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Genetics. HW 1
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1.
Which genetic concept was proposed by Mendel?
6.
A.
chromosome nondisjunction
B.
independent assortment
A.
autosomes
B.
C.
multiple alleles
C.
heterozygotes
D. centrosomes
D. sex linkage
2.
7.
Two genes are linked if they are
A.
located on separate sex chromosomes
B.
members of an allelic pair
C.
located on the same chromosome
8.
D. able to segregate at random
3.
4.
Pairs of genes that control the same trait are
known as
A.
alleles
B.
C.
hybrids
D. loci
9.
gametes
Knowledge of the structure of DNA is important
in the study of life because DNA
A.
stores food
B.
transmits genetic information
C.
transmits chemical energy
10.
D. stores enzymes
5.
In humans there are 23 pairs of chromosomes.
One pair of the 23 are sex chromosomes. The
other 22 pairs are known as
Allelic pairs of genes are located only
A.
on homologous pairs of chromosomes
B.
in a DNA nucleotide
C.
in organisms that are homozygous
homozygotes
Within a cell, DNA is chie y found in the
A.
cell wall
B.
plasma membrane
C.
ribosomes
D. chromosomes
The individual strands of a double-stranded
chromosome are joined together by a
A.
cilium
B.
cyton
C.
chromatid
D. centromere
The basic principles of genetics were established
in the 19th century by
A.
Francis Crick
B.
Charles Darwin
C.
Jean Lamarck
D. Gregor Mendel
Mendel developed his basic principles of heredity
by
A.
microscopic study of chromosomes and genes
B.
breeding experiments with drosophila
C.
mathematical analysis of the o spring of pea
plants
D. ultracentrifugation studies of cell organelles
D. on nonhomologous chromosomes
page 1
11.
Traits that are controlled by genes found on an
X-chromosome are said to be
A.
autosomal dominant
B.
autosomal recessive
C.
codominant
16.
D. sex-linked
12.
13.
Homologous pairs of chromosomes are restored as
a result of
A.
gametogenesis
B.
C.
germination
D. di erentiation
17.
fertilization
only determined by dominant alleles
B.
determined by multiple alleles
C.
in uenced by environmental conditions
Meiotic cell division in animals is directly
responsible for the
A.
formation of gametes
Which statement best describes chromosomes that
contain genes for the same characteristics?
B.
fertilization of an egg
C.
growth of a cell
A.
They are present in a normal gamete.
D. production of muscle cells
B.
They are homologous.
C.
They occur in the same monoploid cell.
18.
Mendel developed the basic principles of heredity
by
A.
examining chromosomes with microscopes
B.
using X rays to induce mutations
C.
analyzing large numbers of o spring
19.
D. observing crossing-over during meiosis
15.
A.
D. a sex-linked trait
D. They are linked.
14.
A mother with type B blood and a father with
type A blood have four children, each with a
di erent blood type. The best explanation for the
occurrence of the four di erent blood types of the
children is that blood type is
Which molecule has the shape of a double-stranded
helix?
A.
RNA
B.
DNA
C.
ADP
D. ATP
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.
Tt
Tt
B.
Tt
tt
C.
TT
Tt
D. TT
tt
In a certain species of meadowmouse, dark coat
color is dominant over cream coat color. If
heterozygous dark-coated male mice are mated
with cream-coated female mice, what would be
the expected percentage of phenotypes in their
o spring?
A.
25% dark coated, 75% cream coated
B.
50% dark coated, 50% cream coated
C.
75% dark coated, 25% cream coated
D. 100% dark coated
page 2
Genetics. HW 1
20.
A trait which produces green pods is crossed with
a pea plant which produces yellow pods. The
resulting o spring had green pods. With respect
to pod color, the genotype of the o spring is most
likely
A.
heterozygous dominant
B.
pure recessive
C.
homozygous dominant
25.
26.
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.
Carrots cause mutations in rabbits.
C.
Polyploidy produces 2n gametes.
27.
In a species of corn, the diploid number of
chromosomes is 20. What is the number of
chromosomes found in each of the normal egg
cells produced by this species?
A.
23.
24.
5
B.
10
C.
20
A.
dominance
B.
C.
segregation
D. mutation
28.
linkage
In a fruit y in which the diploid number of
chromosomes is 8, the chromosome number in
each gamete is normally
16
B.
2
C.
B.
new gene combinations
C.
a chromosome number of 92
8
In cattle, black color is dominant over red color.
Which statement describes the o spring produced
when a homozygous black bull is mated with
several red cows?
A.
100% of the o spring will be red.
B.
100% of the o spring will be black.
C.
75% of the o spring will be black and 25%
will be red.
Synapsis and disjuntion are processes directly
involved in
A.
mitotic cell division
B.
meiotic cell division
C.
fertilization
D.
D. 40
Which basic genetic concept states that
chromosomes are distributed to gametes in a
random fashion?
A.
multiple alleles
D. 50% of the o spring will be black and 50%
will be red.
D. Environmental factors in uence gene
expression.
22.
A.
D. a polyploid condition
D. homozygous recessive
21.
Which is the result of normal meiosis and
fertilization in humans?
ssion
Normal mitosis results in the formation of two
nuclei that are genetically
A.
identical to each other and identical to the
original nucleus
B.
identical to each other but di erent from the
original nucleus
C.
di erent from each other but identical to the
original nucleus
D. di erent from each other and di erent from
the original nucleus
D. 4
page 3
Genetics. HW 1
29.
In guinea pigs, black coat color (B) is dominant
over white (b). Two black guinea pigs are mated.
Most of the o spring are black but some are
white.
33.
The cross described illustrates the principle of
30.
31.
32.
A.
dominance
B.
nondisjunction
C.
condominance
D. sex linkage
A human male will normally transmit the genes
on his X-chromosome to
A.
his sons, only
B.
his daughters, only
C.
all of his sons and daughters
D. half of his sons and half of his daughters
34.
Basic principles of heredity established by Mendel
include
Synapsis, crossing-over, and disjunction are events
that take place during the process of
A.
dominance, gene linkage, and sex linkage
A.
mitosis
B.
B.
dominance, independent assortment, and gene
linkage
C.
internal fertilization
D. binary ssion
C.
dominance, independent assortment, and
segregation
35.
meiosis
A diploid cell of a normal human male contains
D. independent assortment, gene linkage, and
segregation
A.
22 autosomes and two Y-chromosomes
B.
22 pairs of autosomes and two Y-chromosomes
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?
C.
22 pairs of autosomes, one X-chromosome,
and one Y-chromosome
A.
1:2:1
B.
C.
3:1
D. 1 : 3 : 1
D. 22 autosomes and two X-chromosomes
36.
9:7
A woman who is homozygous for type A blood
marries a man who is homozygous for type B
blood. All of their children have type AB blood.
This type of inheritance is known as codominance
because
The best method for determining if a woman may
be a carrier of the trait for color blindness is to
A.
some of the children would be expected to
have type O blood
A.
give her an eye examination
B.
B.
analyze a sample of her red blood cells
the allele for type A blood is dominant, and
the allele for type B blood is recessive
C.
analyze a sample of her urine
C.
the allele for type B blood is dominant, and
the allele for type A blood is recessive
D. the allele for type A blood and the allele
for type B blood are both expressed in the
children
D. check her family pedigree for the trait
page 4
Genetics. HW 1
37.
Heterozygous pink snapdragons are an example
of intermediate inheritance in plants. These
pink- owered plants may be produced as a result
of
39.
A.
a cross between parent plants whose ower
color is di erent from that of their o spring
A.
Intermediate inheritance involved alleles that
were not clearly dominant or recessive.
B.
the expression of a dominant gene
B.
Mutations occurred during gametogenesis.
C.
the expression of a recessive gene
C.
Crossing-over of white and red alleles
occurred during meiosis.
D. a cross between parent plants, both of which
have owers with red petals
38.
A cross between two plants that have pink owers
produced plants that have red, pink, or white
owers. Which is the most likely explanation for
these results?
D. Nondisjunction of homologous pairs of
chromosomes resulted in the production of
abnormal o spring.
The gene-chromosome theory states that
A.
chromosomes from both parents always have
identical genes
B.
genes exist at de nite loci in a linear sequence
on chromosomes
C.
homologous chromosomes do not have alleles
40.
D. Mendel's principles no longer apply to
genetics
page 5
Compared to the number of chromosomes
contained in a body cell of a parent, how many
chromosomes would normally be contained in a
gamete?
A.
the same number
B.
twice as many
C.
one-fourth as many
D. half as many
Genetics. HW 1