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My step 1 mnemonics > Biochemistry - Molecular and Genetics > Flashcards

Biochemistry - Molecular and Genetics Flashcards

1
Q

Deamination reactions:

Cytosine

A

uracil

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2
Q

Deamination reactions:

Adenine

A

hypoxanthine

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3
Q

Deamination reactions:

Guanine

A

xanthine

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4
Q

Deamination reactions:

5-methylcytosine

A

thymine

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5
Q

Amino acids necessary for purine synthesis

A

Cats purr until they GAG:
Glycine
Aspartate
Glutamine

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6
Q

Defective purine salvage due to absent HGPRT results in:

A 
HGPRT:
Hyperuricemia
Gout
Pissed off (aggression, self-mutilation)
Retardation (intellectual disability)
DysTonia
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7
Q

Frameshift examples

A

Duchenne muscular dystrophy, Tay-Sachs disease.

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8
Q

Splice site examples

A

Examples include rare causes of cancers, dementia, epilepsy, some types of beta-thalassemia.
BCDE-splice

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9
Q

Lac-operon:

Low glucose ->

A

inc. adenylate cyclase activity -> inc. generation of cAMP from ATP - activation of
catabolite activator protein (CAP) - inc. transcription.

No glucose CAP stays on!
glucose makes you take off your hat!

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10
Q

Lac-operon:

High lactose -

A

unbind repressor protein from repressor/operator site - inc. transcription.

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11
Q

Nucleotide excision

repair

A

G1, Tide, XP, P-dimers

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12
Q

Base excision repair:

A

“GEL PLease Damm it throughout!:

Important in the repair of spontaneous/toxic
deamination.

Base-specific Glycosylase removes altered base
and creates AP site (apurinic/apyrimid inic).
One or more nucleotides are removed by
AP-Endonuclease, which cleaves the 5’ end.
Lyase cleaves the 3’ end. DNA Polymerase-beta
fills the gap and DNA Ligase seals it. Occurs
throughout cell cycle.

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13
Q

Homologous recombination

A

“Broken Fan” Defective in breast/ovarian cancers with BRCA1

mutation and in Fanconi anemia.

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14
Q

Poly-A polymerase does not require…

A

a template.

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15
Q

polyadenylation signal…

A

AAUAAA

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16
Q

mRNA quality control occurs at…

A

cytoplasmic processing bodies (P-bodies)

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17
Q

cytoplasmic processing bodies (P-bodies) contain…

A

exonucleases, decapping enzymes, and
microRNAs; mRNAs may be degraded or
stored in P-bodies for future translation.

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18
Q

RNA polymerase I makes

A

rRNA, the most common (rampant) type; present only in

nucleolus. Rishon

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19
Q

RNA polymerase II makes

A

mRNA (largest RNA, massive) and small nuclear RNA (snRNA). mRNA is read 5’ to 3’.
SheNi + Mishne

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20
Q

RNA polymerase III makes

A

tRNA
(smallest RNA, tiny).
“Three”

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21
Q

Variants in which splicing occurs abnormally are

implicated…

A

oncogenesis (cancer) and many genetic
d disorders (eg, beta-thalassemia, Gaucher disease,
Tay-Sachs disease, Marfan syndrome).
“splice - BC- MarTy Grah”

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22
Q

Covalent alterations

A

Phosphorylation, glycosylation, hydroxylation, methylation, acetylation, and ubiquitination.

HUG the MAP

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23
Q

Permanent cell

A

Neurons, skeletal and cardiac muscle, RBCs.

NaMeR

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24
Q

Stable (quiescent) cells

A

hepatocytes, lymphocytes, PCT (tubels), periosteal cells.

HeLPT

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25
Q

Labile cells

A

Bone marrow, gut epithelium, skin, hair follicles,

germ cells.

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26
Q

Rough endoplasmic

reticulum modification

A

N-linked oligosaccharide addition to

lysosomal and other proteins.

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27
Q

Cell trafficking Golgi

A

Modifies N-oligosaccharides on asparagine. Adds O-oligosaccharides on serine and threonine. Adds mannose-6-phosphate to proteins for trafficking to lysosomes.

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28
Q

Peroxisome

A

ABC(3)’S(3)

Membrane -enclosed organelle involved in:
• beta-oxidation of very-long-chain fatty acids (VLCFA)
• alfa-oxidation (strictly peroxisomal process)
• Catabolism of branched-chain fatty acids, amino acids, and ethanol
• Synthesis of cholesterol, bile acids, and plasmalogens (important membrane phospholipid,
especially in the white matter of the brain)

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29
Q

Zellweger syndrome

A

autosomal recessive disorder of peroxisome biogenesis due to mutated PEX genes. Hypotonia, seizures, hepatomegaly, early death.

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30
Q

Refsum disease

A

“Refuse to SCATE, Payton not a priest”
autosomal recessive disorder of alfa-oxidation - Phytanic acid not metabolized to pristanic acid. Scaly skin, ataxia, cataracts/night blindness, shortening of 4th toe, epiphyseal
dysplasia. Treatment: diet, plasmapheresis.

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31
Q

Adrenoleukodystrophy

A

easy as ABCD1 x)
X-linked recessive disorder of beta-oxidation due to mutation in ABCD1
gene - VLCFA buildup in adrenal glands, white (leuko} matter of the brain, testes. A progressive disease that can lead to adrenal gland crisis, coma, and death.

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32
Q

Collagen Type I

A 
Most common (90%) - Bone (made by osteoblasts), Skin, Tendon, dentin, fascia, cornea, late wound repair.
BoWne DeFeCTS
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33
Q

Collagen Type II

A

Cartilage (including hyaline), vitreous body,

nucleus pulposus.

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34
Q

Collagen Type III

A

Reticulin- skin, blood vessels, uterus, fetal
tissue, granulation tissue.
Fuck VaGUS!

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35
Q

Collagen Type IV

A 
Basement membrane (basal lamina), lens.
BasaL
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36
Q

Collagen synthesis

A

Synthesis-Hydroxylation-Glycosylation-Exocytosis-Proteolytic processing-Cross-linking
“Seems Having Good Ends People Crosslinks”

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37
Q

Elastin

A

The stretchy protein within the Skin, Lungs, large Arteries, Elastic ligaments, Vocal cords, ligament Flava (connect vertebrae - relaxed and stretched conformations).

Rich in nonhydroxylated proline, glycine, and lysine residues, vs the hydroxylated residues of collagen.

SLAVE Flava is not hydroxilated

38
Q

AngelMan syndrome gene

A

UBE3A gene is silenced

39
Q

Autosomal dominant diseases

A

STAFFMMANN-HTML-V:
Achondroplasia, ADPKD, FAP, Familial hypercholesterolemia, hereditary hemorrhagic Telangiectasia (Osler-Weber-Rendu
syndrome), hereditary Spherocytosis, Huntington disease, Li-Fraumeni syndrome, Marfan syndrome,
MEN, Myotonic muscular dystrophy, Neurofibromatosis type I (von
Recklinghausen disease), Neurofibromatosis type 2, Tuberous sclerosis, Von Hippel-Lindau disease.

40
Q

Cystic fibrosis Tx:

A

A-SPAID

Multifactorial: chest Physiotherapy, Albuterol, aerosolized Dornase alfa (DNase), and hypertonic Saline facilitates mucus clearance. Azithromycin used as an anti-inflammatory agent. Ibuprofen slows disease progression.
In patients with Phe508 deletion: a combination of lumacaftor (corrects misfolded proteins and improves
their transport to the cell surface) and ivacaftor (opens Cl- channels - improved chloride transport).

41
Q

X-linked recessive

disorders

A

BLOOD High WiFi:

Ornithine transcarbamylase deficiency, Fabry disease, Wiskott-Aldrich syndrome, Ocular albinism, C 6PD deficiency, Hunter syndrome, Bruton agammaglobulinemia, Hemophilia A and B, Lesch-Nyhan syndrome, Duchenne (and Becker) muscular dystrophy

42
Q

Duchenne gene and Pathophysiology

A 
Duchenne = deleted dystrophin.
Dystrophin gene (DMD) is the largest protein-coding human gene - inc. chance of spontaneous mutation. Dystrophin helps anchor muscle fibers, primarily in skeletal and cardiac muscle. It connects the intracellular cytoskeleton (actin) to the transmembrane proteins alfa and beta-dystroglycan, which a reconnected to the extracellular matrix (ECM).
Loss of dystrophin - myonecrosis.

inc. CK and aldolase; genetic testing confirms the diagnosis.

43
Q

Myotonic type 1 gene

A

DMPK gene

Defected mytonin protein kinase

44
Q

Myotonic type 1 trinucleotide repeat… + Sx

A

CTG trinucleotide repeat

CTG MAM - Cataracts, Toupee (early balding in men), Gonadal
atrophy, muscle wasting, arrhythmia, myotonia.

45
Q

Rett syndrome mutaion

A

de novo mutation of MECP2 on X chromosome.

“May Experience Cerebral plunge X 2”

46
Q

Fragile X syndrome gene

A

FMR1 (Fragile x Mental Retardation) gene

47
Q

Fragile X syndrome sx

A

FMR1 (Fragile x Mental Retardation) gene

M: Mitral regurgitation, macrognathia, macro-orchidanism, methylation.

48
Q

Myotonic dystrophy MODE Of INHERITANCE

49
Q

Edwards syndrome

A

Prominent occiput, Rocker-bottom feet, Intellectual disability, Nondisjunction, Clenched fists (with overlapping fingers), low-set Ears, micrognathia (small jaw), congenital heart disease, omphalocele. Death usually occurs by age 1.
PRINCE.COM

50
Q

Patau syndrome

A

Findings: severe Intellectual disability, Rocker-bottom
feet, Microphthalmia, Microcephaly,
cleft liP/ Palate, holoProsencephaly,
Polydactyly, cutis aPlasia, congenital heart
(Pump) disease, Polycystic kidney disease,
omPhalocele.
IM MR P7

51
Q

Down syndrome

A 
F- Flat facies
I - intellectual disability
F- fifth finger incurved
T- Toes number 1 &2 have a gap
H- Hirschsprung disease

P- Palmer crease (single)
A - Alzheimer (early-onset -chromosome 21 codes for APP)
C- Cardiac disease (congenital, eg. ASD/VSD)
E - Epicanthal folds (prominent)

A- ALL/AML (increased risk)
B- Brushfield spots
A - Atresia of the duodenum

52
Q

Genetic disorders by chromosome 3

A

von Ilippel-Lindau disease, renal cell carcinoma “VR”

53
Q

Genetic disorders by chromosome 4

A

ADPKD (PKD2), achondroplasia, Huntington disease “AHA”

54
Q

Genetic disorders by chromosome 5

A

Cri-du-chat syndrome, FAD (Polyposis) CraP

55
Q

Genetic disorders by chromosome 6

A

hemochromatosis is (HFE)

56
Q

Genetic disorders by chromosome 7

A

Williams syndrome, cystic fibrosis

57
Q

Genetic disorders by chromosome 9

A

Friedreich ataxia, tuberous sclerosis (TSCI)

58
Q

Genetic disorders by chromosome 11

A

Wilms tumor, Beta-globin gene defects (eg, sickle cell disease, beta-thalassemia), MEN1

59
Q

Genetic disorders by chromosome 13

A

Patau syndrome, Wilson d isease, retinoblastoma (RBI), BRCA2

60
Q

Genetic disorders by chromosome 15

A

Prader-Willi syndrome, Angel man syndrome, Marfan syndrome

61
Q

Genetic disorders by chromosome 16

A

ADPKD (PKDI), a -globin gene defects (eg, a -thalassemia), tuberous sclerosis (TSC2)

62
Q

Genetic disorders by chromosome 17

A

Neurofibromatosis type I, BRCAl, TP53

63
Q

Genetic disorders by chromosome 18

A

Edwards syndrome

64
Q

Genetic disorders by chromosome 21

A

Down syndrome

65
Q

Genetic disorders by chromosome 22

A

Neurofibromatosis type 2, DiGeorge syndrome (22q11)

66
Q

Genetic disorders by chromosome X

A

Fragile X syndrome, X-linked agammaglobulinemia, Klinefelter syndrome (XXY)

67
Q

Robertsonian translocation commonly involves chromosome pairs…

A

13, 14, 15, 21, and 22.

68
Q

Cri-du-chat syndrome

A 
microcephaly, moderate to severe
intellectual disability, high-pitched crying/
meowing, epicanthal folds, cardiac
abnormalities (VSD).
MICE
69
Q

Williams syndrome

A

CARE - high Ca++, Aortic stenosis (supra valvular), Renal stenosis, Elfin face+Elastin gene.

70
Q

Robertsonian translocation occurs when

A

the long arms of 2 acrocentric chromosomes (chromosomes with centromeres near their ends) fuse at the centromere and the 2 short arms are lost.

71
Q

Robertsonian translocation cause

A

Balanced translocations normally do not cause any abnormal phenotype. Unbalanced translocations can result in Miscarriage, Stillbirth, and chromosomal Imbalance (eg, Down syndrome, Patau syndrome).
It causes a MISs!

72
Q

DNA exists in the condensed,_____ form to
fit into the nucleus. DNA loops twice around a
histone octamer to form a ______.

A

chromatin, nucleosome (“ beads on a string”).

73
Q

Two amino acids that have only one 1 codon?

A

methionine (AUG) and tryptophan

(UGG) encoded by only I codon.

74
Q

DNA III and DNA I Exonuclease abilities?

A

DNA III proofreads with 3’ - 5’ exonuclease.

DNA I excises RNA primer with 5’ - 3’ exonuclease.

75
Q
  • Transition-?

* Transversion-?.

A
  • Transition-purine to purine (eg, A to G) or pyrimidine to pyrimidine (eg, C to T).
  • Transversion-purine to pyrimidine (eg, A to T) or pyrimidine to purine (eg, C to G).
76
Q

mRNA start codons

A

AUG (or rarely GUG).

77
Q

microRNAs

A

MicroRNAs (miRNAs) are small, noncoding RNA molecules that posttranscriptionally regulate
gene expression by targeting the 3’ untranslated region of specific mRNAs for degradation or translational repression. Abnormal expression of miRNAs contributes to certain malignancies (eg, by silencing an mRNA from a tumor suppressor gene).

78
Q 
Growth factors (eg, insulin, PDGF, EPO, EGF)
bind tyrosine kinase receptors to...
A

transition the

cell from G1 to S phase.

79
Q

Signal recognition particle (SRP)

A

Abundant, cytosolic ribonucleoprotein that traffics polypeptide-ribosome complex from the cytosol to the RER. Absent or dysfunctional SRP -> accumulation of protein in the cytosol.

80
Q

COPI:

A

Golgi -> golgi

cis-Golgi -> ER.

2 functions - goes back

81
Q

COPII:

A

ER -> cis-Golgi (antegrade).

one function - forword

82
Q

Clathrin:

A

trans-Golgi ->lysosomes;

plasma membrane -> endosomes (receptor-mediated endocytosis [eg, LDL receptor activity)).

83
Q

Microarrays Able to detect

A

single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) for a variety of applications including genotyping, clinical genetic testing, forensic analysis, cancer mutations, and genetic linkage analysis.

84
Q

Karyotyping - Colchicine is added to cultured cells to halt chromosomes in metaphase. Chrnmosomes are stained, ordered, and numbered according to

A

morphology, size, arm-length ratio, and banding pattern

85
Q

Karyotyping - Can be performed on a

A

sample of blood, bone marrow, amniotic fluid, or placental tissue.

86
Q

Hardy-Weinberg law assumptions include: (4)

A
  • No mutation occurring at the locus
  • Natural selection is not occurring
  • Completely random mating
  • No net migration
87
Q

X-linked dominant diseases

A

Hypophosphatemic rickets, fragile X syndrome, Alport syndrome.

XRA!

88
Q

Hypophosphatemic rickets

A

An inherited disorder resulting in inc. phosphate wasting at proximal tubule. Results in a rickets-like presentation.

89
Q

Wernicke -Korsakoff syndrome

Damage to_______, _______

A

medial dorsal nucleus of the thalamus, mammillary bodies.

90
Q

Vitamin B12 deficiency due to…

A

Stomach: Surgery (bypass), Intrinsic factor (dec), aChloridia.
Gut: Crohn disease, Diphyllobatrium latum, Surgery, Sprue and enteritis.
Other: Drugs (metformin), Vegenism, Alchol.

SIC CD’SS Drive Vegans to Alcohol

91
Q

Transmembrane hydrophobic amino acids

A

Trans
T - Tryptophan
L - Leucine
V - Valine

P - Prolin
I - Isoleucine
M - Methionine
P - Phenylalanine

f
A - Alanine
G - Glycine

My step 1 mnemonics (19 decks)

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