Download Practice test answers

Genes and Chromsomes
1 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
Name: practice test
Score: 0 / 19 (0%) [13 subjective questions not graded]
Genes and Chromsomes
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
1. Linked genes
a. are never separated.
b. assort independently.
c. are on the same chromosome.
d. are always recessive.
ANSWER: C
2. What is the probability that a human sperm cell will carry an X chromosome?
a. 0 percent
c. 50 percent
b. 25 percent
d. 100 percent
ANSWER: C
3. Colorblindness is more common in males than in females because
a. fathers pass the allele for colorblindness to their sons only.
b. the allele for colorblindness is located on the Y chromosome.
c. the allele for colorblindness is recessive and located on the X chromosome.
d. males who are colorblind have two copies of the allele for colorblindness.
ANSWER: C
4. Because the X chromosome contains genes that are vital for normal development, no baby has
been born
a. with one X chromosome.
c. without an X chromosome.
b. with three X chromosomes.
d. with four X chromosomes.
ANSWER: C
5. Which of the following combinations of sex chromosomes represents a female?
a. XY
c. XXXY
b. XXY
d. XX
ANSWER: D
6. In humans, a male has
a. one X chromosome only.
b. two X chromosomes.
3/26/2015 2:55 PM
Genes and Chromsomes
2 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
c. one X chromosome and one Y chromosome.
d. two Y chromosomes.
ANSWER: C
7. Human females produce egg cells that have
a. one X chromosome.
c. one X or one Y chromosome.
b. two X chromosomes.
d. one X and one Y chromosome.
ANSWER: A
8. Sex-linked genes are located on
a. the autosomes.
b. the X chromosome only.
c. the Y chromosome only.
d. both the X chromosome and Y chromosome.
ANSWER: D
9. Each gene occupies a specific place on a chromosome. This is referred to as the genes
a. genetic map
c. linkage
b. locus
d. neighborhood.
ANSWER: B
10. When genes are located on the same chromosome and when they tend to be inherited together
they are considered ___________.
a. a couple
c. independent
b. loci
d. linked
ANSWER: D
11. Morgan found that even when genes are linked there is a certain amount of recombination. This is
due to ______________
a. the law of independent assortment c. synapsis
b. the law of segregation
d. crossing over
ANSWER: D
12. A human sperm cell containing 24 chromosomes fertilizes a normal egg cell. There is now an
extra copy of chromosome number 21. The resulting zygote is now ______ for chromosome
number 21.
a. trisomic
c. polyploid
b. monosomic
d. diploid
ANSWER: A
3/26/2015 2:55 PM
Genes and Chromsomes
3 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
13. The genotype of a white-eyed male fruit fly is written. (Red eyes are dominant)
a. XYr
c. XrY
b. XRYr
d. YrYr
ANSWER: C
14. For most organisms the sex of their offspring is determined by the
a. male
c. neither
b. female
ANSWER: A
Matching
a. Duplication of part of a chromsome d. Base pair deletion
b. Nondisjunction
e. Inversion of part of a chromsome
c. Deletion of a part of a chromosomes
15. Addition or loss of a nucleotide pair
ANSWER: D
16. Homologous chromsomes are not seperated during meiosis
ANSWER: B
17. loss of a piece of a chromsome
ANSWER: C
18. A piece of a chromsome reattaches to a sister chromotid or a homologous chromosome
ANSWER: A
19. A piece of a chromsome reattaches to the original chromosome but in the reverse orientation
ANSWER: E
20. Part II
1. (Complete dominance) Cross a Heterozygous Tall, heterozygous wrinkled-seed pea
plant with a heterozygous tall, heterozygous wrinkled-seed pea plant. Tall is dominant to
short and wrinkled is dominant to smooth.
a. Parental Genotypes _____________________
3/26/2015 2:55 PM
Genes and Chromsomes
4 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
b. Punnett Square
c. Phenotypic ratio _______________________
2. (Complete dominance) Cross a person who is heterozygous for Huntington’s disease
with a person who is normal. Huntington’s disease is dominant, normal is recessive.
a. parental genotypes ______________________
b. punnett square
c. Genotypic ratio ______________________
d. Phenotypic ratio _____________________
3. (Incomplete dominance) Cross a pink snapdragon with a pink snapdragon. Red is
incompletely dominant to white.
a. parental genotypes ____________________
b. punnett square
c. Phenotypic ratio ________________________
d. Genotypic ratio ________________________
4. (Codominance) Cross a person who has sickle cell anemia with a person who is
heterozygous for sickle cell anemia. Sickle cell hemoglobin and normal hemoglobin are
both dominant.
a. Parental Genotypes __________________________
b. Punnett Square
c. Genotypic Ratio ____________________________
d. Phenotypic ratio ____________________________
5. (Sex-linked) Cross a Color blind male with a heterozygous normal female. Normal
vision is dominant. Color blind vision is recessive.
a. Parental Genotypes _____________________________
b. Punnett square
d. Phenotypic Ratio for the males _____________________________
3/26/2015 2:55 PM
Genes and Chromsomes
5 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
e. Phenotypic ratio for the females _____________________________
6. (Complete dominance / Codominance) Cross a person who is heterozygous for type A
blood with a person who has type O blood. Type A blood and Type B blood are both
dominant. Type O blood is recessive.
a. Parental Genotypes _____________________
b. Punnett Square
c. Genotypic Ratio _____________________
d. Phenotypic Ratio _____________________
RESPONSE:
ANSWER: This is the same worksheet we completed in class. Refer to the worksheet for the
answers
Short Answer
21. Color blindness is a recessive sex-linked genetic disorder. Cross a colorblind male with a
heterozygous (carrier) female.
a. parental genotypes
b. What is the phenotypic ratio for all of the offspring?
c. What percentage of the male offspring will be color blind?
d. What percentage of the female offspring will be colorblind?
e. punnett square
RESPONSE:
ANSWER: a. XbY, XBXb
b. 2:2 normal:colorblind
c. 50%
d. 50%
22. People who have the genetic disorder hemophilia are missing a protein for normal blood clotting.
This is a recessive sex-linked genetic disorder. A normal male is crossed with a normal female.
50% of the male offspring have hemophilia.
a. What are the parental genotypes?
3/26/2015 2:55 PM
Genes and Chromsomes
6 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
b. What is the phenotypic ratio for all of the offspring?
c. What percentage of the females has hemophilia?
d. Punnett square
RESPONSE:
ANSWER: a. XHXh, XHY
b. 3:1, normal:hemophilia
c. 0%
Other
USING SCIENCE SKILLS
Figure 14–2
23. Applying Concepts In the human karyotype in Figure 14-2, what are the chromosomes in each
numbered group called?
RESPONSE:
ANSWER: The chromosomes in each group are called homologous chromosomes.
24. Classifying Which chromosomes in Figure 14-2 are autosomes?
RESPONSE:
ANSWER: The chromosomes in groups 1 through 22 are autosomes.
25. Interpreting Graphics In the human karyotype in Figure 14-2, how many chromosomes are
shown?
RESPONSE:
ANSWER: Forty-seven chromosomes are shown.
26. Drawing Conclusions Identify the sex chromosomes in Figure 14-2. Does the karyotype show
the normal number of sex chromosomes? Explain.
3/26/2015 2:55 PM
Genes and Chromsomes
7 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
RESPONSE:
ANSWER: The karyotype shows two X chromosomes and one Y chromosome, which is not
normal. The normal number of sex chromosomes is two.
27. Inferring Is the individual represented by the karyotype in Figure 14-2 male or female? Explain.
RESPONSE:
ANSWER: The individual is male. In the presence of the Y chromosome, the human embryo
will also develop as a male, no matter how many X chromosomes are present.
USING SCIENCE SKILLS
To determine a person’s blood type, a drop of anti-A serum and a drop of anti-B serum are placed
at either end of a microscope slide. Then, a drop of the person’s blood is added to each drop of
serum. Clumping in anti-A serum or anti-B serum indicates the presence of antigen A or antigen
B in the blood, respectively.
Figure 14–3
28. Interpreting Graphics Which numbered slide in Figure 14–3 shows type B blood?
RESPONSE:
ANSWER: Slide 2 shows type B blood.
29. Inferring In Figure 14–3, which slide shows the blood of a person who can safely receive any
type of blood in a transfusion? Identify the person’s blood type.
RESPONSE:
ANSWER: Slide 3 shows the blood of a person who can safely receive any type of blood. The
person’s blood type is AB.
3/26/2015 2:55 PM
Genes and Chromsomes
8 of 8
http://www.cwcboe.org/cms/lib04/NJ01001185/Centricity/Domain/143/...
30. Interpreting Graphics Which slide in Figure 14–3 shows blood that contains no antigens? How
do you know?
RESPONSE:
ANSWER: The blood on slide 4 contains no antigens. There is no clumping in either drop of
blood.
31. Inferring In Figure 14–3, what is the genotype or genotypes of the person whose blood is shown
in slide 1?
RESPONSE:
ANSWER: The person’s genotype is IAIA or IAi.
32. Inferring Anti-sera are extracted from blood. Based on what is shown in Figure 14–3, what type
of blood does not contain anti-A or anti-B serum? Explain why.
RESPONSE:
ANSWER: Type AB blood does not contain anti-A or anti-B serum because it contains both
antigen A and antigen B. If it did contain either serum, the serum would cause the
blood to clump in the person’s body.
3/26/2015 2:55 PM