Easy Biochem Flashcards

1
Q

amino acids in histones

A

lysine and arginine (positive)

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2
Q

H1

A

binds to nucleosome and linker DNA to stabilize chromatin fiber

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3
Q

heterochromatin

A

condensed, methylated, Barr bodies are examples

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4
Q

euchromatin

A

less condensed, transcriptionally active, sterically accessible

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5
Q

methyaltion

A

occurs on C and A leading to decrease in transcription

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6
Q

histone actyelation

A

relaxes coiling, allows fro transcription

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7
Q

amino acids necessary for dna synthesis

A

GAG
glycine
aspartate
glutamine

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8
Q

characteristics of protomer regions

A

AT rich (TATA box)

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9
Q

helicase

A

unwinds DNA

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10
Q

single stranded binding proteins

A

prevents strand from rejoining

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11
Q

DNA topoismoerases

A

single stranded nicks to prevent supercoiling

  • irinotecan/topotecan = topo 1
  • etoposide/teniposide = topo 2
  • fluoroquinolones = topo 2 in prokaryotes
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12
Q

primase

A

makes RNA primer

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13
Q

DNA pol III

A

only in prokaryotes, 3-5 proofreading

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14
Q

DNA pol I

A

prokaryote only, degrades RNA primer, replaces with DNA

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15
Q

DNA ligase

A

joins okazaki fragments

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16
Q

telomerase

A

eukaryotes only, adds to 3’ end, dysregulated in cancer

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17
Q

silent mutation

A

amino acid doesn’t change (due to wobble)

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18
Q

missense mutation

A

one amino acid is changes

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19
Q

nonsense mutation

A

adds a stop codon (UAG, UAA, UGA)

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20
Q

frameshift mutation

A

puts sequence out of frame

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21
Q

splice site mutation

A

keeps intron in that would have been removed

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22
Q

nucleotide excision repair

A

endonucleases removed bases, DNA pol and ligase fix, occurs in G1
- defective and xeroderma pigmentosa

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23
Q

base excision repair

A
  • glycosylase remove base creating AP site
  • AP endonuclease cleaves 5’ end
  • lyase cleaves 3’ end
  • DNA pol fills gap and ligase seals
  • important in spontaneous deamination
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24
Q

mismatch repair

A

occurs in G2

- defective in Lynch sydnrome

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25
Q

nonhomologous end joining

A
  • for double stranded breaks

- defective in ataxia telangiectasia, BRCA1 and Fanconi aemia

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26
Q

start codon

A

AUG

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27
Q

stop codons

A

UAG, UAA, UAG

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28
Q

AATAAA

A

polyadenylation signal in terminal exon

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29
Q

promoter

A

site where RNA pol II binds

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30
Q

RNA pol I

A

makes rRNA, most numberous

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31
Q

RNA pol II

A

makes mRNA, largest

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32
Q

RNA pol III

A

makes tRNA, smallest

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33
Q

alpha amanitin

A

in mushroom caps, inhibits RNA pol II

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34
Q

rifampin inhibits DAN dependent RNA polymerase

A

inhibits DNA dependent RNA polymerase in prokaryotes

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35
Q

mRNA processing by compartment

A
  • heterogeneous nuclear RNA gets 5’ cap, poly A tail and splicing of introns in nucleus
  • mRNA is translated in cytosol
  • mRNA quality control includes exonuclease, decapping enzymes and microRNAs
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36
Q

snRNPs

A

used for mRNA splicing

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37
Q

introns vs exons

A

introns - junk
exons - coding

*abnormal splicing = thalessemia

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38
Q

microRNAs

A

regulate gene expression by targeting 3’ untranslated region for degradation
- implicated in cancer

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39
Q

CCA

A

3’ end of tRNA - carries amino acid

40
Q

t-arm

A

of tRNA, tethers to ribosome

41
Q

D-arm

A

of tRNA, detects tRNA by aminoacyl-tRNA synthetase

42
Q

energy step in tRNA

A

use ATP to add amino acid to tRNA (aminoacyl-tRNA synthetase) *activation

43
Q

steps of protein synthesis

A
  1. initiation - GTP hydrolysis, IFs assemble 40S subunit
  2. elongation - binds to A site, rRNA catalyzes peptide bond, transfers, moves to P site
  3. termination - stop codon recognized by release factor and polypeptide is released
44
Q

chaperone protein

A

involved in protein folding

45
Q

cyclin dependent kinases

A

constitutive and inactive

46
Q

cyclins

A

control cell cycle, phase specific, activate CDKs

47
Q

cyclin - CDK complexes

A

phosphorylate proteins to progress cell cycle

48
Q

p53

A
  • inhibits CDK
  • hyperphosphorylation of Rb
  • inhibition of G1-S progression
49
Q

types of cells

A

permanent
labile
stable

50
Q

RER

A
  • secretory proteins
  • Nissl bodies synthesize neurotransmitters
  • free ribosomes are for cytosolic protines
51
Q

SER

A
  • site of steroid synthesis and detoxification
52
Q

mannose-6-phosphate

A

for lysosomal trafficking

53
Q

signal recognition particle

A

traffics proteins from ribosome to RER

54
Q

COPI

A

golgi - golgi (retrograde) - ER

55
Q

COPII

A

ER - cis Golgi (two steps forward, one step back)

56
Q

clathrin

A

trans Golgi - lysosomes, plasma membrane - endosomes (receptor mediated endocytosis)

57
Q

peroxisome

A
  • catabolism of very long chain fatty acids, branched chain, amino acids and ethanol
58
Q

peroxisomal disease

A

Zellweger syndrome and Refsum disease

59
Q

proteasom

A

degrades damaged or ubiquitin proteins

- problems in some cases of Parkinsons

60
Q

microfilaments

A

for muscle contraction and cytokinesis (Actin and microvilli)

61
Q

intermediate filaments

A

maintain cell sturcture

62
Q

microtubules

A

movement and cell division (cilia, flagella, mitotic spindle, centrioles)

63
Q

vimentin

A

intermediate filament in mesenchymal tissue

64
Q

desmin

A

intermediate filament in muscle

65
Q

GFAP

A

intermediate filament in neuroglia

66
Q

dyenin

A

retrograde transport

67
Q

kinesin

A

anterograde transport

68
Q

kartagener’s syndrome

A

problem with dynein arm

- causes situs inversus, male and female fertility problems, hearing loss, ectopic pregnancy

69
Q

type I collagen is made by

A

osteoblasts, in skin, tendons and bone

70
Q

type II collagen

A

cartilage, vitreous body, nucleus pulposus

71
Q

type III collagen

A

reticulin, skin blood vessels, uterus, fetal tissue, granulation tissue,

72
Q

defect in Ehlers Danlos

A

type III collagen

73
Q

type 4 collagen

A

basement membrane, defect in Alports and Goodpastures

74
Q

collagen synthesis steps

A
  1. synthesis - glycine proline and lysine
  2. hydroxylation - requires vitamin C
  3. glycosylation - hydrogen and disulfide bonds
  4. exocytosis - into extracellular space
  5. proteolytic processing - forms tropocollagen
  6. cross linking - using copper lysyl oxidase
75
Q

osetogenesis imperfecta

A
  • type I collagen disorder
  • autosomal dominant
  • blue sclera
  • affects bones, eye, teeth and ears
76
Q

Ehlers Danlos

A
  • poor collagen synthesis
77
Q

Menkes disease

A
  • impaired copper absorption
  • less activity of lysyl oxidase
  • brittle hair, growth retardation, hypotonia
78
Q

elastin

A
  • rich in non hydroxylated proline, lysine and glycine

- broken down by elastase

79
Q

marfan

A

defect in fibrillin

  • autosomal dominant
  • medial necrosis of media
  • floppy mitral valve
  • aneurysms
  • subluxation of lenses
80
Q

cre-lox

A

can inducibly manipulate genes at specific developmental points (to study a gene whose deletion causes embryonic death)

81
Q

RNA interference

A

dsRNA blocks mRNA, blocks expression

82
Q

pleiotropy

A

one gene contributes to multiple phenotype effects

83
Q

dominant negative mutation

A
  • nonfunctional protein prevents another product from working
  • dominant
84
Q

linkage disequilibirum

A

measured in a population

- two alleles occur together frequently

85
Q

McCune Albright syndrome

A
  • mutation in G protein signaling
  • unilateral cafe au lait with ragged edges, polyostotic fibrous dysplasia, endocrinopathy
  • mosaic
86
Q

gonadal mosaicism

A

suspected in parents and relatives do not have a disease

87
Q

allelic heterogeneity

A

different mutations in the sam locus produce the same phenotype (thalassemia)

88
Q

heteroplasmy

A

variable expression in mitochondria disorders

89
Q

Prader-Willi

A

maternal is normally silent, paternal is deleted

90
Q

Anglemanns

A

maternal gene is delected

91
Q

capitation

A

fixed fee for all services for a patient

92
Q

defect in nonhomologous end joining

A

ataxia telangiectasia, BRCA1 and Fanconi anemia

93
Q

P bodies

A

maintain RNA in the cytosol

94
Q

anti-Smith antibodies

A

in lupus, anti-snRNPs

95
Q

anti-U1 antibodies

A

mixed connective tissue disease