosaic

99
Q

Locus heterogeneity

Allelic heterogeneity

A

locus = mutations at different loci can produce a similar phenotype (Albinism)

Allelic = different mutations in the same locus produce the same phenotype (β-thalassemia)

100
Q

Heteroplasmy

A

Presence of both normal and mutated mtDNA, resulting in variable expression in mitochondrial inherited disease.

101
Q

Uniparental disomy

A

Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent; EUPLOID

compare heterodisomy vs isodisomy

102
Q

heterodisomy vs isodisomy

A

Heterodisomy (heterozygous) = meiosis I error.

Isodisomy (homozygous) = meiosis II error or postzygotic chromosomal duplication of one of a pair of chromosomes, and loss of the other of the original pair.

103
Q

Hardy-Weinberg population genetics eqns

A

p^2 + 2pq + q^2 = 1 and p + q = 1, which implies that:
p2 = frequency of homozygosity for allele p q2 = frequency of homozygosity for allele q 2pq = frequency of heterozygosity

104
Q

carrier frequency, if an autosomal recessive disease

A

2pq (hardy weinberg)

105
Q

frequency of an X-linked recessive disease in males? females?

A

males = q and in females = q^2

106
Q

hyperphagia, obesity, intellectual disability, hypogonadism, and hypotonia.

A

Prader-Willi syndrome

107
Q

gene from mom is normally silent and paternal gene is deleted/ mutated

A

Prader-Willi syndrome

108
Q

inappropriate laughter (“happy puppet”), seizures, ataxia, and severe intellectual disability.

A

AngelMan syndrome

109
Q

gene from dad is normally silent and Maternal gene is deleted/mutated.

A

AngelMan syndrome

110
Q

predict inheritance: many generations, both male and female, affected

A

Autosomal dominant

111
Q

predict inheritance: 25% of offspring from 2 carrier parents are affected; usually seen in only 1 generation

A

Autosomal recessive

112
Q

predict inheritance: sons of heterozygous mothers have a 50% chance of being affected. No male-to-male transmission

A

X-linked recessive

113
Q

Transmitted through both parents. Mothers transmit to 50% of daughters and sons; fathers transmit to all daughters but no sons.

A

X-linked dominant

114
Q

Transmitted only through the mother. All offspring of affected females may show signs of disease.

A

Mitochondrial inheritance

115
Q

chromosome mutation in ADPKD

A

16 - PKD1, 4 - PKD2 “16 letters in polycystic kidney”

116
Q

chromosome mutation in FAP

A

5 - APC gene “5 words in polyp”

117
Q

mutation in familial hypercholesterolemia

A

defective or absent LDL receptor; Elevated LDL, severe atherosclerotic disease early in life, and tendon xanthomas (classically in the Achilles tendon)

118
Q

mutation in Hereditary hemorrhagic telangiectasia

A

d/o of blood vessels; telangiectasia, recurrent epistaxis, skin discolorations, AVMs, GI bleeding, hematuria.

119
Q

mutation in Hereditary spherocytosis

A

spectrin or ankyrin defect; hemolytic anemia; increased MCHC. Treatment: splenectomy.

120
Q

chromosome mutation in Huntington disease

A

4 - CAG trinucleotide repeat (anticipation); depression, progressive dementia, choreiform movements, caudate atrophy, and decrease levels of GABA and ACh in the brain.

121
Q

mutation in Marfan’s

A

Fibrillin-1 gene; tall with long extremities, pectus excavatum, hypermobile joints, and long, tapering fingers and toes (arachnodactyly); cystic medial necrosis of aorta

122
Q

mutation in Multiple endocrine neoplasias (MEN)

A

MEN 2A and 2B are associated with ret gene.

123
Q

chromosome mutation in NF1

A

17 - autosomal dominant; 100% penetrance with variable expression; café-au-lait spots and cutaneous neurofibromas.

124
Q

chromosome mutation in NF2

A

22 - bilateral acoustic schwannomas, juvenile cataracts, meningiomas, and ependymomas

125
Q

chromosome mutation in tuberous sclerosis

A

numerous benign hamartomas; incomplete penetrance, variable expression

126
Q

chromosome mutation in von Hippel-Lindau disease

A

3 - VHL gene; development of numerous tumors

127
Q

chromosome mutation in Cystic fibrosis

A

chromosome 7 - ATP-gated Cl- channel; mutation causes proteins to be retained in the RER (not transported to the cell membrane)

= secretes Cl− in lungs and GI tract
= reabsorbs Cl− in sweat glands

128
Q

Cystic fibrosis pathophysiology and diagnosis

A

= secretes Cl− in lungs and GI tract
= reabsorbs Cl− in sweat glands

dx: increase Cl- in sweat, contraction alkalosis and hypokalemia because of ECF H2O/Na+ losses and concomitant renal K+/H+ wasting

129
Q

Cystic fibrosis treatment

A

N-acetylcysteine = loosen mucus plugs (cleaves disulfide bonds within mucus glycoproteins)

Dornase alfa (DNAse) to clear leukocytic debris (mucolytic)

130
Q

Cystic fibrosis complications

A
  • Recurrent pulmonary infections (e.g., Pseudomonas)
  • chronic bronchitis and bronchiectasis
  • Reticulonodular pattern on CXR
  • pancreatic insufficiency, malabsorption and steatorrhea
  • nasal polyps
  • meconium ileus in newborns
  • Infertility in males (absence of vas deferens, absent sperm)
  • Fat-soluble vitamin deficiencies (A, D, E, K)
131
Q

chromosome mutation in Duchenne’s

A

X-linked frameshift mutation (dystrophin gene (DMD) has the longest coding
region of any human gene -> increases chance of spontaneous mutations)

132
Q

lab diagnosis of Duchenne’s

A

increase CPK and aldolase

WB and muscle biopsy to confirm

133
Q

Symptoms of Duchenne’s

A
  • weakness begins in pelvic girdle muscles and progresses superiorly
  • Pseudohypertrophy of calf muscles
  • Gower maneuver—patients use upper extremity to help them stand up
  • Onset before 5 years of age
  • Dilated cardiomyopathy is common cause of death.
134
Q

Becker’s

A

X-linked point mutation in dystrophin gene (no frameshift as in Duchenne’s)

135
Q

post- pubertal macroorchidism (enlarged testes), long face with a large jaw, large everted ears, autism, mitral valve prolapse.

A

Fragile X syndrome (trinucleotide repeat d/o)
X-linked affecting methylation patterns of FMR1 gene
(2nd most common cause of intellectual disability)

136
Q

chromsome mutation in Down syndrome

A

21

137
Q

chromsome mutation in Edward syndrome

A

18

138
Q

chromsome mutation in Patau syndrome

A

13

139
Q

increased nuchal translucency and hypoplastic nasal nasal bone
decreased serum PAPPA, increased ßhCG

A

1st trimester Down Syndrome

140
Q

low AFP, estriol

increase hCG, inhibin

A

2nd trimester Down Syndrome

141
Q

increased nuchal translucency and hypoplastic nasal nasal bone
decreased serum PAPPA, ßhCG

A

Edwards Syndrome (18) - first trimester

142
Q

low AFP, estriol, hCG, inhibin

A

Edwards Syndrome (18) - second trimester

143
Q

low β-hCG, PAPP-A

increased nuchal translucency

A

Patau Syndrome (13)

144
Q

evere intellectual disability, rocker- bottom feet, micrognathia (small jaw), low-set Ears, clenched hands, prominent occiput, congenital heart disease.
Death usually occurs within 1 year of birth.

A

Edwards syndrome (trisomy 18),

145
Q

Severe intellectual disability, rocker- bottom feet, microphthalmia, microcephaly, cleft liP/Palate, holoProsencephaly, Polydactyly, congenital heart disease.
Death usually occurs within 1 year of birth.

A

Patau syndrome (trisomy 13)

146
Q

intellectual disability, flat facies, prominent epicanthal folds, single palmar crease, gap between 1st 2 toes, duodenal atresia, Hirschsprung disease, congenital heart disease (most commonly ostium primum-type atrial septal defect [ASD]), Brushfield spots.

A

Down Syndrome (21)

147
Q

Associated with increase risk of ALL, AML, and Alzheimer disease (> 35 years old).

A

Down Syndrome

148
Q

these numbers make you think of…?

13, 14, 15, 21, and 22

A

Robertsonian translocation - these are acrocentric chromosomes (chromosomes with centromeres near their ends)

balanced translocations = no abnormal phenotype
Unbalanced translocations = miscarriage, stillbirth, and chromosomal imbalance (e.g., Down syndrome, Patau syndrome).

149
Q

microcephaly, moderate to

severe intellectual disability, high-pitched crying/mewing, epicanthal folds, cardiac abnormalities (VSD)

A

Cri du chat = cry of the cat

150
Q

chromsome abnormality in Cri-du-chat syndrome

A

5 - microdeletion of short arm

Cri du chat syndrome

151
Q

“elfin” facies, intellectual disability, hypercalcemia (increased sensitivity to vitamin D), well-developed verbal skills, extreme friendliness with strangers, cardiovascular problems.

A

7 - microdeletion of long arm (deleted region includes elastin gene)

Williams syndrome

152
Q

22q11 deletion

A 
DiGeorge Syndrome - thymic, parathyroid, and cardiac defects.
"CATCH-22"
Cleft palate
Abnormal facies
Thymic aplasia ->  T-cell deficiency
Cardiac defects
Hypocalcemia 2° to parathyroid aplasia
153
Q

thymus develops from which branchial pouches?

A

Due to aberrant development of 3rd and 4th branchial pouches

154
Q

main processes that go on after a fasting state?

A

Hepatic glycogenolysis (major)

hepatic gluconeogenesis, adipose release of FFA (minor).

Glucagon, adrenaline stimulate use of fuel reserves.

155
Q

main processes that go on during d1-3 of starvation?

A

Blood glucose maintained by:
hepatic glycogenolysis + gluconeogenesis
adipose release of FFA
muscle + liver shift fuel use from glucose -> FFA

156
Q

Hepatic gluconeogenesis relies on these things

A

peripheral tissue: lactate + alanine

adipose tissue: glycerol and propionyl- CoA (from odd-chain FFA—the only TG components that contribute to gluconeogenesis)

157
Q

main processes that go on after d3 of starvation?

A

Adipose stores (ketone bodies become the main source of energy for the brain)

After these are depleted, vital protein degradation accelerates, leading to organ failure and death.

158
Q

Rate-limiting step of cholesterol synthesis?

A

HMG-CoA

Statins competitively and reversibly inhibit HMG-CoA reductase.

159
Q

Pancreatic lipase

A

degradation of dietary triglycerides (TG) in small intestine.

160
Q

Lipoprotein lipase (LPL)

A

degradation of TG circulating in chylomicrons and VLDLs. Found on vascular endothelial surface.

161
Q

Hepatic TG lipase (HL)

A

degradation of TG remaining in IDL.

162
Q

Hormone-sensitive lipase

A

degradation of TG stored in adipocytes.

163
Q

LCAT

A

catalyzes esterification of cholesterol.

164
Q

Cholesterol ester transfer protein (CETP)

A

mediates transfer of cholesterol esters to other

lipoprotein particles.

165
Q

ApoE

A

Mediates chyloµ remnant uptake by LDL receptors on hepatocytes (liver uptake)

166
Q

ApoAI

A

Activates LCAT to esterify cholesterol on nascent HDL -> forms mature HDL

167
Q

ApoCII

A

activates Lipoprotein Lipase on peripheral cells to deliver TGs

168
Q

ApoB48

A

liver sends this out during the FED state to mediate chylo-µ transport from the gut into circulation (delivers dietary TG to peripheral tissues)

169
Q

ApoB100

A

packaged into VLDL particles that the liver sends out during the FASTING state to deliver cholesterol + FA to peripheral tissues

170
Q

chylomicron function? produced by?

A

1) delivers dietary TGs to peripheral tissue.
2) delivers cholesterol to liver in the form of chylomicron remnants, which are mostly depleted of their TGs.

3) Secreted by intestinal epithelial cells, packaged w/ ApoB48, ApoE, ApoCII and ApoCIII

171
Q

VLDL function? produced by?

A

packaged with ApoB100; delivers HEPATIC TGs to peripheral tissues during FASTING state

172
Q

IDL function? produced by?

A

Formed in the degradation of VLDL; delivers remaining TGs and cholesterol to liver.

173
Q

LDL function? produced by?

A

Delivers hepatic cholesterol to peripheral tissues. Formed by hepatic lipase modification of IDL in the peripheral tissue. Taken up by target cells via receptor-mediated endocytosis.

174
Q

HDL function? produced by?

A

Mediates reverse cholesterol transport from periphery to liver. Acts as a repository for ApoC and ApoE (which are needed for chylomicron and VLDL metabolism). Secreted from both liver and intestine. Alcohol increases synthesis.

175
Q

Type I hyper-chylomicronemia

  • pathophys?
  • increased blood levels of?
A

ø Lipoprotein lipase or altered Apo C-II (AR)

forms excess Chylomicrons, TG, cholesterol

176
Q

Type IIa—familial hyper- cholesterolemia

  • pathophys?
  • increased blood levels of?
A

ø LDL receptors (AD)

forms excess LDL, cholesterol

177
Q

IV—hyper- triglyceridemia

  • pathophys?
  • increased blood levels of?
A

Hepatic overproduction of VLDL (AD)

forms excess VLDL, TG

178
Q

familial dyslipidemia that causes

  • pancreatitis
  • hepatosplenomegaly
  • eruptive/pruritic xanthomas
A

Type I hyperchylomicronemia (no risk for atherosclerosis)

179
Q

familial dyslipidemia that causes

  • accelerated atherosclerosis (may have MI before 20)
  • tendon xanthomas
  • corneal arcus
A

Type IIa—familial hyper- cholesterolemia - LDL increases atheroma risk

180
Q

familial dyslipidemia that causes pancreatitis only

A

Type IV hyper- triglyceridemia

181
Q

Telomerase

A

RNA dependent DNA polymerase (in other words, reverse transcriptase) that adds DNA to 3’ end of chromosomes to avoid loss of genetic material w/ every dupliation

182
Q

what is common to ALL tRNAs (both eukaryotic and prokaryotic)?

A

CCA at 3’ end of tRNA; serves as a linker of the tRNA and the a.a.

183
Q

difference btwn T arm and D arm of tRNA

A

T arm = contains sequence for tRNA ribosome binding

D arm = contains dihydrouracil for tRNA recognition by the correct aminoacyl tRNA synthesis

184
Q

linker of a.a. and the proper tRNA

A

aminoacyl-tRNA synthetase (1 per a.a.; serves as a matchmaker) - serves as a match maker and is responsible for adding the right a.a. to the right tRNA.
tough job.

185
Q

collagen is comprised mostly of

A

glycine (followed by proline + lysine)

186
Q

how does Arsenic affect glycolysis?

physical presentation of this?

A

causes it to produce 0 net ATP because it inhibits lipoic acid, which is present in the pyruvate dehydrogenase complex as well as the a-ketoglutarate dehydrogenase complex

physical presentation: vomiting, rice water stool, and GARLIC breath…say what?

187
Q

gene mutation associated with Maturity-onset diabetes of the young (MODY)

A

Glucokinase

188
Q

essential a.a.?

A 
methionine
Valine
histidine
Isoleucine
Phenylalanine
Threonine
Tryptophan
Leucine
Lysine

PITT Essentially LIEd to LUCy about going to the MET with HIS ex VALerie

189
Q

dyslipidemias - which two particles are responsible for causing pancreatitis?

A

chyloµ + VLDL

190
Q

dyslipidemias - which two particles are responsible for causing fatty liver?

A

VLDL + IDL

191
Q

dyslipidemias - which two particles are responsible for causing pancreatitis?

A

LDL + lipo(a)

192
Q

what happens if hepatic lipase is mutated?

A

increased HDL - good mutation to have!

193
Q

what happens if ABCA1 is mutated?

A

ABCA1 functions to remove excess cholesterol + FFA from peripheral tissues

∆ ABCA1 = Tangier’s disease - severe reduction in HDL particles and accumulation of cholesterol in many body tissues

Presentation:

  • Tangier’s tonsils (extremely enlarged, orange/yellow)
  • premature atherosclerosis
  • slightly elevated amounts of fat in circulation
  • other signs
    - > enlarged spleen, liver
    - > clouding of cornea
    - > early onset of cardiovascular disease

0. Step Ia (28 decks)

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