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Test 2 Review Flashcards

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1
Q

The dominate allele is the one that occurs in?

A

The heterozygote

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2
Q

The Recessive allele is the one that?

A

is the phenotype of the homozygote recessive

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3
Q

What are the 5 basic Mendelian pedigree patterns?

A

Autosomal dominant Autosomal recessive X-linked dominant X-linked recessive Y-linked

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4
Q

What is a pedigree?

A

a diagram of a family tree showing the phenotype of each indiviudal among a group of relative

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5
Q

A half filled in circle on the pedigree indicates?

A

a carrier of disease

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6
Q

A man who has achondroplasia (an autosomal dominant disease) marries a phenotypically normal woman. If they have four children, what is the probability that none of their children will be affected with this disorder ? What is the probability that all of children will be affected ?

A

50% of children will be affected, because Hh (affected man) hh(normal woman) H h h b/c of that the genotypes will be either Hh or hh so 4 children- 1st 2nd 3rd 4th 1/2 x 1/2 x 1/2 x 1/2 = 1/16

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7
Q

An autosomal dominate disease will alway show a _____________ parent.

A

affected parent

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8
Q

How can you tell if a disease is x or y linked or autosomal from a pedigree?

A

if both males and females are affected it is autosomal. if it is only females it is x linked if it is only males it is y linked

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9
Q

Why are most people with autosomal dominate diseases heterozygotes?

A

because homozygote dominate embryos individuals don’t survive

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10
Q

What is the probability of disease in children of homozygous recessive diseases?

A

1/4 b/c RR (normal) x rr (disease) RR Rr Rr rr so only 1 in 4 will be a carrier

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11
Q

Is it a dominant pedigree or a recessive pedigree? If two unaffected people have an affected child, it is a dominant or recessive pedigree:

A

Recessive

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12
Q

Is it a dominant pedigree or a recessive pedigree? If every affected person has an affected parent it is a dominant or recessive pedigree.

A

dominate

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13
Q

Is it a dominate or recessive pedigree? If two affected people have an unaffected child, it is a dominant or recessive pedigree:

A

dominate

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14
Q

Two affected recessive parents can only have?

A

a affected child

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15
Q

What type of dominance is this? one allele completely overwhelm or does not allow the other allele’s effect to be shown

A

dominant

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16
Q

What type of dominance is this? both alleles are expressed in heterozygote

A

co-dominance

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17
Q

What type of dominance is this? The phenotype of heterozygote is intermediate between the phenotypes of homozygous genotypes.

A

Incomplete dominance

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18
Q

Although a population of organisms may contain any number of alleles, any particular organism or cell can not carry more than ___ alleles (individuals have only two biological parents), and any gamete can not carry more than ___ allele

A

Although a population of organisms may contain any number of alleles, any particular organism or cell can not carry more than two alleles (individuals have only two biological parents), and any gamete can not carry more than one allele

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19
Q

What is the formula for figuring out genotypes?

A

n(n+1)/2 ex. Gene with 2 alleles can generate 3 genotypes (AA, Aa, aa) Genes with 3 alleles can generate 6 genotypes (B1B1, B1B2, B1B3, B2B2, B2B3, B3B3) Genes with 4 alleles can generate 10 genotypes (4 x (4+1))/2 = 10, C1C1, C1C2, C1C3, C1C4…C4C4) Genes with 10 alleles can generate 55 genotypes (D1D1, D1D2, D1D3,………D10D10)

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20
Q

What does the ABO gene encode?

A

ABO gene encodes a glycosyltransferase that catalyzes the transfer of carbohydrates to the H antigen.

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21
Q

How many alleles does the ABO gene have?

A

Ia, Ib, Io

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22
Q

How are different blood types determined?

A

Different blood types are determined by which antigen galatose is transferred too.

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23
Q

What happens to the O allele?

A

a frameshift deletion creates a stop codon which is what happens to the O allele

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24
Q

O blood type is a?

A

universal donor

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25
Q

AB blood type is a?

A

universal recipient

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26
Q

Allele IA is dominant over ___. Allele IB is dominant over ___. Allele __ and ___ are co-dominant

A

Allele IA is dominant over IO. Allele IB is dominant over IO. Allele IA and IB are co-dominant

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27
Q

People who are type A blood produce antibodies against?

A

People who are type A blood produce antibodies against B antigen (type B and AB blood).

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28
Q

People who are type B blood produce antibodies against?

A

People who are type B blood produce antibodies against A antigen (type A and AB blood).

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29
Q

People who are type AB blood produce?

A

People who are type AB blood produce no antibodies.

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30
Q

People who are type O blood produce?

A

People who are type O blood produce antibodies against A and B antigen (type A and B blood).

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31
Q

What is epistasis?

A

gene-gene interaction that perturbs the normal Medelian ratios

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32
Q

In domesticated chickens, a dominant allele C is required for colored feathers, but a dominant allele I of an unlinked gene is an inhibitor of color that overrides the effects of C. White Leghorns have genotype CC II whereas White Wyandottes have genotype cc ii. Both breeds are white, but for different reasons. In the F2 generation of a cross between White Leghorns and White Wyandottes, what is the phenotypic ratio of white: colored ?

A

Ratio is 13 white:13 colored

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33
Q

A haploid chromosome has how many chromosomes?

A

1 (n)

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34
Q

A diploid chromosome has how many chromosomes?

A

2 chromosomes 2n

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35
Q

A triploid chromosome has how many chromosomes?

A

3 chromosomes 3n

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36
Q

A trisomy is?

A

2 (2n+1)

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37
Q

a tetraploid is?

A

4n

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38
Q

Monosomy is?

A

1(2n-1)

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39
Q

Mitosis?

A

A form of cell division by which two daughter cells are produced from a parental cell A nuclear division through which a daughter cell receives the same set of chromosomes as the parental cell

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40
Q

What are the phases of mitosis? Divided into Interphase and Mitotic

A

Interphase- G1 (gap phase) S (Synthesis) g2 (gap phase 2) Mitotic Phase M (Mitosis) C (cytokinesis)

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41
Q

What is the primary growth phase and the longest phase of interphase?

A

G1 (gap phase 1)

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42
Q

Where does the replication of DNA occur?

A

S phase

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43
Q

When do the organelles replicate?

A

G2 (gap phase 2)

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44
Q

When does nuclear division occur, and is the shortest period thats divided into four phases?

A

Mitosis

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45
Q

When does the seperation of 2 cells occur?

A

cytokinesis

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46
Q

Where are the two checkpoints in the cell cycle?

A

G1/S-located at the end of G1 G2/M-Located at end of G2

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47
Q

What occurs at the G1/S checkpoint?

A

Can DNA synthesis begin ? (Are all DNA in good condition? Is environment favorable ?) Cell “decides” to go (S) or wait (G1)

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48
Q

What occurs at the G2/M checkpoint?

A

Check if DNA replication and repair of any DNA damage is completed before mitosis (Has DNA synthesis been completed correctly?) Cell makes a commitment to mitosis

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49
Q

How are enzymes regulated?

A

cyclin dependent kinase 2

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50
Q

What does P21 bind too? and what occurs?

A

P21 Binds to CDK2 and and will stop cell replication

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51
Q

What does DNA damage induce?

A

P53

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52
Q

What does p53 do?

A

induces the expression of p21, which will bind to CDK and will stop cell replication. It also induces repair of DNA

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53
Q

P53 is deleted or inactivated in 50% of people with what?

A

cancer

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54
Q

As p53 levels lower, what occurs?

A

As p53 levels lower, so will p21 and CDK2 will be reactivated

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55
Q

If DNA is not repaired, what does p53 do?

A

induces programed cell death

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56
Q

What type of cells are in the Go phase and what is the Go phase?

A

liver, muscle and nerve cells are in this phase. They are ‘retired cells’ and will not divide again *note: liver cells have the capacity to be regenerated if damage occurs

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57
Q

What are the steps of Mitosis (in order)? *****************

A

1)Prophase 2)Metaphase 3)Anaphase 4)telophase

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58
Q

What is the difference between S and G2 chromosomes?

A

G2 phase chromosomes have started to condense

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59
Q

When does maximum condensation of chromosomes occur? **********

A

In metaphase

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60
Q

The two copies of a replicated chromosome are termed ?

A

chromatid

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61
Q

Sister chromatids are joined at the middle by a?

A

Centromere

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62
Q

How can you tell where cells are in the replication cycle?

A

Flow cytometry

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63
Q

How does flow cytometry work?

A

DNA in cells can be stained with a fluorescent dye DNA probes like Propidium Iodide are STOICHIOMETRIC (i.e. staining intensity is proportional to amount of DNA, so we can measure how much DNA is in a cell) Cells are injected into a flowing stream of saline solution Signal from an individual cell is collected for analysis as they pass through a laser Data displayed as events on histograms/dot plots

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64
Q

Meiosis is?

A

A specialized form of cell division is needed to cut the ploidy by half

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65
Q

What cycle does meiosis have that mitosis doesnt?

A

S phase

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66
Q

What are the 5 subsections of Prophase I?

A

(i) Leptotene (ii) Zygotene (iii) Pachytene (iv) Diplotene (v) Diakinesis.

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67
Q

In which subsection of prophase one do the chromosomes become gradually visible (condensed) under the light?

A

Leptotene

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68
Q

What subsection of prophase I does synapsis occur? ***************

A

zygotene

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69
Q

The chromosome synapsis is accompanied by the formation of complex structure called

A

synaptonemal complex

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70
Q

What are the complex of a pair of synapsed homologous chromosomes called?

A

bivalent

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71
Q

Bivalent chromosomes=?

A

4 chromatids (tetrads)

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72
Q

Where does crossing over occur?

A

pachytene

73
Q

Recombination between homologous chromosomes is completed by?

A

the end of pachytene

74
Q

What subsection of prophase I does the synaptonemal complex dissolve and the homologous chromosomes in the bivalents are seperated from each other except at the sight of the crossovers?

A

Diplotene

75
Q

What is the crossover sight called?

A

chiasma

76
Q

Define: Crossing-over

A

the physical connection between two chromosomes and following exchange of chromosome segment.

77
Q

Define: Synapsis

A

the event in which homologous chromosomes recognize each other and then align themselves along their entire lengths.

78
Q

What subsection of Prophase I are the chromosomes fully condensed and the nuclear envelope starts to break down?

A

Diakinesis

79
Q

What are the Genetic Variation mechanisms of Meiosis

A

1) crossing over 2) Independent assortment 3)Fertilization

80
Q

Independent assortment is?

A

The random shuffling that produces over 8.3 million gametes

81
Q

Females are?

A

homogametic

82
Q

Males are?

A

heterogametic

83
Q

Males always transmit what chromosome to daughter? **********

A

`X chromosome

84
Q

Male always receives x chromosome from?

A

their mother

85
Q

What disease is NEVER passed from father to son?

A

X linked dominate disease

86
Q

If a affected male (x linked dominate disease) and normal female produce offspring, who will be affected?

A

only the daughters will be affected

87
Q

If an affected (x linked dominate disease) female and normal male produce offspring what are the chances they will have it?

A

1/2 for sons and 1/2 for daughters

88
Q

In an x-linked recessive disease requires how many alleles to be affected?

A

for females, two doses for males, only 1

89
Q

What is the formula for prediction of progeny distributions?

A

p=(n!/s!t?)(a^s)(b^t)

90
Q

What do each of the symbols mean in this formula? p=(n!/s!t?)(a^s)(b^t)

A

n = total number of events, s = number of times outcome a occurs, t = number of times outcome b occurs; a and b are probabilities of two possible outcomes

91
Q

A mating between two heterozygous parents will yield 3:1 ratio of the dominant and recessive traits among sibships of a particular size. How often families with eight children contain exactly six children with dominant phenotype and two with the recessive phenotype ?

A

n = 8, s = 6, t = 2 p = 3/4, q = 1/4 In 31 percent of the families with eight children would have the offspring exhibit the expected 3:1 phenotypic ratio. Slide 55 of the power point has explanation

92
Q

the probability of crossing over between two genes increases as

A

as the physical distance between the genes becomes larger. (crossing over increases= distance increases)

93
Q

Parental gametes refer to?

A

gametes where the arrangement of linked alleles has not been changed

94
Q

Recombinate gametes refers to?

A

the combination of alleles is NOT found in the original chromosomes

95
Q

recombination frequency =? **************

A

of recombinant gametes/# of total gametes x 100

96
Q

% recombination (% of recombinant gametes) = ? ******************

A

recombination frequency x 100

97
Q

The maximum recombination frequency between two genes is A. 1 (100%). B. 0.8 (80%). C. 0.5 (50%). D. 0.1 (10%). E. 0.01 (1%).

A

C. 50%

98
Q

If the probability of cross over between A and B 90%, then what is the recombination frequency?

A

(18 recombinants/40 gametes) x 100 =% of recombinant gametes =45%

99
Q

Genes on different chromosomes are ___________ assorted. *****************

A

independently

100
Q

Genes on same chromosome have a tendency to? **************

A

stay together (linkage)

101
Q

Genes with recombination frequencies < ____% are linked and are on the same chromosome. *****************

A

50%

102
Q

Genes with recombination frequencies ~____% are completely linked. They are on the same chromosome and inherited as a unit. *********************

A

0%

103
Q

Genes that have a recombination frequency of ___% (independent assortment) are unlinked. ***********************

A

50%

104
Q

Define- Synteny:

A

A group of genes present in the same chromosome regardless of whether they show independent assortment or linkage.

105
Q

What is a genetic Map?

A

Diagram of the linear order of genes

106
Q

Distance between two genes can be represented in four ways: What are they?

A

(i) Map unit
(ii) Percent recombination
(iii) Centimorgans (cM)
(iv) Frequency of recombination

1 map unit = 1 percent recombination= 1 centi-morgan (cM) = 0.01 frequency of recombination

107
Q

•A diagram of the order of genes in a chromosome in which the distance between adjacent genes is proportional to?

A

the rate of recombination between them.

108
Q

The genes are all in the X chromosome of Drosophila: y (yellow body), rb (ruby eye), and cv (shortened wing crossvein).

The % recombination between genes y and rb is 7.5 percent.

The % recombination between genes rb and cv is 6.2 percent.

The % recombination between genes y and cv is 1.3 percent.

What is the correct order of genes?

(1) rb-y-cv
(2) y-rb-cv
(3) cv-rb-y
(4) y-cv-rb

A

(4) y-cv-rb

109
Q

5.3 Two linked genes are separated by a distance such that exactly 4 percent of the cells undergoing meiosis have one cross-over between the genes and 96 percent have no crossover. What is the percent recombination between the genes ?

A

4-will have crossover-

(2x4)=8 recombinates= 2%

400 gametes

96-will not have crossver

110
Q

1% recombination has what percentageof meiotic cells having one crossover?

A

(i) 1 crossover generates 2 recombinants.
(ii) 1 percent recombinants = 2 recombinants/ 200 total
(iii) Meiosis produces 4 haploid cells (gametes)

Therefore, 50 cells underwent meiosis (200/4=50).

(iv) therefore, 1 (cross-over)/50 (meiotic cells)= 2%

111
Q

You are doing a genetics experiment with the fruit fly. In the “P” generation, you cross two true-breeding (homozygote) flies. The female parent is brown and wingless and the male parent is black with normal wings. All of the flies in the F1 generation are brown and have normal wings. The color alleles (“B” and “b”) and the wing alleles (“N” and “n”) are linked. You took an F1 female and cross her to a true-breeding black, wingless male. When you count the F2 generation, you got: 85 brown winged flies, 728 black winged flies, 712 brown wingless flies, and 75 black wingless flies. What is the genetic distance between the color and wing genes?

A

Recombination frequency = # recombinants/total (100) = 85 +75/85 +75 + 728 + 712 = 0.1(100) = 10%

112
Q

Define

Linkage group

A

group of genes, each of which is linked (r < 0.5) to at least one other

113
Q

maximum map distance is?

A

50

114
Q

What is the formula for map distance?

A

Map distance (cM)=(1/2) x Average number of crossovers in the region per meiotic cell x 100

115
Q

Map distance measures?

A

how much crossing over takes place between the genes

116
Q

The recombination frequency reflects?

A

how much recombination actually is observed

pg. 162

117
Q

An individual has the genotype Ab/aB. Gene loci (A) and (B) are 15 cM apart. Indicate all the possible gametes this individual can produce, and the proportions of expected progeny genotypes if a testcross is performed on this individual.

A—————-b

a—————–B

A

Gene a and b are linked.

If no recombination, Ab and aB gametes are parental gametes

If crossover, then ab and AB are recombinate gametes

15cm=15 map unit and 15% recombination

  • > 15 Percent of gametes will be recombinate gametes
    7. 5% Will be ab and 7.5% will be AB

Remaining 85% will be the parental gametes

118
Q

In any genetic crosses # of recombinate gametes for two linked genes is less?

*******

A

than the nuber of parental gametes

119
Q

What is trans (repulsion) configuration?

A

mutant alleles are in opposite chromosomes

120
Q

What is cis configuration?

A

mutant alleles are in same chromosomes

121
Q

What is a 3 point test cross?

A

C

A—l—-B

^Distance

Between A-C + Dis

Between C-B

122
Q

•When two genes are located far apart along a chromosome, more than?

A

one crossover can occur

123
Q

Double crossovers between two loci will restore

A

the parental genotype

Double crossovers are sort of like a double negative

124
Q

For genes that are distance along a chromosome in a triple crossover, true map distance is estimates by?

A

summing the recombination frequencies across shorter intervals

125
Q

As map distance increases, what declines?

A

accuracy of map distances

126
Q

A three point cross provides what (in concern to mapping)?

A

faster and more accurate mapping

127
Q

Probability of no crossover ___ single crossover ___ double crossover

A

Probability of no crossover> single crossover> double crossover

128
Q

Double cross over results in ?

A

Double cross over results in interchange of a middle pair of allele

129
Q

Define:

Chromosome interference

A

crossovers in one region decrease the probability of a second crossover close by

130
Q

Define:

Coefficient of coincidence

A

observed number of double recombinants divided by the expected number

131
Q

Interference =?

A

Interference = 1-Coefficient of coincidence

132
Q

A human female has a higher?

A

recombination frequencu than a male

133
Q

Cross over is a function of ____________which is a function of ______________.

A

Cross over is a function of chromosome cleavage which is a function of physical distance

134
Q

The map distance and the ___________ between genes usually correlate but this is?

A

The map distance and the physical distance between genes usually correlate, but this is not always absolute

135
Q

Genetic map distance is a function of?

A

recombination frequency

136
Q

If a male fly has no crossover, what is the map distance?

A

0

137
Q

Hypotheses of DNA replication

What is semi conservative DNA replication?

A

Based on unwinding of DNA into single strand DNA

Scientists thought that the was wrong b/c the long single stranded DNA would get tangled (THIS IS HOW IT ACTUALLY DOES WORK)

138
Q

Hypotheses of DNA replication

How does the semi-conservative model of DNA work?

A

Conservative Model-DNA stays together all the time.

139
Q

Hypotheses of DNA replication

How does the dispersive model work?

A

•Dispersive model was that dsDNA might fragment, replicate dsDNA, and then reassemble, creating a mosaic of old and new dsDNA regions in each new chromosome.

140
Q

How did the Meselson and Stahl experiment work?

A
  • N14 common form; N15 rare heavy form
  • E. coli were grown in a N15 media first, then transferred to N14 media.
  • DNA from cultured E. coli were subjected to equilibrium density gradient centrifugation.
  • Equilibrium density gradient centrifugation

: Heavy salt solution used to measure substances’ densities.

Denser molecules are lower in tube

141
Q

What did the Meselson and Stahl experiment prove?

A

That the semi conservative model was how DNA replication actually worked

142
Q

Which model was immediatly rejected by the Meselson and Stahl Experiment? Why?

A

Because there was only one species of of the N15 in the test tube

143
Q

Why was the conservative model proven wrong by the Meselson and Stahl experiment?

A

Does not fit conservative model, because after one generation there is a single intermediate band, rather than one with entirely 15N DNA and another with entirely 14N DNA

144
Q

Define:

Theta replication

A

•circular DNA, E. coli; single origin of replication forming a replication fork, usually a bidirectional replication

145
Q

Define:

Rolling-circle replication

A

•some bacterophages and viruses, F factor of E. coli; single origin of replication

146
Q

Theta replication normally occurs in?

A

most bacteria

147
Q

Theta replication is also called ____________ DNA synthesis.

A

Theta replication is also called bi-directional DNA synthesis.

148
Q

What is the Replication fork in Theta replication?

A

Replication fork – point where two strands separate

149
Q

What uses the Rolling circle replication?

A

Bacteriophages and some virsesn

150
Q

How does rolling circle replication begin?

A

with a nick at the origin of replication

151
Q

What cleaves the nick in DNA in Rolling circle and creates what?

A

It is cleaved with a nuclease, and this creates 5’ to 3’

152
Q

Where is new DNA created in rolling circle?

A

New DNA is created on 3’ end and matches the inner circle

153
Q

Rolling circle-

At the end of DNA replication, there is new?

A

DNA synthesis to create double stranded DNA (using single stranded as a temp)

154
Q

Eukaryotic chromosomes use what method of replication?

A

linear

155
Q

Linear replication has many ______________.

A

linear replication has many origins of replication.

156
Q

Linear Replication-

When does linear replication start?

A

When DNA at the origin of replication denatures to expose the bases creating a replication fork

157
Q

Linear Replication-

During the first step in replication, what is the first protien that binds to DNA inducing local unwinding?

A

DNA A

158
Q

Linear Replication-

___________________________ protien binds to single stranded DNA and stablize the open configuration.

*******************

A

Single Stranded binding (SSB) protien

159
Q

Linear Replication-

Dna A binding facilitates what?

A

Dna A facilitates subsequent binding of Dna B (helicase) and Dna C protien, resulting in further unwinding

160
Q

Linear Replication-

Helicase requires?

A

ATP to break the hydrogen bonds of DNA

161
Q

Linear Replication-

The DNA unwinding results in supercoiling which is removed by?

A

the enzyme gyrase

162
Q

Linear Replication-

What synthesizes a short (5-10nt) RNA primer?

A

DNA primase (Dna G)

163
Q

DNA polymerase I does what?

A

Creates RNA primer

164
Q

Who proved that there were additional DNA polymerases?

How?

A

John Cairns and Paula deLucia

They isolated a mutant bacterial strain with only 1% DNA polymerase I activity.

This mutant was sensitive to UV radiation but otherwise was fine

165
Q

What else did the discovery of the mutant strain by John Cairns and Paula deLucia show?

A

DNA pol I is NOT the principal replication enzyme in E. coli

166
Q

DNA polymerase I is responsible for not only the RNA primer but also-

A

Removes the primer and repairs DNA

167
Q

DNA polymerase II. IV, and V are responsible for?

A

DNA repair

168
Q

DNA polymerase III is responsible for?

A

5’ to 3’ polymerization for in vivo replication, and also involved in replication of bacterial chromosome

169
Q

What was the “real” polymerase in E. coli?

A

DNA polymerase III

170
Q

5’ to 3’ exonuclease activity is unique to ______________.

3’ to 5’ exonuclease activity is common to __________________________.

A

5’ to 3’ exonuclease activity is unique to DNA polymerase I.

3’ to 5’ exonuclease activity is common to DNA polymerase I , II, and III

171
Q

3’à5’ exonuclease activity does what in DNA replication?

A

3’à5’ exonuclease activity to remove misincorporated nucleotides from 3’ end of DNA (proofreading).

172
Q

5’à3’ exonuclease activity during DNA replication is for?

A

5’à3’ exonuclease activity to remove an RNA primer.

173
Q

DNA Polymerase I-

Cleavage of the 5’ to 3’ exonuclease creates what?

A

The Klenow Fragment

174
Q

What is contained in the Klenow Fragment?

***************

A

3’ to 5’ exonuclease and polymerase

175
Q
  • ____________ degrades single-stranded DNA from the 3’ end
  • ________________ degrades base paired DNA from the 5’ terminus
  • ______________adds nucleotides
A
  • 3’ exonuclease degrades single-stranded DNA from the 3’ end
  • 5’ exonuclease degrades base paired DNA from the 5’ terminus
  • polymerase adds nucleotides
176
Q

DNA elongation-

What adds nucleotides to the 3’ end?

A

DNA polymerase III

177
Q

If DNA strands are extended 5’ to 3’, how can the antiparallel strand by simultaneously replicated past the replication fork?

A

Okazaki fragments

178
Q

DNA elongation-

How is DNA elongated in the 3’ to 5’ direction? Explain

A

short RNA primers are formed by RNA polymerase.

The RNA primer is then degraded by 5’-3’

Genetics (4 decks)

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