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bio exam 3 > CH 13 > Flashcards

CH 13 Flashcards

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1
Q

Carl Correns

A

(1900)

first suggests central role for chromosomes

authored one of the scientific papers announcing rediscovery of Mendel’s worl

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2
Q

Walter Sutton

A

(1902)
Chromosomal theory of inheritance

based on observations that similar chromosomes paired with one another during meiosis

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3
Q

T.H. Morgan

A

(1910)
-Working with fruit fly, Drosophila melanogaster
-discovered a mutant male fly with white eyes instead of red
-crossed the mutant male to a normal red-eyed female
-all F1 progeny red eyed= dominant trait

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4
Q

When morgan crossed F1 females with F1 males, what happened in the F2 generation?

A

Contained red and white eyed flies, but all white eyed flies were male

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5
Q

Testcross of a F1 female with a white-eyed male showed what?

A

The viability of white eyed females

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6
Q

What did morgan conclude?

A

eye color gene resides on the female X chromosome

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7
Q

sex linked

A

traits determined by sex chromosome

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8
Q

sex chromosomes

A

a pair of dissimilar chromosomes that still pair during meiosis and mitosis

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9
Q

What is sex determination in Drosophila based on?

A

The number of X chromosomes

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10
Q

XX (Humans)

A

female

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11
Q

XY (humans)

A

male

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12
Q

ZW (birds)

A

female

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13
Q

ZZ (birds)

A

male

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14
Q

XX (grasshoppers)

A

female

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15
Q

XO (grasshoppers)

A

male

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16
Q

diploid (honeybees)

A

female

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17
Q

haploid (honeybees)

A

male

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18
Q

Humans have a total of __ chromosomes

___ are automosomes
___ pair of sex chromosomes

A

46; 22; 1

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19
Q

__ chromosomes is highly condensed

A

Y

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20
Q

recessive alleles on male’s X have no active _____ on Y

A

counterpart

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21
Q

“default” for humans is ____

A

female

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22
Q

In organisms with XY determination, are a lot of genes from the Y chromosome expressed?

A

No, few are

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23
Q

Why can a single recessive sex linked gene produce recessive phenotype?

A

Recessive alleles on X chromosome have no active partner on Y

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24
Q

certain genetic diseases affect males to a ____ degree than females

A

greater

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25
X linked recessive alleles:
red green color blindless hemophilia
26
dosage compensation
ensures equal expression of genes from sex chromosomes even through number of chromosomes is different between sexes
27
In mammalian female cells, 1 X chromosome is randomly inactivated and is highly condensed into a _____ _____
barr body
28
females heterozygous for genes on the X chromosome are ____ ______
genetic mosaics
29
(Chromosome theory exceptions) Mitochondria and chloroplasts contain _____
genes
30
(Chromosome theory exceptions) Traits controlled by these genes do not follow the ____
Chromosomal theory of inheritance
31
(Chromosome theory exceptions) Genes from mitochondria and chloroplasts are often passed to the offspring by only one parent, often the _____, called _____ inheritance
mother; maternal
32
(Chromosome theory exceptions) In plants, chloroplasts are also often inherited from the mother, although this is species _____
dependent
33
(Genetic Mapping) Early geneticists realized that they could obtain information about the ______ between genes on a chromosome
distance
34
(Genetic Mapping) Distance estimates based on ....
patterns of genetic recombination (crossing over) between genes
35
(Genetic Mapping) If crossover occurs, parental alleles are...
recombined, producing recombinant gametes
36
The Creighton and McClintock experiment Hypothesis
Crossing over involves a physical exchange of genetic material
37
The Creighton and McClintock experiment Prediction
Recombination of visible differences in a chromosome should correlate with genetic recombination of alleles
38
The Creighton and McClintock Experiment Test Two visible markers: - - combined with two genetic markers - -
yellow extension; green knob, kernel color, kernel texture
39
The Creighton and McClintock experiment Results
Genetically recombinant progeny also have physically recombinant chromosomes
40
The Creighton and McClintock experiment conclusion
A physical exchange of genetic material accompanied genetic recombination
41
What did Alfred Sturtevant do?
Undergraduate in TH Morgan's lab and put morgan's observation that recombinant progeny reflected relevant location of genes in quantitative terms
42
(Alfred Sturtevant) As physical distance on a chromosome increases...
so does the probability of recombination (crossover) occurring between the gene loci
43
recombination frequency
recombinant progeny/ total progeny
44
If homologues undergo two crossovers between loci...
then the parental combination is restored
45
Multiple crossovers lead to an ____ of the true genetic distance
underestimate
46
Odd numbers of crossover events produce...
recombinant gametes
47
No crossover or even numbers of crossovers produce...
parental gametes
48
Is the relationship between true distance on a chromosome and the recombination frequency linear?
No
49
Crossing over
genetic recombination between non sister chromatids
50
crossing over allows the homologues to exchange....
Chromosomal material
51
in crossing over, alleles of genes that were formerly on separate homologues can now...
be found on the same homologue
52
chiasmata
site of crossing over
53
(three point testcross) uses ___ loci instead of 2 to construct maps
3
54
(three point testcross) middle gene allows ...
tracking of recombination events on either side
55
(three point testcross) in any three point cross, the class offspring with two crossovers is...
the least frequent class
56
(three point testcross) in practice, geneticists use three point crosses to determine ...
the order of genes, then use data from the closes two point crosses to determine distances
57
some genetic disorders affect males more than females, that is ____ ____
sex linked
58
Hemophilia
a disease that affects a single protein in a cascade involved in formation of blood clots
59
For of hemophilia is caused by an ... heterozygous females are ____ ____
X linked recessive allele; asymptomatic carriers
60
Human genetic disorder causes
A single amino acid change in a single protein can result in clinical syndrome
61
Sickle cell anemia
first human disease shown to be the result of a mutation in a protein
62
what is sickle cell anemia caused by?
a defect in the oxygen carrier molecule, hemoglobin leads to impaired oxygen delivery to tissues
63
Homozygotes for sickle cell allele exhibit ....
intermittent illness and reduced life span
64
Heterozygotes in sickle cell anemia appear....
normal, do have hemoglobin with reduced ability
65
Why is sickle cell allele is particularly prevalent in people of African descent
Proportion of heterozygotes higher than expected confers resistance to blood borne parasite that causes malaria, explains higher proportion of allele
66
Nondisjunction
the failure of homologues or sister chromatids to separate properly during meiosis
67
aneuploidy
gain or loss of a chromosome, the result of nondisjunction
68
monosomy
loss
69
trisomy
gain
70
Which autosomes are severe defects and can die within a few months?
13, 15,18
71
Which autosomes can survive to adulthood?
21 and 22
72
Down syndrome
trisomy 21
73
Do nondisjunction of sex chromosomes generally experience severe developmental abnormalities?
No
74
In nondisjunction of sex chromosomes, individuals have somewhat ______ _______ but often reach maturity and in some cases, may be fertile
abnormal features
75
XXX
triple X females
76
XXY
males (Klinefelter syndrome)
77
XO
females (Turner syndrome)
78
OY
nonviable zygotes
79
XYY
males (Jacob syndrome)

bio exam 3 (6 decks)

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