Exam 3 pt 2 Flashcards

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1
Q

insulin is made with bacteria process

A
  • The two different polypeptides (A chain and B chain) are inserted into different plasmids and then put into bacteria (transformed).
  • The cells are cultured. Purified B-galactosidase-insulin fusion proteins.
  • Treat with CNBr. CNBr cleaves the peptide bond after methionine.
  • purify A and B chains.
  • Refolding and disulfide bond formation
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2
Q

the cycle threshold is reached when

A

the accumulation of fluorsecense is much greater than the background fluorescence detected by a thermocycler

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3
Q

Why do many researchers include GADPH in their Northern Blot experiment?

A

Because GAPDH is expressed at the same level in all cell types, researchers include it in their Northern blot experiments as a control. It confirms that the same amount of RNA is present for each cell type and that the Northern blot was successful.

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4
Q

Why are The A and B chains are linked to 𝛽-galactosidase in production of insulin

A

This is done so that the fusion protein is stabalized. If the chains were not linked to 𝛽-galactosidase, then they would be degraded, and 𝛽-galactosidase increases stability.

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5
Q

why are The purified proteins are treated with cyanogen bromide in insulin making

A

This is done to cleave off the beta-galactosidase portion of the protein. This cleaves the peptide bond connecting the fusion proteins to separate them into separate proteins. This allows the protein to form into insulin and fold properly.

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6
Q

biological control

A

the use of living organisms or their products to alleviate plant diseases or damage from environmental conditions.
* Ex: Bt is natural occurring and kills caterpillars and insects but is nonharmful to humans and plants. Put on crops

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7
Q

bioremidation

A

the use of microorganisms to reduce enviromental pollutants
Ex: microorganisms to treat and degrade sewage

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8
Q

biotransformation

A

enzymes produced by the microorganism transform the structure of the toxic pollutant

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9
Q

how is a gene knockin made in mice

A
  1. gene of interest is cloned and flacked with peices of DNA that are homologous to a noncritical site in the mouse genome
  2. cloned DNA introduced into a mouse oocyte
  3. gene of interst inserts into the noncritcal site by homologous recombination
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10
Q

gene reduncy might mean

A

that a gene knockout has no effect

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11
Q

procedure of making a protein be screted in milk

A
  1. insert gene in plasmid next to milk specific promoter
  2. DNA injected into sheep oocyte
  3. female transgenic offspring secrete protein in milk
  4. purify protein from milk
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12
Q

cloning of animal how

A
  1. donor sheep’s mammary cell is extracted and grown in flask
  2. another sheeps unfertilized egg is extracted and nucleus removed
  3. mammary cell and egg with no nucleus are fused with electrical pulses
  4. egg starts turning into an embryo with donor DNA and egg proteins
  5. embryo put in surrogate
  6. identical sheep born
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13
Q

dolly age problems

A

seemed to be as old as donor bc shorteing of telomeres matched the donor

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14
Q

stem cells characteristics

A
  • capacity to divide
  • differentiate into anything
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15
Q

totipotent cells

A

can give rise to all cell types

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16
Q

pluripotentent

A

can turn into most cell types

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17
Q

multipotent

A

several cell types can turn into

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18
Q

unipotent

A

can only turn into one cell type

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19
Q

hematopoietic stem cells are

A

multipotent

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20
Q

most ES cells from

A

IVF

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21
Q

most EG from

A

aborted fetuses

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22
Q

induced pluripotent stem cells

A

made pluripotent, but how to make them differentiate?

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23
Q

DNA microarray is

A

plastic slide with many sequences of DNA

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24
Q

microarray can

A

identify genes that are transcribed

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25
Q

DNA fragments on a microarray can be

A
  • amplified by PCR and then spotten onto the microarray
  • synthesized directly on the microarray itself
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26
Q

how is microarray used to study gene expression

A
  • islate mRNA
  • make cDNA that is fluorescently labeled
  • hybridize cDNA to microarray
  • view on a lser scanner
    *
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27
Q

microarrays make it possible

A

to study the expression of the whole genome under different enviromental conditions

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28
Q

goal of ChIP

A

to determine where target protein binds in genome

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29
Q

ChIP steps

A
  1. add formaldehyde to crosslink proteins to DNA
  2. lyse the cells
  3. sonicate DNA into small peices
  4. add antibodies that recognize the protein of interest
  5. the antibodies are bound to heacy beads
  6. centrifuge the sample
  7. pellet contains protein of interest, linked DNA
  8. uncrosslink the pellet
    two options:
    * if have an idea of DNA: conduct PCR of DNA
    * if PCR amplifies then the protein of interest was bound to the DNA region that is flanked by the primers

OR

  • attach linkers
  • conduct PCR with linkers and flurescence
  • do microarray
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30
Q

RNA seq used to

A

study the simultaneous transcription of many genes

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31
Q

transcriptosomes

A

the set of all RNA molecules that are transcribed in one cell or a population of cells

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32
Q

RNA Seq technique

A
  1. isolate RNA
  2. break RNA into small samples
  3. add linkers to the RNA
  4. synthesize cDNA with reverse transcriptase PCR
  5. sequence cDNA
  6. align the cDNA sequences along the genomic sequence
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33
Q

RNA seq advantages over microarrays

A
  • more accurate at quanitfying the amoung of each RNA
  • superior at detecting RNA in low abundance
  • shows exact boundries between exons and introns
  • identifies 5’ and 3’ end of RNA transcripts
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34
Q

gene knockout collections allow

A

researchers to study gene function at the genomic level

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35
Q

recognition strategies

A
  • sequence recognition
  • pattern recognition
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36
Q

recognition strategies

A
  • sequence recognition
  • pattern recognition
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37
Q

search by signal

A

tries to locate an organization of known sequence elements that are normally found within a gene

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38
Q

search by content

A

tries to identify sequences that differ significantly from a random idstribution due to codon bias

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39
Q

open reading frame searching

A

looking for a region that does not contain any stop codons

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40
Q

homolous genes

A

are derived from the same ancestral gene

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41
Q

7 observations that show that a disease could be genetic

A
  1. disorder more likely to occur in genetic relative than general population
  2. identical twins share disease more than fraternal
  3. does not spread to individuals sharing an enviroment
  4. different populations tend to have different frequencies of the gene
  5. disease has an age of onset
  6. resembles a genetic disorder seen in other mammals
  7. correlation is observed between disease and a gene or chromosome alteration
42
Q

personalized medicine

A

use of patients genotype and other things to treatment

43
Q

concordance

A

degree to which a disease is inherited

44
Q

concordance calculation

A

perceptage of twin pairs in which both the twins exhibit the disorder

identical twins = concordance is one

45
Q

features of autosomal recessive inheritance

A
  • an affected offspring have two unaffected parents
  • when two unaffected hetrezyotes have children, ~25% have disease
  • two affected peoples children have 100%
  • occurs with the same frequency in both sexes
46
Q

disorders that involve _ are typically autosomal recessive

A

loss of function in enzymes

50% of functional enzyme enough for healthy heterozygote

46
Q

disorders that involve _ are typically autosomal recessive

A

loss of function in enzymes

50% of functional enzyme enough for healthy heterozygote

47
Q

autosomal dominant inheritence features

A
  • always have affected parent
  • one affected parent have 50% affected offspring
  • two affected hetrozygotes have 75% offspring affected
  • same frequency in both sexes
  • homozygouse more severly affected
48
Q

three explanations for dominant disorders

A
  • haploinsufficiency (50% not enough for non affected phenotype)
  • gain of function mutation
  • dominant negative mutation (mutant acts acts the wild type)
49
Q

features of x linked recessive

A
  • males more likely to show the trait
  • mothers of affected males have brother or fathers who are affected
  • the daughters of affected males will have 50% affected sons
50
Q

x linked dominant inheritance features

A
  • males more severly effected
  • females show trait when it is lethal to males
  • affected mothers have 50% passing the trait to daughters
51
Q

locus heterogeneity

A

a disease can be caused by mutations in two or more different genes

52
Q

microarrays in cancer

A
  • can characterize tumors
  • show the difference in cancers
  • shows expression, cancer patients have more expression in certain type of cells that can show different types of cell cancer that presents the same
53
Q

pharmacogenetics

A

the study or clinical testing of genetic variation that cuases different responses to drugs

54
Q

characteristic of cancer

A
  • clonal
  • multistep process
  • invasic and matastatic
55
Q

clonal

A

cancer cells originate in a single cell

56
Q

two types of cancer genes

A

oncogene
tumer supressor gene

57
Q

oncogenes are _ mutations while tumor supressor genes are _ in cancer

A

gain of function, loss of function

58
Q

four common types of changes that produces oncogenes

A
  1. missense mutations
  2. gene amplifications
  3. chromosomal translocations (philidel transolation = overexpression of BCR-ABL fusion protein)
  4. viral integration
59
Q

oncogenes often encode…

A
  • growth factor receptors
  • intracellular signaling proteins
  • transcription factors
60
Q

cancer can affect Ras by

A
  • decreasing activity of GTPase
  • increase the rate of exchange of bound GDP for GTP
  • Ras signalling pathway stays on longer than normal
61
Q

Rb protein normally

A

prevents proliferation of cancer cells
* Rb is phosphorylated when cell is about to divide, lets go of E2F that activates genes for cell cycle progression
* when no Rb copies, E2F is always active

62
Q

p53

A
  • makes sure that cell doesnt divide w dna damage
  • activates genes that promote DNA repair
  • arrests cells division (stimulate p21 which inhibits cyclin/CDK complexes)
  • activates apoptosis (activate caspases)
63
Q

two categories of tumor supressor genes

A
  • proteins that negatively regulate cell division (Rb regulates E2F)
  • proteins that maintain genomes integrity
64
Q

3 ways tumor supressor genes can be silenced

A
  • mutation in gene itself (promoter, introduce stop codon)
  • aneuploidy (chromosome loss)
  • epigenetic changes
65
Q

loss of hetrozygosity

A

loss of the functional copy of a gene
* dominant fashion inheritence
* point mutation in normal allelel
* chromosome carrying functional copy is lost

66
Q

epigenetic changes relating to cancer

A
  • DNA methylation
  • covalent modification of histones
  • chromatin remodeling
67
Q

gene pool

A

all the alleles of every gene in a population

68
Q

population

A

group of individuals of the same species that occupy the same region and can interbreed with each other

69
Q

The alpha-globin gene in humans and beta-globin gene in humans can be described as

homologs.
paralogs.
members of a gene family.

A

all of the above

70
Q

A DNA microarray is a slide that is dotted with

A

known sequences of DNA

71
Q

If a computer program is designed to recognize a directional arrangement of bases, such as any inverted repeats in transposable elements, this is an example of

A

pattern recognition

72
Q

For a rare inherited disease, the theoretical concordance for an autosomal dominant disease among fraternal twins is

A

50%

73
Q

Gene X can exist as a normal allele and also as a dominant mutant allele that causes a disease. You purify protein X from a homozygous normal individual and also from an individual that is homozygous for the mutant allele. You have an assay to determine the function of protein X. When you assay 1 mg of the purified protein from a normal homozygote, the activity is 100%. When you mix together 0.5 mg of the normal protein and 0.5 mg of the mutant protein, the activity is 13%. Based on this experiment, why type of dominant mutant is this?

A

dominant negative

74
Q

A pre-disposition to develop breast cancer due to a BRCA-1 mutation displays a _ in a pedigree.

A

dominant inheritance pattern

75
Q

At the cellular level, the BRCA-1 mutation is .

A

recessive

76
Q

The mutation in BRCA-1 that promotes cancer is a

A

loss-of-function mutation.

77
Q

local population

A

smaller groups within populations

78
Q

populations may change in

A
  • size
  • geographic location
  • genetic composition
79
Q

polymorphic

A

gene that exists as 2 or more alleles in a population

80
Q

polymorphisms are often causes by

A

SNPs, a single base pair change in DNA

81
Q

beta globin gene variations

A

SNP that causes sickle cell disease
deletion that eliminates function

82
Q

allele frequency

A

number of allele in pop / total allele in pop

83
Q

genotype frequency

A

number of indi w geneotype / total number of individuals

84
Q

for monomorphic genes, the allele frequency

A

will be equal or close to 1

85
Q

for polymorphic genes, the allele frequency

A

should add up to 1

86
Q

conditions of HW equilibrium

A
  • no new mutations
  • no genetic drift
  • no migration
  • no natural selection
  • random mating
87
Q

chi squared test for HW equalibrium

A

if null hypothesis is not rejected, population in Eq

  • if null hyothesis is rejected, population in disequil
88
Q

microevolution

A

changes in a population’s gene pool from generation to generation

89
Q

microevolution is driven by

list

A
  • mutation
  • random genetic drift
  • migration
  • natural selection
  • non randoming mating
90
Q

_ is the source of new genetic variation

A

mutations

91
Q

_ change allele frequency the most from generation to generation

A

random genetic drift and natural selection

92
Q

genetic drift

A

allele changes as a matter of chance

93
Q

reproductive success

A

the ability to survive to reproductive age in a particular enviroment

94
Q

natural selection acts on

A

phenotypes

which govern by genotype

95
Q

atural selection acts on

A

phenotypes

which govern by genotype

96
Q

principles of natural selection

A
  1. within a population there is allelic variation arising from various factors such as mutations
  2. some alleles may encode proteins that enhance an indiciduals survial or reproductive capacity
  3. idividuals with beneficial alles are more liley to reproduce
  4. allel frequencie s of many different genes may change through natural selection
97
Q

darwinian fitness

A

the relative likelihood that a genotype will survive and contribute to the gene pool of the next generation

98
Q

relative fitness

A
  • gene with highest reproductive sucess is given fitness value of 1
  • other ones are assigned vallues based on how many offspring they make / how many the highest one made
99
Q

list four ways natural selection operates

A
  1. directional selection
  2. balancing selection
  3. disruptive selection
  4. stabalizing selection
100
Q

directional selection

A

favors the extreme phenotype
* switches back in forth between high and low extremem in some populations
* frequency of AA: p2 x highest fitness value
* Aa: 2pq medium fitness
* aa: q2 times lowest fitness value
* add up to mean fitness of the population

101
Q

calculate mean fitness if
A= 0.5
a = 0.5

AA indiv: 5
Aa: 4
aa: 1

A

= (0.52)(1) + (2)(0.5)(0.5)(0.8) + (0.52(0.2)

= 0.25 + 0.4 + 0.05
= 0.7

  • to get frequency after one generation of direction selection, divide each term by 0.7