Download Genetics I Name: Date: 1. Which represents the genotype of a

Genetics I
Name:
1.
Which represents the genotype of a homozygous condition?
A.
2.
Date:
B.
Bb
C.
BC
D. bc
bb
Gregor Mendel developed some basic principles of heredity based on his
A.
dissection of the owers of both tall and short African violet plants
B.
microscopic observation of the nuclei of fruit y cells
C.
biochemical analysis of DNA produced in the F2 generations of roan cattle
D. mathematical analysis of the o spring produced by crossing pea plants
3.
4.
Hereditary information for most traits is generally located in
A.
genes found on chromosomes
B.
C.
the mitochondria of gametes
D. the lysosomes in the cytoplasm
In pea plants, the gene for tallness (T) is dominant over the gene for shortness (t). If 100% of the F1 generation
o spring are heterozygous tall, what were the most probable genotypes of the parent plants?
A.
5.
chromosomes found on genes
Tt
Tt
B.
Tt
C.
tt
TT
Tt
D. TT
tt
In cabbage butter ies, white color (W) is dominant and yellow color (w) is recessive. If a pure white cabbage
butter y mates with a yellow cabbage butter y, all the resulting (F1 ) butter ies are heterozygous white. Which
cross represents the genotypes of the parent generation?
A.
Ww
ww
B.
WW
C.
Ww
page 1
WW
ww
D. WW
Ww
Genetics I
6.
A cross between two tall garden pea plants produced 314 tall plants and 98 short plants. The genotypes of the tall
parent plants were most likely
A.
7.
C.
Tt and Tt
D. TT and TT
homozygous
B.
heterozygous
C.
pure recessive
D. pure dominant
100%
B.
75%
C.
50%
D. 25%
In guinea pigs, black coat color (B) is dominant over white coat color (b). When two black guinea pigs were
mated, the ratio of black-coated o spring to white-coated o spring was 3 : 1. In this cross, the parental genotypes
were most likely
A.
10.
TT and Tt
When two organisms that are heterozygous for a trait are crossed, and percentage of o spring expected to show the
recessive trait would most likely be
A.
9.
B.
In pea plants, the allele for tallness is dominant over the allele for shortness. Tall pea plants are crossed with short
pea plants, and the cross results in 271 tall plants and 268 short plants. Based on this cross the genotype of the
parental tall pea plants can be correctly described as
A.
8.
TT and tt
Bb
Bb
B.
BB
C.
bb
Bb
bb
D. BB
Bb
If heterozygous black guinea pigs are mated with each other, what percentage of the o spring will be expected to
have the same genotype for coat color as their parents
A.
100%
B.
75%
C.
page 2
50%
D. 0%
Genetics I
11.
The diagram shown represents a pair of homologous chromosomes. Which allelic combination represents the
heterozygous condition for a trait?
A.
12.
B.
Aa
C.
BB
D. aB
AB
TTYY
B.
Ttyy
C.
ttYy
D. TtYy
Symbol
for Gene
T
t
Y
y
B
B
Trait
Represented
tall
short
yellow
green
Two mice that are heterozygous for black coat color are mated. Assuming coat color in mice is controlled by a
single pair of genes, which genotypic ratio for coat color is expected in the o spring?
A.
14.
a
The chart shown indicates a method of representing traits in pea plants. Some o spring of a cross in pea plants
were tall and green. According to the chart, these plants could be represented by
A.
13.
A
1:2:1
B.
9:7
C.
3:1
D. 1 : 3 : 1
In chickens, rose comb (R) is dominant over single comb (r). When a heterozygous rose-combed rooster is mated
with several single-combed hens, what is the expected phenotypic ratio of the o spring?
A.
100% rose-combed
B.
C.
75% rose-combed and 25% single-combed
D. 50% rose-combed and 50% single-combed
page 3
100% single-combed
Genetics I
15.
In minks, the gene for brown fur (B) is dominant over the gene for silver fur (b). Which set of genotypes
represents a cross that could produce o spring with silver fur from parents that both have brown fur?
A.
16.
BB
C.
bb
BB
Bb
D. Bb
bb
0
B.
50
C.
100
D. 200
GG
Gg
B.
GG
C.
GG
Gg
gg
D. gg
gg
In a certain species of mice, brown fur is dominant over white fur and long tails are dominant over short tails.
Both of these traits are inherited independently of each other. With respect to only these traits how many di erent
phenotypes would be present in a large population of mice?
A.
19.
B.
In squirrels, the gene for gray fur (G) is dominant over the gene for black fur (g). If 50% of a large litter of
squirrels are gray, the parental cross that produced this litter was most likely
A.
18.
Bb
The gene for tallness (T) is dominant over the gene for shortness (t) in pea plants. A homozygous dominant pea
plant is crossed with a heterozygous pea plant, and 200 seeds are produced. Approximately how many of these
seeds can be expected to produce plants that are homozygous dominant?
A.
17.
Bb
1
B.
2
C.
3
D. 4
Rabbits of a certain species produce yellow fat when on a diet of carrots and leafy vegetables. However, when
their diet does not include carrots and leafy vegetables, they develop white fat. Which is the best explanation for
these results?
A.
Colchicine can alter genotypes and phenotypes.
B.
C.
Polyploidy produces 2n gametes.
D. Environmental factors in uence gene expression.
page 4
Carrots cause mutations in rabbits.
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Genetics I
1.
Answer:
C
2.
Answer:
D
3.
Answer:
A
4.
Answer:
D
5.
Answer:
C
6.
Answer:
C
7.
Answer:
B
8.
Answer:
D
9.
Answer:
A
10.
Answer:
C
11.
Answer:
A
12.
Answer:
B
13.
Answer:
A
14.
Answer:
D
15.
Answer:
A
16.
Answer:
C
17.
Answer:
C
18.
Answer:
D
19.
Answer:
D
12/07/2012