Test 2 Review Flashcards
(178 cards)
1
Q
The dominate allele is the one that occurs in?
A
The heterozygote
2
Q
The Recessive allele is the one that?
A
is the phenotype of the homozygote recessive
3
Q
What are the 5 basic Mendelian pedigree patterns?
A
Autosomal dominant Autosomal recessive X-linked dominant X-linked recessive Y-linked
4
Q
What is a pedigree?
A
a diagram of a family tree showing the phenotype of each indiviudal among a group of relative
5
Q
A half filled in circle on the pedigree indicates?
A
a carrier of disease
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
7
Q
An autosomal dominate disease will alway show a _____________ parent.
A
affected parent
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
9
Q
Why are most people with autosomal dominate diseases heterozygotes?
A
because homozygote dominate embryos individuals don’t survive
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
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
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
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
14
Q
Two affected recessive parents can only have?
A
a affected child
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
16
Q
What type of dominance is this? both alleles are expressed in heterozygote
A
co-dominance
17
Q
What type of dominance is this? The phenotype of heterozygote is intermediate between the phenotypes of homozygous genotypes.
A
Incomplete dominance
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
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)
20
Q
What does the ABO gene encode?
A
ABO gene encodes a glycosyltransferase that catalyzes the transfer of carbohydrates to the H antigen.
21
Q
How many alleles does the ABO gene have?
A
Ia, Ib, Io
22
Q
How are different blood types determined?
A
Different blood types are determined by which antigen galatose is transferred too.
23
Q
What happens to the O allele?
A
a frameshift deletion creates a stop codon which is what happens to the O allele
24
Q
O blood type is a?
A
universal donor
25
AB blood type is a?
universal recipient
26
Allele IA is dominant over \_\_\_. Allele IB is dominant over \_\_\_. Allele __ and ___ are co-dominant
Allele IA is dominant over IO. Allele IB is dominant over IO. Allele IA and IB are co-dominant
27
People who are type A blood produce antibodies against?
People who are type A blood produce antibodies against B antigen (type B and AB blood).
28
People who are type B blood produce antibodies against?
People who are type B blood produce antibodies against A antigen (type A and AB blood).
29
People who are type AB blood produce?
People who are type AB blood produce no antibodies.
30
People who are type O blood produce?
People who are type O blood produce antibodies against A and B antigen (type A and B blood).
31
What is epistasis?
gene-gene interaction that perturbs the normal Medelian ratios
32
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 ?
Ratio is 13 white:13 colored
33
A haploid chromosome has how many chromosomes?
1 (n)
34
A diploid chromosome has how many chromosomes?
2 chromosomes 2n
35
A triploid chromosome has how many chromosomes?
3 chromosomes 3n
36
A trisomy is?
2 (2n+1)
37
a tetraploid is?
4n
38
Monosomy is?
1(2n-1)
39
Mitosis?
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
40
What are the phases of mitosis? Divided into Interphase and Mitotic
Interphase- G1 (gap phase) S (Synthesis) g2 (gap phase 2) Mitotic Phase M (Mitosis) C (cytokinesis)
41
What is the primary growth phase and the longest phase of interphase?
G1 (gap phase 1)
42
Where does the replication of DNA occur?
S phase
43
When do the organelles replicate?
G2 (gap phase 2)
44
When does nuclear division occur, and is the shortest period thats divided into four phases?
Mitosis
45
When does the seperation of 2 cells occur?
cytokinesis
46
Where are the two checkpoints in the cell cycle?
G1/S-located at the end of G1 G2/M-Located at end of G2
47
What occurs at the G1/S checkpoint?
Can DNA synthesis begin ? (Are all DNA in good condition? Is environment favorable ?) Cell “decides” to go (S) or wait (G1)
48
What occurs at the G2/M checkpoint?
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
49
How are enzymes regulated?
cyclin dependent kinase 2
50
What does P21 bind too? and what occurs?
P21 Binds to CDK2 and and will stop cell replication
51
What does DNA damage induce?
P53
52
What does p53 do?
induces the expression of p21, which will bind to CDK and will stop cell replication. It also induces repair of DNA
53
P53 is deleted or inactivated in 50% of people with what?
cancer
54
As p53 levels lower, what occurs?
As p53 levels lower, so will p21 and CDK2 will be reactivated
55
If DNA is not repaired, what does p53 do?
induces programed cell death
56
What type of cells are in the Go phase and what is the Go phase?
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
57
What are the steps of Mitosis (in order)? \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
1)Prophase 2)Metaphase 3)Anaphase 4)telophase
58
What is the difference between S and G2 chromosomes?
G2 phase chromosomes have started to condense
59
When does maximum condensation of chromosomes occur? \*\*\*\*\*\*\*\*\*\*
In metaphase
60
The two copies of a replicated chromosome are termed ?
chromatid
61
Sister chromatids are joined at the middle by a?
Centromere
62
How can you tell where cells are in the replication cycle?
Flow cytometry
63
How does flow cytometry work?
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
64
Meiosis is?
A specialized form of cell division is needed to cut the ploidy by half
65
What cycle does meiosis have that mitosis doesnt?
S phase
66
What are the 5 subsections of Prophase I?
(i) Leptotene (ii) Zygotene (iii) Pachytene (iv) Diplotene (v) Diakinesis.
67
In which subsection of prophase one do the chromosomes become gradually visible (condensed) under the light?
Leptotene
68
What subsection of prophase I does synapsis occur? \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
zygotene
69
The chromosome synapsis is accompanied by the formation of complex structure called
synaptonemal complex
70
What are the complex of a pair of synapsed homologous chromosomes called?
bivalent
71
Bivalent chromosomes=?
4 chromatids (tetrads)
72
Where does crossing over occur?
pachytene
73
Recombination between homologous chromosomes is completed by?
the end of pachytene
74
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?
Diplotene
75
What is the crossover sight called?
chiasma
76
Define: Crossing-over
the physical connection between two chromosomes and following exchange of chromosome segment.
77
Define: Synapsis
the event in which homologous chromosomes recognize each other and then align themselves along their entire lengths.
78
What subsection of Prophase I are the chromosomes fully condensed and the nuclear envelope starts to break down?
Diakinesis
79
What are the Genetic Variation mechanisms of Meiosis
1) crossing over 2) Independent assortment 3)Fertilization
80
Independent assortment is?
The random shuffling that produces over 8.3 million gametes
81
Females are?
homogametic
82
Males are?
heterogametic
83
Males always transmit what chromosome to daughter? \*\*\*\*\*\*\*\*\*\*
`X chromosome
84
Male always receives x chromosome from?
their mother
85
What disease is NEVER passed from father to son?
X linked dominate disease
86
If a affected male (x linked dominate disease) and normal female produce offspring, who will be affected?
only the daughters will be affected
87
If an affected (x linked dominate disease) female and normal male produce offspring what are the chances they will have it?
1/2 for sons and 1/2 for daughters
88
In an x-linked recessive disease requires how many alleles to be affected?
for females, two doses for males, only 1
89
What is the formula for prediction of progeny distributions?
p=(n!/s!t?)(a^s)(b^t)
90
What do each of the symbols mean in this formula? p=(n!/s!t?)(a^s)(b^t)
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
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 ?
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
the probability of crossing over between two genes increases as
as the physical distance between the genes becomes larger. (crossing over increases= distance increases)
93
Parental gametes refer to?
gametes where the arrangement of linked alleles has not been changed
94
Recombinate gametes refers to?
the combination of alleles is NOT found in the original chromosomes
95
recombination frequency =? \*\*\*\*\*\*\*\*\*\*\*\*\*\*
of recombinant gametes/# of total gametes x 100
96
% recombination (% of recombinant gametes) = ? \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
recombination frequency x 100
97
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%).
C. 50%
98
If the probability of cross over between A and B 90%, then what is the recombination frequency?
(18 recombinants/40 gametes) x 100 =% of recombinant gametes =45%
99
Genes on different chromosomes are ___________ assorted. \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
independently
100
Genes on same chromosome have a tendency to? \*\*\*\*\*\*\*\*\*\*\*\*\*\*
stay together (linkage)
101
Genes with recombination frequencies \< \_\_\_\_% are linked and are on the same chromosome. \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
50%
102
Genes with recombination frequencies ~\_\_\_\_% are completely linked. They are on the same chromosome and inherited as a unit. \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
0%
103
Genes that have a recombination frequency of \_\_\_% (independent assortment) are unlinked. \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
50%
104
Define- Synteny:
A group of genes present in the same chromosome regardless of whether they show independent assortment or linkage.
105
What is a genetic Map?
Diagram of the linear order of genes
106
Distance between two genes can be represented in four ways: What are they?
(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
•A diagram of the order of genes in a chromosome in which the distance between adjacent genes is proportional to?
the rate of recombination between them.
108
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
(4) y-cv-rb
109
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 ?
4-will have crossover-
(2x4)=8 recombinates= 2%
400 gametes
96-will not have crossver
110
1% recombination has what percentageof meiotic cells having one crossover?
(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
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?
Recombination frequency = # recombinants/total (100) = 85 +75/85 +75 + 728 + 712 = 0.1(100) = 10%
112
# Define
Linkage group
group of genes, each of which is linked (r \< 0.5) to at least one other
113
maximum map distance is?
50
114
What is the formula for map distance?
Map distance (cM)=(1/2) x Average number of crossovers in the region per meiotic cell x 100
115
Map distance measures?
how much crossing over takes place between the genes
116
The recombination frequency reflects?
how much recombination actually is observed
pg. 162
117
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
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
In any genetic crosses # of recombinate gametes for two linked genes is less?
\*\*\*\*\*\*\*
than the nuber of parental gametes
119
What is trans (repulsion) configuration?
mutant alleles are in opposite chromosomes
120
What is cis configuration?
mutant alleles are in same chromosomes
121
What is a 3 point test cross?
C
A---l----B
^Distance
Between A-C + Dis
Between C-B
122
•When two genes are located far apart along a chromosome, more than?
one crossover can occur
123
Double crossovers between two loci will restore
the parental genotype
Double crossovers are sort of like a double negative
124
For genes that are distance along a chromosome in a triple crossover, true map distance is estimates by?
summing the recombination frequencies across shorter intervals
125
As map distance increases, what declines?
accuracy of map distances
126
A three point cross provides what (in concern to mapping)?
faster and more accurate mapping
127
Probability of no crossover ___ single crossover ___ double crossover
Probability of no crossover\> single crossover\> double crossover
128
Double cross over results in ?
Double cross over results in interchange of a middle pair of allele
129
# Define:
Chromosome interference
crossovers in one region decrease the probability of a second crossover close by
130
# Define:
Coefficient of coincidence
observed number of double recombinants divided by the expected number
131
Interference =?
Interference = 1-Coefficient of coincidence
132
A human female has a higher?
recombination frequencu than a male
133
Cross over is a function of \_\_\_\_\_\_\_\_\_\_\_\_which is a function of \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
Cross over is a function of chromosome cleavage which is a function of physical distance
134
The map distance and the ___________ between genes usually correlate but this is?
The map distance and the physical distance between genes usually correlate, but this is not always absolute
135
Genetic map distance is a function of?
recombination frequency
136
If a male fly has no crossover, what is the map distance?
0
137
Hypotheses of DNA replication
What is semi conservative DNA replication?
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
Hypotheses of DNA replication
How does the semi-conservative model of DNA work?
Conservative Model-DNA stays together all the time.
139
Hypotheses of DNA replication
How does the dispersive model work?
•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
How did the Meselson and Stahl experiment work?
* 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
What did the Meselson and Stahl experiment prove?
That the semi conservative model was how DNA replication actually worked
142
Which model was immediatly rejected by the Meselson and Stahl Experiment? Why?
Because there was only one species of of the N15 in the test tube
143
Why was the conservative model proven wrong by the Meselson and Stahl experiment?
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
# Define:
Theta replication
•circular DNA, E. coli; single origin of replication forming a replication fork, usually a bidirectional replication
145
# Define:
Rolling-circle replication
•some bacterophages and viruses, F factor of E. coli; single origin of replication
146
Theta replication normally occurs in?
most bacteria
147
Theta replication is also called ____________ DNA synthesis.
Theta replication is also called bi-directional DNA synthesis.
148
What is the Replication fork in Theta replication?
Replication fork – point where two strands separate
149
What uses the Rolling circle replication?
Bacteriophages and some virsesn
150
How does rolling circle replication begin?
with a nick at the origin of replication
151
What cleaves the nick in DNA in Rolling circle and creates what?
It is cleaved with a nuclease, and this creates 5' to 3'
152
Where is new DNA created in rolling circle?
New DNA is created on 3' end and matches the inner circle
153
Rolling circle-
At the end of DNA replication, there is new?
DNA synthesis to create double stranded DNA (using single stranded as a temp)
154
Eukaryotic chromosomes use what method of replication?
linear
155
Linear replication has many \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
linear replication has many origins of replication.
156
Linear Replication-
When does linear replication start?
When DNA at the origin of replication denatures to expose the bases creating a replication fork
157
Linear Replication-
During the first step in replication, what is the first protien that binds to DNA inducing local unwinding?
DNA A
158
Linear Replication-
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ protien binds to single stranded DNA and stablize the open configuration.
\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
Single Stranded binding (SSB) protien
159
Linear Replication-
Dna A binding facilitates what?
Dna A facilitates subsequent binding of Dna B (helicase) and Dna C protien, resulting in further unwinding
160
Linear Replication-
Helicase requires?
ATP to break the hydrogen bonds of DNA
161
Linear Replication-
The DNA unwinding results in supercoiling which is removed by?
the enzyme gyrase
162
Linear Replication-
What synthesizes a short (5-10nt) RNA primer?
DNA primase (Dna G)
163
DNA polymerase I does what?
Creates RNA primer
164
Who proved that there were additional DNA polymerases?
How?
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
What else did the discovery of the mutant strain by John Cairns and Paula deLucia show?
DNA pol I is NOT the principal replication enzyme in E. coli
166
DNA polymerase I is responsible for not only the RNA primer but also-
Removes the primer and repairs DNA
167
DNA polymerase II. IV, and V are responsible for?
DNA repair
168
DNA polymerase III is responsible for?
5' to 3' polymerization for in vivo replication, and also involved in replication of bacterial chromosome
169
What was the "real" polymerase in E. coli?
DNA polymerase III
170
5’ to 3’ exonuclease activity is unique to \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
3’ to 5’ exonuclease activity is common to \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
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
3’à5’ exonuclease activity does what in DNA replication?
3’à5’ exonuclease activity to remove misincorporated nucleotides from 3’ end of DNA (proofreading).
172
5’à3’ exonuclease activity during DNA replication is for?
5’à3’ exonuclease activity to remove an RNA primer.
173
DNA Polymerase I-
Cleavage of the 5' to 3' exonuclease creates what?
The Klenow Fragment
174
What is contained in the Klenow Fragment?
\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
3' to 5' exonuclease and polymerase
175
- ____________ degrades single-stranded DNA from the 3’ end
- ________________ degrades base paired DNA from the 5’ terminus
- \_\_\_\_\_\_\_\_\_\_\_\_\_\_adds nucleotides
- 3’ exonuclease degrades single-stranded DNA from the 3’ end
- 5’ exonuclease degrades base paired DNA from the 5’ terminus
- polymerase adds nucleotides
176
DNA elongation-
What adds nucleotides to the 3' end?
DNA polymerase III
177
If DNA strands are extended 5' to 3', how can the antiparallel strand by simultaneously replicated past the replication fork?
Okazaki fragments
178
DNA elongation-
How is DNA elongated in the 3' to 5' direction? Explain
short RNA primers are formed by RNA polymerase.
The RNA primer is then degraded by 5'-3'
