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#MedSchool > MCM Final > Flashcards

MCM Final Flashcards

1
Q

This protein sorting pathway is used for proteins destined for cytosol, mitochondria, nucleus, and peroxisomes

A

Cytoplasmic

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2
Q

This protein sorting pathway synthesizes proteins destined for the ER, lysosomes, plasma membranes, and for secretion

A

Secretory pathway

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3
Q

What is the protein sorting signal that, when present, destines proteins for the cytoplasm

A

> Trick question. No sorting signal for this destination.

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4
Q

What is the protein sorting signal that, when present, destines proteins for the mitochondria

A

A hydrophobic alpha helix

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5
Q

What is the protein sorting signal that, when present, destines proteins for the nucleus

A

Terminal Lys/Arg repeats

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6
Q

What is the protein sorting signal that, when present, destines proteins for the lysosome

A

M6P

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7
Q

What is the protein sorting signal that, when present, destines proteins for a secretory vesicle

A

Trp rich domain (absent of retention motifs too)

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8
Q

What is the protein sorting signal that, when present, destines proteins to stay in the ER

A

KDEL

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9
Q

What disease is caused by a defect in the enzyme required to tag proteins with an M6P signal?

A

I cell disease. Proteins (hydrolases to be specific) that should be sent to the lysosome are instead packaged for export from the cell and this causes release of harmful enzymes into the blood. Yikes.

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10
Q

Proteins sent to the mitochondria are recognized by what mitochondrial membrane transporters?

A

TIM and TOM

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11
Q

How are unfolded proteins protected in the mitochondria?

A

Binding to chaperones does the trick (HSP70 specifically)

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12
Q

How do nuclear proteins enter that membrane bound organelle?

A

Via specific nuclear pores

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13
Q

Large proteins destined for the nucleus require a nuclear localization signal which includes four basic residues. Which amino acids are present here?

A

Lys, Arg

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14
Q

Name the segment of a protein synthesized for secreting that binds ER targeting signal and then the ribosome during translation

A

Signal recognition particle

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15
Q

What is used to tether the ribosome/mRNA/peptide complex together (also causes temporary halt in translation)

A

Signal recognition particle (SRP)

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16
Q

Where do proteins undergo post-translational modifications?

A

ER or Golgi

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17
Q

When a protein contains an ER localization signal, that signal binds the SRP which will then bind what on the RER membrane?

A

SRP receptor protein

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18
Q

What confirmation will small proteins spontaneously assume

A

Native conformation

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19
Q

What could happen when large proteins fold without the help of chaperones

A

Aggregation or proteolysis

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20
Q

What is the term for a protein containing a barrel shaped compartment that admits unfolded proteins and catalyzes their folding? Does this require ATP?

A

Chaperonins, yes it is ATP dependent

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21
Q

What is the post translational process that converts inactive forms to active enzymes

A

Proteolytic cleavage

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22
Q

What are the 3 possible post translational protein modifications

A

Glycosylation, phosphorylation, disulfide bond formation

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23
Q

What post translational modification Occurs on extracellular proteins only

A

Glycosylation

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24
Q

What post translational modification can be either O linked or N linked

A

Glycosylation

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25
Q

What amino acids serve as binding sites for an O linked glycosylation of a protein post translationally

A

hydroxyl group of Ser or thr

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26
Q

What amino acids serve as binding sites for an N linked glycosylation of a protein post translationally

A

Amino group of Asn

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27
Q

What type of bond is formed with the addition of a glycosidic post translational modification

A

Ester

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28
Q

Disulfide bonds form between what functional group of cysteine residues?

A

Thiol (-SH)

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29
Q

Formation and reorganization of disulfide bonds occurs where

A

ER lumen

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30
Q

Beta cells of the pancreas produce what 20 residue peptide?

A

Preproinsulin

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31
Q

Preproinsulin has its signal peptide cut off in the ___ to form proinsulin

A

ER

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32
Q

How many intramolecular disulfide bridges form within insulin’s structure

A

2

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33
Q

Insulin moves past the golgi before accumulating in what for storing?

A

B granules

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34
Q

Proinsulin is cleaved twice to release a residue called what?

A

C peptide

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35
Q

Mature insulin is stored in granules as a hexamer bound to what cofactor

A

Zinc

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36
Q

Mature insulin is made of an A and B chained linked together by what?

A

2 disulfide bridges

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37
Q

Most abundant structural protein in vertebrates? (Hint it is heterotrimeric)

A

Collagen

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38
Q

What post translational modification activates procollagen

A

Hydroxylation of lysines at the 5’ end and prolines (and later it can be glycosylated)

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39
Q

What coenzyme is necessary for lysyl and prolyl hydrolases required to activate collagen?

A

Ascorbic acid (vitC)

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40
Q

Each gene occupies a specific place in the genome known as what

A

Locus (plural loci)

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41
Q

The function of what structure is to temporarily hold together 2 daughter DNA helices after replication and serves as attachment site for microtubules during division

A

Centromere

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42
Q

Repeated nucleotide sequences at the two ends of a chromosome essential for stability

A

Telomere

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43
Q

This word. Refers to an. Entire set of chromosomes from a. Single cell

A

Karyotpe

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44
Q

How many pairs of human chromosomes are autosomes

A

22 pairs (and we have 1 pair of sex chromosomes)

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45
Q

Term for 2 Identicle chromosomes join at a centromere

A

Chromatids

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46
Q

This substance is sometimes used to detect the amount of circulating insulin in assays (it can even distinguish between hypoglycemic disorders due to islet cell tumors and infusion of exogenous insulin)

A

C peptide

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47
Q

a mendelian term meaning that two genes are inherited separately from one another: the inheritance of one does not increase or decrease your chances of inheriting the other

A

law of independent assortment

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48
Q

what are the 3 genetic mechanisms of disease and examples of each

A

loss of function: dystrophin, duchenne MD
gain of function: oncogenes causing cancer
protein alteration: sickle cell anemia

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49
Q

what do you call the first person diagnosed in a pedigree? (usually denoted by an arrow)

A

proband

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50
Q

what term do you use to describe that males have only 1 X chromosome? (This is why X linked disorders show up far more frequently in men)

A

hemizygous

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51
Q

whats an example of an X linked dominant disease where phosphorus and calcium in blood is very low due to wacky reabsorption in kidneys

A

hypophosphatemia

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52
Q

the frequency at which a gene manifests itself

A

penetrance

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53
Q

range of phenotypes that vary between individuals with a specific genotype

A

variable expressivity

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54
Q

term describing a single disorder (or any trait) caused by mutation in genes at different chromosomal loci

A

locus heterogeneity

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55
Q

with mutations in collagen genes (could occur in chromosome 7 or 17) we obtain brittle bones and this condition is called what? what process is responsible for the fact that this disease can be caused by mutation at multiple different loci?

A

osteogenesis imperfecta, locus heterogeneity

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56
Q

When binding proteins and enzymes depart from a site of crossing over (during prophases I) the structure that is left where maternal and paternal chromosomes have exchanged parts is called what?

A

Chiasma

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57
Q

Homologs being to pair in prophase I of meiosis and form a 4 chromatid structure called what?

A

A bivalent

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58
Q

What event occurs at the chiasma?

A

Crossing over

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59
Q

Homologs are joined by what protein complex to hold them together during crossing over?

A

Synaptonemal complex

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60
Q

There is a small region of homology between the X and Y chromosome called what? This allows them to pair during meiosis

A

Pseudoautosomal region

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61
Q

What are events that increase genetic diversity in offspring

A

Random assortment, crossing over

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62
Q

A Y chromosome directs the genital ridge to develop into what adult structure

A

Testis

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63
Q

How/Why are all womens technically mosaics?

A

Half of the cells in a woman’s body inactivate the paternal X chromosome and the other half of the cells inactivate the maternal X.

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64
Q

What does it mean when a gene is “imprinted”?

A

Methylated (down regulation)

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65
Q

How many possible gametes can be produced from two parents thanks to random distribution of homologues

A

2^n = 2^23 = 8.4x10^6

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66
Q

When homologues fail to properly separate (common during egg development and increase with maternal age)

A

Nondisjunction

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67
Q

What meiotic deficiency is the leading cause of spontaneous abortion and mental retardation in humans?

A

Nondisjunction

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68
Q

Cells with an abnormal chromosome number are referred to as what? Cell with a normal number of chromosomes are called what?

A

Aneuploid, euploid

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69
Q

When in cell division is nondisjunction most likely to occur for an oocyte?

A

Meiosis I

70
Q

Because male gametes undergo more mitotic cell divisions, they are more susceptible to what?

A

mutations

71
Q

If the paternal chromosome 15 is deleted the child will develop what anomaly?

A

Prader willi syndrome

72
Q

If the maternal chromosome 15 is deleted the child will develop what anomaly?

A

Angelman syndrome

73
Q

What two. Equations are necessary to determine a value using hardy weinberg principle?

A

p2 + 2pq + q2 = 1

p + q = 1

74
Q

What does consanguinity mean? Why is this a bad thing?

A

“Blood relation”

We use this to describe mating with a relative (incest) and it is more likely to produce offspring affected by rare autosomal recessive disorders

75
Q

What is the difference between the terms plolygenic. And multifactorial?

A

Polygenic- trait determined by many genes

Multifactorial- environmental factors cause variation

76
Q

In multifactorial diseases, what threshold must be crossed before the disease will be expressed?

A

Threshold of liability

77
Q

Females have a higher risk threshold and therefore require more risk genes before developing what condition?

A

Pyloric stenosis (hypertrophy between stomach and duodenum)

…side note: because women need more genes before expressing the phenotype, affected women are more likely to pass the trait on to offspring than affected men!

78
Q

Random evolutionary process that produces large changes in gene frequency especially in a small population

A

Genetic drift

79
Q

When a population begins form a small group of individuals who mate within the population, we see a special case of genetic drift known as what?

A

Founder effect (albinism in Panama is an example)

80
Q

The RNA sequence produced from transcription is identicle (except for C’s and U’s) to which strand of DNA

A

Coding strand

81
Q

What is the purpose of a complementary hairpin near the 3’ end of a gene just before the polyU tail

A

It releases the newly synthesized strand from RNApol

82
Q

What are the start and. Stop sequences of the genetic code??

A

Start- AUG

stop- UAA, UAG, UGA

83
Q

Drug that binds 30S subunit of bacterial Ribosome to disrupt translation initiation

A

Streptomycin

84
Q

Drug that binds 60S subunit of Ribosome to disrupt translation elongation

A

Shiga toxin

85
Q

Drugs that binds 50S subunit of bacterial Ribosome to disrupt translocation of the ribosome

A

Clindamycin, erythromycin

86
Q

Drug that binds 30S subunit of bacterial Ribosome to disrupt translation elongation

A

Tetracycline

87
Q

What provides energy for assembly of the initiation complex to begin translation

A

GTP hydrolysis

88
Q

What lab tests are used to diagnose Zika in the first 7 days of infection for individuals with symptoms

A

PCR of urine, serum, or saliva

89
Q

What lab test would you use to diagnose Zika 2-12 days after onset of symptoms

A

Sandwich ELISA with anti-Zika IgM

90
Q

These signaling molecules bind a promoter with a specific DNA binding domain plus a transactivating domain (binds RNA pol II) activating or inhibiting a gene

A

transcription factor

91
Q

transcription factors can independently regulate the same gene in different tissues by binding to separate ___ for that gene?

A

enhancers

92
Q

the capacity to respond to an inductive signal (such as a transcription factor signal during development)

A

competence

93
Q

growth and differentiating factors are part of what family of signaling molecules essential to development? They are proteins (ligands) secreted by a cell and diffuse a short distance to interact with other cells.

A

paracrine signalling

94
Q

60 amino acid helix turn helix DNA binding domain that is used to classify transcription factor family

A

homeodomain

95
Q

the DNA sequence used to encode a homeodomain is a “homeobox” and homeobox containing genes are known as what?

A

HOX genes

96
Q

genes that are related by duplication within a genome are called what? they evolve in function over time.

A

paralogous

97
Q

this gene family plays an important role in caudo-cranial segmentation of the developing body

A

HOX genes

98
Q

HOX genes are activated and expressed from 3’ to 5’. genes found at which end of the coding region are expressed earlier and more ANTERIORLY in the developing organism

A

3’

99
Q

HOX genes are activated and expressed from 3’ to 5’. genes found at which end of the coding region are expressed later and more POSTERIORLY in the developing organism

A

5’

100
Q

Which set of genes is complexly regulated and primarily is concerned with setting up segmental structures along the main body axis

A

HOX

101
Q

what is the major regulator of HOX genes?

A

retinoid acid (vitA)

102
Q

1) when HOX genes are mutated and upregulated (gain of function), what kind of malformation ensues?
2) when HOX genes are mutated and down regulated (loss of function), what kind of malformation ensues?

A

1) anterior to posterior transformation

2) posterior to anterior transformation

103
Q

each gene in this gene family contains a 128 AA paired domain which binds DNA and plays critical role in formation of tissues and organs during embryo development

A

Pax genes

104
Q

this pax gene disorder is characterized by complete or partial absence of the iris (PAX6 mutation)

A

aniridia

105
Q

this pax gene is involved in making proteins that develop the eyes, CNS, and pancreas. when mutated, aniridia ensues

A

Pax6

106
Q

this large family of homeodomain proteins bind both in the nucleus and cytoplasm. They are involved in formation of body segments and without them headless mammalian embryos result

A

Lim proteins

107
Q

this phylogenetically conserved family of genes plays a role in patterning outgrowth of appendages in early embryogenesis and formation of jaws and inner ear

A

Dlx genes

108
Q

this family of genes prenatally inhibits cell differentiation and postnatally helps to maintain proliferative capacity of tissues (involved in epithelial-mesenchymal interactions in the face and limbs)

A

Msx genes

109
Q

this gene family causes short tails in heterozygous mice, is important ion mesodermal germ layer development, and differentiates forelimb from hindlimb

A

Tbx genes

110
Q

this family of transcription factors have 2 alpha helices separated by a short amino acid loop with adjacent basic regions

A

helix loop helix TF’s

111
Q

this configuration is common in TF’s that regulate myogenesis

A

helix loop helix & zinc finger proteins

112
Q

helix loop helix and zinc finger transcription factors are common in regulating what part of development

A

myogenesis

113
Q

TF family that regulates expression of genes involved in cell growth, proliferation, differentiation, longevity (and they contain a winged helix)

A

Fox gene family

114
Q

the first gene associated with disorders of speech and language development (which are highly heritable)

A

FoxP2

115
Q

this configuration of transcription factors include cys and his units bound by a cofactor which causes puckering in the polypeptide chain which can be inserted into specific regions of DNA helix

A

zinc finger proteins

116
Q

this configuration of transcription factor is implicated in bone, cartilage, and tooth development

A

zinc finger

117
Q

a deficiency in this metal ion can result in skeletal growth retardation (risk for osteoporosis)

A

zinc

118
Q

this gene family binds the minor groove in DNA using zinc finger proteins. they are part of HMG-box superfamily and mutations lead to abnormal development of tissues such as sex determining genes

A

Sox (SoxA=SRY sex determining region of Y)

119
Q

this disorder is caused by sox9 mutations effecting skeletal, reproductive, respiratory, and face development resulting in short legs, dislocated hips, ambiguous genet alit, softened respiratory cartilage, ect

A

campomelic dysplasia

120
Q

campomelic dysplasia is caused by mutations in which gene

A

sox9

121
Q

this zinc finger protein affects an isolated gene with important role in kidney and gonadal development

A

WT1 (wilms’ tumor supressor gene)

122
Q

what are the zinc finger TF’s that we need to know?

A 
WT1 (wilms tumor- kidney)
and sox (bone, repro, respiratory issues)
123
Q

this superfamily of signaling molecules plays a variety of roles in embryogeneiss and postnatal life (formation, structure, modification)

A

TGF-beta (transforming growth factor)

124
Q

noggin, chordin, WNT3a, and FGF all “inhibit the inhibitor” of neural development. what is this inhibitor which they block so that neural development can occur?

A

BMP4 (important in skeletal development)

125
Q

if bmp4 is present, then ectoderm becomes ___ whereas if it is blocked, then ectoderm becomes ____

A

epidermis, neural plate

126
Q

angiogenesis, wound healing, embryo development of limb and brain, and various endocrine signaling pathways are all influenced by this family of proteins

A

fibroblast growth factors

127
Q

this protein family uses ligand signaling by binding to PTCH receptors which signal transmembrane SMO protein

A

hedgehog

128
Q

what are the 3 hedgehog proteins?

A

sonic, desert, indian

129
Q

vertebrate organogenesis, facial and limb patterning, brain organization is all influenced by what signaling factor

A

SHH

130
Q

this growth factor is essential in stem cell division in adults and has been implicated in cancer development

A

SHH

131
Q

this signaling factor is involved in chondrocyte differentiation, proliferation, maturation especially during endochondral ossification

A

IHH (indian hedgehog)

132
Q

defects in this signaling factor causes partial gonadal dysgenesis (PGD) and polyneuropathy

A

DHH (desert hedgehog)

133
Q

this signaling factor is important in gastrulation and organogenesis and binds frizzled and LRP receptors, uses a signal transducer to beta catenin which enters nucleus to activate target genes

A

wnt

134
Q

these genes regulate cell growth and differentiation and can lead to cancer when activated (usually code for mitogenic signals)

A

proto-oncogenes

135
Q

these genes normally function to limit frequency of cell division and when they lose function, cancer may develop

A

tumor supressor genes

136
Q

which tumor suppressor gene, when it loses function, leads to basal cell carcinoma

A

PTCH

137
Q

RAS, HER2, EFT receptor, MYC, and ABL are all examples of what kind of cancer causing gene

A

proto-oncogene

138
Q

p53, RB, APC, DCC, BRCA, and NF-1 are all examples of what kind of cancer causing gene

A

tumor supressor

139
Q

activation of p53 leads to p21 activation which is a protein that binds cyclin-CDK complexes for G1/S transition. This process keeps ___ hypophosphorylated and active, and consequently sequesters ___

A

Rb, E2F

140
Q

during early development, this signal molecule is generated in a region of the embryo to determine anterior/ posterior axis development by acting through box genes. what is the signaling molecule?

A

retinoid acid (vitA)

141
Q

cultured embryonic stem cells can be coaxed into becoming neurons if you add what signaling molecule?

A

retinoic acid

142
Q

the heavy and light chains of an antibody together form what portion of the structure

A

Fab portion

143
Q

the Fc portion of an antibody contains components of which chains?

A

heavy chains only

144
Q

the portion of an antigen to which an antibody attaches

A

epitope

145
Q

in a method known as indirect detection, two ___ are used (the second one is fluorescently labeled) to amplify a detectable signal

A

antibodies

146
Q

enzyme amplification assay frequently used in medicine the amount of antibody present in solution as it binds an antigen coated well (test for HIV Ab’s)

A

indirect ELISA

147
Q

enzyme amplification assay where production of color indicates the quantity of antigen between one bound and one unbound monoclonal antibody which emit color when substrate is added (test for hCG: pregnancy)

A

sandwich ELISA

148
Q

what lab method is used to detect cardiac troponin T before and after an MI

A

ELISA

149
Q

what lab method uses DNA transcription as a diagnostic tool to find short tandem repeats (STRs) or viral particles

A

PCR

150
Q

what are examples of conditions diagnosed using PCR?

A

chlamydia, CMV, Hep C, tuberculosis, gonorrhea
MSUD, ornithine transcarbamoylase deficiency, PKU, CF, Duchenne MD, Rb, familial hypercholesterolemia, sickle cell anemia, G6P dehydrogenase deficiency, tay sachs, hemophelia, lesh nyhan syndrome

…so when in doubt, its probably diagnosed using PCR :)

151
Q

what are examples of conditions diagnosed using qPCR?

A

strep, HIV

152
Q

name the technique where reverse transcriptase is used to make DNA from RNA sample and we add fluoresent marker linked to a probe to find a complementary sequence. a scanner measures expression. What are examples for use of this method?

A

microarray

chemo-resistant tumors

153
Q

which viruses are known to be oncogenic

A

EBV, Hep B, HPV, HTLV-1, KSHV (kaposi sarcoma herpes virus)

154
Q

Zika has an advantage in humans because of what disguise?

A

It acquires an envelope from our cells

155
Q

What is the most devastating time to acquire zika in a pregnant woman? Why?

A

First trimester

Organogenesis (infects neural cells)

156
Q

What property of signalling molecule allows it to diffuse across the cytoplasmic membrane and bind intracellular receptors?

A

Small hydrophobic (steroid hormones for example)

157
Q

Most signalling molecules require cell surface receptors because they have what property?

A

Hydrophillic (such as growth factors)

158
Q

Retinoic acid is a vitamin A derivative that acts through which set of developmental genes? These genes control positioning along which body axis?

A

Hox genes, these control anterior/posterior patterning

159
Q

what method of cell signaling elicits a fast response

A

change in function of enzymes

160
Q

what method of cell signaling elicits a slow response

A

change in expression of genes

161
Q

Long distance signaling in the bloodstream of freely diffusible signals

A

Endocrine

162
Q

Signaling acting locally on cells nearby using short lived signals such as neurotransmitters

A

Paracrine

163
Q

Cells respond to signals released by themselves such as growth factor

A

Autocrine

164
Q

Signalling involving direct contact with receptor such as with antigen presentation in immune cells

A

Juxtacrine

165
Q

the same ligand can elicit different responses when introduced to different tissues for example: acetylcholine causes heart muscle cells to do what? skeletal muscle? salivary gland?

A

relax, contract, salivate

166
Q

where would you find a receptor for a small hydrophobic ligand? what about a receptor for hydrophilic molecules?

A

intracellular, cell surface

167
Q

what are the hydrophobic ligands?

A

cortisol, estradiol, thyroxine, testosterone, vitD3, retinoic acid

168
Q

what kind of receptor is most commonly the target of drugs

A

GPCR

169
Q

g proteins are regulated in part by two enzymes that help facilitate the production and hydrolysis of GTP. Which enzyme activates a GPCR and which inhibits?

A

activates- GEF- exchanges GTP for GDP and keeps GPCR in active state (GTP bound)
inhibit- GAP- hydrolyzes the GTP bound to GPCR so that it “turns off” (GDP bound)

170
Q

which subunit of a gpcr is catalytically acitve

A

alpha

#MedSchool (17 decks)

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