Foundations 1 Test MIsc Week 1-2 Flashcards Preview

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Flashcards in Foundations 1 Test MIsc Week 1-2 Deck (105)
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1
Q

Allelic heterogeneity

A

one disease caused by different mutations in the same gene

2
Q

Locus Heterogeneity

A

one disease caused by different mutations in different (but related) genes

3
Q

Clinical Heterogeneity

A

disease with different phenotypes that are caused by mutations in the same gene (when you have Type I, Type II… of disease)

4
Q

what are the two largest contributors to genetic diversity between individuals?

A

SNPs (most common) and Copy number variants (second most common).

5
Q

Role of CNVs? what are they?

A

variation in number of copies in one or more sections of DNA. important in development of special senses

6
Q

Tandem repeats: types? role (general)?

A

Satellites, minisatellites, microsatellites. Generally found in non-coding regions of DNA and play a structural or protein binding role. Ex: telomeres (minisatellites) prevent chromosome shortening, alpha-satellites form binding site for kinetichore in all chromosomes

7
Q

non-sense mutation

A

premature stop codon

8
Q

missense mutation

A

code for new AA

9
Q

silent mutation

A

code for same AA

10
Q

proteins synthesized by free ribosomes are destined for (4)?

A

nucleus, mitochondria, peroxisome, cytosol

11
Q

what is the role of signal peptides?

A

direct proteins where to go. Nucleus, mitochondria, ER

12
Q

what the difference between free ribosomes and ER bound ribosomes

A

nothing other than their location. ER ribosomes are directed to the ER only after they translate a protein containing an ER localization protein

13
Q

Contrasted to the signal peptides that locate a protein to the nucleus or mito, where does the signal peptide that localizes a protein to the ER end up?

A

in the ER membrane (where it is eventually degraded)

14
Q

In what gene is the sickle cell mutation? What is the mutation

A

Beta globin. Glu6Val mutation

15
Q

Compare the lifespan of a normal RBC to that of a sickle cell

A

Normal=120 days

Sickle=10-20 days

16
Q

What is the role of MUTYH? What condition results from Biallelic LOF?

A

MUTYH is responsible for BER of 8-oxo guanine nucleotides. Without, MAP occurs (colon polyps)

17
Q

What is the rationale behind using PARP1 inhibitors to treat breast cancer in individuals with BRCA1/2 mutations.

A

PARP1 is responsible for the repair of ssDNA. BRCA1/2 mutants have lost the ability to repair dsDNA. Eliminating these cells only remaining metho to repair DNA breaks (PARP1 inhibitors) will cause cell death.

18
Q

What proteins should you associate with the repair of dsDNA breaks?

A

BLM, ATM, FANC, BRCA1/2, NBN

19
Q

What is the diagnostic test for sickle cell anemia

A

Electrophoresis Hbs does not move as far on the gel

20
Q

What is trisomy 18? Symptoms?

A

XY, 47, +18. Posteriorly rotated ears, small features with large head, unusual fingers (2nd and 5th digit overlap)

21
Q

What is Patau syndrome??? Features?

A

Trisomy 13. Midline abnormalities (cleft lip, heart defects, brain and SC abnormalities)

22
Q

What is a robertsonian translocation?

A

A translocation involving two Acrocentric chromosomes. Results in individuals that have a full amount of DNA but are lacking a chromosom, this is problematic for reproduction (if it is in the germ-line)

23
Q

What occurs during pre-mRNA processing?

A

Introns are removed, 3’ poly A tail is added, 5’ cap is added

24
Q

What is the inheritance of sickle cell?

A

Auto recessive

25
Q

What is the general difference between thalassemia and sickle cell.

A

Sickle: abnormally shaped RBCs that are Lysed due to their shape
Thalassemia: a decreased amount of Hb subunits (alpha or beta) created causing a decreased (decreased number of hypochromic RBCs) amount of RBCs

26
Q

What would be expect to see an increase in blood of in individuals with sickle cell?

A

Increased reticulocytes, increased products of hemolysis (Fe, bilirubin)

27
Q

DMD vs. BMD

A

DMD is a more severe form of BMD in which Dystrophin is absent. Dystrophin is truncated in DMD. This causes muscle weakness in skeletal and cardiac muscle

28
Q

DMD inheritance

A

X-linked recessive (most common X-linked disorder in men)

29
Q

what is SMA? Cause?

A

spinal muscle atrophy caused by a loss of SMN protein (motor neuron degenerative disease that leads to muscle atrophy)

30
Q

what are the type of Osteogenesis imperfecta?

A

Type I: null allele, loss of one of the alleles for alpha-1 chains of procollagen; less procollagen is made

Type II: generally fatal, incorporation of mutant alpha-1 chains into pro-collagen causing a dominant negative effect where only 1/4 of procollagen is functional

31
Q

what is the “huntington’s chromosome”

A

the polyglutamine expansion seen in huntingtons disease where 36-121 CAG repeats are exist. this is over the threshold for repeats and this person will have huntingtons (10-30 repeats=no HD)

32
Q

what is achondroplasia? what causes it?

A

dwarfism caused by a mutation (G380R) that leaves FGFR3 always active and thus always inhibits bone growth

33
Q

what is swyer syndrome? cause?

A

males develop female sex characteristics due to the inability of SRY TF to localize to the nucleus (loss of nuclear import sequence

34
Q

what are the fates of proteins translated at the rER?

A

rER, PM, Golgi, endosome, lysosome, exocytosed

35
Q

what are the fates or proteins translated in the cytosol?

A

Cytosol (if no signal sequence), nucleus, mitochondria, peroxisome

36
Q

how do 8-oxoguanine nucleotides form?

A

ROS, these nucleotides are as likely to binds with A as C

37
Q

Cytoxan and platinum compounds are used as what? why?

A

cancer therapies b/c they stop DNA replication

38
Q

Contrast HbS, HbC, HbF, HbE, HbA

A
HbS: sickle cell Hb (Glu6Val)
HbC: abnormal Hb caused by Glu6Lys mutation; form HbC crystals
HbF: fetal Hb
HbE: a non-detrimental variant of Hb
HbA: normal adult Hb
39
Q

what is Heinz Body Hemolytic Anemia?

A

unstable Hb that degrades and coagulates in RBCs to form Heinze bodies. RBC hemolyze

40
Q

What are the two main causes of hemolytic anemia? what is the MOA?

A

G6PD Deficiency: decreased NADPH and glutathione results and increased damaging ROS (bite cells)

PK deficiency: decreased ATP produced (Acanthocytes)

41
Q

what are three ways in which protein folding is “helped” (prevents aggregates)

A

PDI, PPI, Chaperones

42
Q

what are 4 diseases of protein folding?

A

localized amyloids (azheimers), prion disease, alpha-1-antitrypsin deficiency, systemic amyloidosis

43
Q

how do high MW chaperones function?

A

form anfinsen cage around proteins that seqeuster them from the crowded folding environment

44
Q

Specificity:

A

TN/TN+FP

45
Q

Sensitivity:

A

TP/TP+FN

46
Q

when do you optimize sensitivity

A

when you want to decrease the number of false negative; diseases that are easily spread

47
Q

when do you want to optimize specificity?

A

when you want to decrease the number of false positives; for diseases that are deadly

48
Q

what causes systemic lupus erythematosus? symptoms?

A

autoimmune disorder that attacks SnRNPs (used in RNA splicing). joint pain, swelling, butterfly rash on face

49
Q

what causes testicular feminization

A

46, XY individuals that lack androgen receptors (TFs, b/c androgen diffuse through PM)

50
Q

what are the 4 types of protein-membrane assoications? which are integral? peripheral? which can be removed by a change in pH or ionic composition? which must be removed by detergent?

A

Integral: transmembrane, membrane associated, lipid linked; removed with detergant

peripheral: protein attached; removed by change in pH or ionic composition

51
Q

Cell cortex vs. glycocalyx

A

Cell cortex: meshwork of proteins inside the cell; stabilizes PM

Glycocalyx: layer of sugar on outer membrane that serves to lubricate cells, cell-cell recognition and protects from mechanical damage

52
Q

what is the role of clatherin and adaptin?

A

Buzz word: vesicle budding!

Clatherin forms a protein coat around budding vesicles through its attachment to adaptin (adaptin attaches to cargo receptor which is a transmembrane protein that attaches to intracellular cargo); clatherin and adaptin help the vesicle pinch off (dynamin) and sorts cargo within the vesicle

53
Q

what is the fate of clathrin and adaptin?

A

shed off vesicle prior to it binding to its target

54
Q

other than exocytosis, when is clatherin used?

A

receptor mediated endocytosis

55
Q

what is the role/location of Rab, tethering protein, v-snare, t-snare

A

Buzz word: vesicle binding to target

Rab: on vesicle
Tethering protein: on target membrane, binds Rab
V-snare (on vesicle)/t-snare (on target membrane): bring the vesicle close to the PM for fusion

56
Q

what is the pathway of protein secretion starting as mRNA and ending as an extracellular protein?

A

mRNA–>rER–>Golgi–>PM–>outside cell

57
Q

what are three modifications made to proteins in the ER?

A

glycosylation (dolichol), disulfide bond formation (DPI), lipid membrane anchors

58
Q

release of GLUT4 is what type of endocytosis?

A

receptor mediated endocytosis that is triggered by insulin binding to liver or muscle cells

59
Q

what is the role of M-6-P? where is it added?

A

M-6-P targets rER made acid hydrolases to endosomes. it is added to the acid hydrolases in the GOLGI

60
Q

what type of endocytosis is the uptake of LDL cholesterol?

A

receptor-mediated endocytosis; clatherin dependent, allows for concentration within the cell

61
Q

once in the cell, what is the fate of LDL?

A

LDL is just a carrier of cholesterol and thus must be degraded if cholesterol is to be used. LDL fuses with an endosome and is delivered to a lysosome where it is degraded and cholesterol freely passes out of the lysosome

62
Q

what is familial hypercholesterolemia?

A

a lack of LDL receptors which leads to the accumulation of cholesterol within the blood (cant be taken up by cell), result in “fuzzy macrophages” (xanthoma, atherosclerosis)

63
Q

what is Fick’s law?

A

relates to simple diffusion; Net flux=(K x Area x Concentration gradient)/distance

K: increases with hydrophobicity and decreases with size

64
Q

what are the main 3 symporters? in what direction do they move substance?

A

Na/Cl/Na, Na/Glucose and Na/AA move both into the cell (secondary active transport)

65
Q

what are the two main anti-porters? in what direction do they move substance?

A

Na/H and Na/Ca antiporters. move Na into the cell. Ca and Na are moved out of the cell

66
Q

the movement through GLUT is what type of transport

A

facilitated diffusion

67
Q

which ion is responsible for maintaining the resting membrane potential? why?

A

K. many K channels are open, few Na channels are open. the nernst equilibrium potential of K is -98 mV and the resting membrane potential is -70 mV suggesting that at the resting membrane potential K+ continuously moves out of the cell.

68
Q

what is the nernst eqn? what does it tell us?

A

60/Z x Log([C,out]/[C,in])

give the membrane potential in which a particular ion will not move in or out of the cell based on its concentration gradient and electrical gradient.

69
Q

do RBCs contain aquaporins?

A

yes! 200,000 per molecule. explains why they are so sensitive to changes in tonicity

70
Q

Adrenergic receptors are what type of receptor? what binds them?

A

GPCR bound by E/NE

71
Q

what does the stimulation of adrenergic receptors oft he heart do?

A

mostly BETA adrenergic receptors here. Increases HR and contractility

72
Q

what are beta blockers used for 2? how?

A

Beta receptor ANTAGONISTS

  1. Treat high BP; decrease HR
  2. Treat heart failure: counters the effects of B-AR desensitization due to chronically high catecholamine levels
73
Q

Gs and Gi general pathway

A

Gs: activates adenyl cyclase, increases cAMP, activates PKA that can phosphorylate proteins in cytosol (CFTR, muscle contractions in heart) or activate gene transcription in nucleus.

Gi: inhibits adenyl cyclase

74
Q

describe GPCR desensitization (specifically B-AR)

A

chronically high levels of NE/E (such as those released during heart failure) can desensitize B-AR receptors.

75
Q

role of GRKs

A

Phosphorylate and inactivate GPCR activity

76
Q

how does cholera toxin work?

A

the G-alpha subunit of the Gs pathway is always active leading to high levels of cAMP and severe dehydration

77
Q

describe the G-beta subunit signaling

A

Buzzwords: PKC and Calcium

G-beta activates PLC which cleaves PIP2 into IP3 and DAG. IP3 opens Ca channels in ER and DAG activates PKC. Calcium signaling and phosphorylation occurs

78
Q

RTK buzzwords

A

Dimerization, auto-phosphorylation, SH2, GROWTH FACTORS, Ras, Insulin, AKT, MAP-Kinase cascade, PI-3K

79
Q

what is the signaling pathway for insulin binding to insulin receptor

A

RTK!!!! PI-3K signaling pathway causes exocytosis (receptor-mediated exocytosis) of GLUT4 containing vesicles

80
Q

describe NO signaling

A

Ach binds receptor and activates NO synthase (Argininge–>NO). NO can then diffuse into cells and activate guanyl cyclase. this creates cGMP and causes smooth muscle relaxation within blood vessels

81
Q

JAK-STAT pathway: receptor type? effects?

A

CYTOKINE (inflammation and immunity) receptor. recruit JAKs (b/c dont have own intrinsic kinase activity) that activate STATs. STATs are TFs.

82
Q

TGF-beta receptors

A

bind TGF-Beta ligands, phosphorylate and activate SMAD proteins that act as TFs, Ser/Thr Kinases

83
Q

CFTR is a ____ gated and ____activated ion channel

A

ATP gated

PKA-cAMP activated

84
Q

what is the number one cause of morbidity and mortality in CF?

A

blocked exocrine glands of the lungs due to thick mucous excretions. this causes scaring and end stage lung disease

85
Q

what % CFTR function is needed to avoid symptoms?

A

10% only, only need to improve CFTR fxn to 10% to treat CF

86
Q

Correlations in CF: which issues (pancreatic insufficiency, sweat chloride, respiratory issues) have the strongest correlation with mutation class

A

pancreatic: strong correlation with Class I-III mutations

Sweat chloride: moderate

lung fxn: weak

87
Q

relate the presence of absence of vas deferens, positive sweat test, pulmonary infection, and PI with level of CFTR fxn (% of normal)

A

10>x>5: absence of vas deferens (AOVD)

5>x>4.5: AOVD, positive sweat test

4.5>x>1: AOVD, positive sweat chloride, respiratory issues

88
Q

sweat chloride for CF:

A

60 mmol/L is CF

89
Q

what is the relavence of the poly T and TG tracts in CF?

A

Alter pre-mRNA splicing of exon 9. 7T and 9T=normal, 5T=detrimental. TG13 and TG12 are detrimental, TG11 is normal. these variants increase risk for CF but do not cause it, more severe when cis-acting.

90
Q

what percent of newborns screen positive for CF?

A

90%

91
Q

buzzwords for autophagy

A

cell stress induced, degradation of organelles

92
Q

what sort of things end up being targeted to a endosome (and eventually a lysosome) 3

A
  1. endocytosed materials (LDL)
  2. newly produced ER proteins (Acid hydrolases)
  3. cytsolic proteins (damaged organelles, autophagy)
93
Q

buzzwords for Macroautophagy, microautophagy and chaperone-mediated autophagy

A

Macro: isolation membrane/autophagosome, organelles, protein aggregates

micro: autophagic tube (in the lysosome itself)
chaperone: selective, degrades long-lived proteins, LAMP2A (in lysosomal membrane translocates protein into lysosome), cytosolic Hsc70

94
Q

role of mTOR

A

in nomral cells mTOR inhibits expression of autophagy genes. under cell stress, autophagy genes are up-regulated

95
Q

statin MOA

A

inhibit HMGCoA reductase and lowers cholesterol (decreases production of cholesterol in the liver)

96
Q

digitalis MOA

A

inhibits Na/K ATPase

97
Q

Cholchicine MOA

A

binds tubuline to prevent MT polymerization

98
Q

agonist

A

activates receptor; has affinity and intrinsic activity

99
Q

antagonist

A

binds and prevents receptor from activating (beta blockers); affinity with no intrinsic activity

100
Q

a drug is non-selective if…

A

if a drug interacts with one receptor but that receptor regulates multiple processes

if a drug interacts with multiple receptors

101
Q

Therapeutic Index

A

TD50/ED50….larger value=better

102
Q

Margin of Safety

A

MS=LD1/ED99

103
Q

non-selective beta blockers 2

A

propanolol, sotolol

104
Q

selective beta blockers

A

metoprolol, esmolol, atenolol

105
Q

Myasthenia Gravis: Cause? Symptoms? Treatment?

A

Body produces antibodies against ACh. Muscle weakness (NO signaling). ACh-esterase inhibitors can be used to increase ACh

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