Deck 12: Chromosomes and Inheritance

Question 1

A woman who is a carrier for the hemophilia gene has a child with a man who does not have hemophilia. Which prediction is correct?

A) All of the sons and none of the daughters will have hemophilia.
B) All of the daughters and none of the sons will have hemophilia.
C) Half of the sons and half of the daughters will have hemophilia.
D) Half of the sons and none of the daughters will have hemophilia.
E) Half of the daughters and none of the sons will have hemophilia.

Answer 1

Half of the sons and none of the daughters will have hemophilia.

Question 2

Regarding the human sex chromosomes, which statement is correct?

A) The Y chromosome carries a greater number of genes for asexual traits than does the X chromosome.
B) X and Y are different in size but carry nearly equal numbers of genes.
C) The X chromosome carries more genes for asexual traits than does the Y.
D) The X chromosome carries only gender-related genes.
E) The X chromosome carries the genes for the development of male phenotype.

Answer 2

The X chromosome carries more genes for asexual traits than does the Y.

Question 3

On which human chromosome is the gene for opsin, the visual pigment located?

A) chromosome 7
B) X chromosome
C) chromosome 2
D) chromosome 16
E) Y chromosome

Answer 3

X chromosome

Question 4

Why do X-linked conditions appear more frequently in males than in females?

A) A male with a nonfunctioning allele on the X chromosome does not have another allele of that gene on the Y chromosome.
B) Males have no X chromosomes.
C) The Y chromosome carries many alleles that are recessive to alleles on the X.
D) Males are more likely to inherit an extra chromosome than females.
E) Females have no X chromosomes.

Question 5

What causes sickle-cell anemia?

A) complete lack of hemoglobin
B) a form of hemoglobin that is misshaped and thus distorts RBC
C) an extra X chromosome that results in production of too much hemoglobin
D) a defective hemoglobin that prevents the formation of blood clots
E) a single-celled parasite transmitted by a mosquito

Question 6

Which disease is autosomal and results in misshapen cells that clog capillaries?

A) malaria
B) sickle-cell anemia
C) hemophilia
D) Huntington disease
E) Turner syndrome

Question 7

If a disease is autosomal recessive like sickle-cell anemia, it is caused by:

A) failure to inherit one of the sex chromosomes.
B) failure to inherit one of the autosomes.
C) inheritance of an extra autosome.
D) a gene on a chromosome other than X or Y.
E) a gene on a chromosome other than an autosome.

Question 8

Much genetic information can be derived from pedigrees (family genetic histories). This is the primary method for obtaining genetic information for humans because:

A) humans cannot be crossed experimentally.
B) other animals have long life spans.
C) we know relatively little about human genetics.
D) humans have many chromosomes.

Question 9

What is one difference between polyploidy and aneuploidy?

A) Polyploidy is extra sets of chromosomes; aneuploidy does not increase by a full set.
B) Humans can be viable as polyploids but not as aneuploids.
C) Polyploidy is extra sex chromosomes; aneuploidy is extra autosomes.
D) Polyploidy is one extra chromosome; aneuploidy is one missing chromosome.
E) Polyploidy causes diseases and disorders in humans, aneuploidy does not.

Question 10

A nondisjunction event creates a human egg with one extra chromosome. If it is fertilized by a normal sperm, what is the total number of chromosomes in the zygote?

A) 47
B) 46
C) 45
D) 23
E) 22

Question 11

Refer to the figure above and then answer the question that follows.

-Nondisjunction in meiosis gives rise to gametes with abnormal chromosome numbers. Which of the events is likely to produce a higher percentage of abnormal gametes?

A) failure of homologous chromosomes to separate at meiosis I
B) failure of homologous chromosomes to separate at meiosis II
C) failure of sister chromatids to separate at meiosis I
D) failure of sister chromatids to separate at meiosis II
E) failure of sister chromatids to separate at mitosis

Question 12

Refer to the figure above and then answer the question that follows.

-What are the characteristics of the human sex chromosomes?

A) X chromosomes are larger in size.
B) Y chromosomes are smaller in size.
C) The X chromosome carries genes required by both males and females.
D) Y chromosomes carry genes required by males only.
E) All the above statements are true.

Question 13

Refer to the figure above and then answer the question that follows.

-A person with the genotype XO is mainly female, phenotypically. A person with the genotype XXY is mainly male. What can you conclude about the Y chromosome?

A) It has the same genes as X, just different alleles.
B) It has the same genes as X, in different orientation.
C) A Y chromosome confers maleness, regardless of the number of X chromosomes.
D) The only genes it carries are for female development.
E) A human cannot survive without a Y chromosome.

Question 14

A karyotype reveals that a woman is carrying a fetus that has 47 chromosomes. The test reveals that the genotype of the fetus is XXY. Which of the following statements is correct?

A) This is a trisomy.
B) This is Turner syndrome.
C) The fetus has Klinefelter syndrome, and most likely a nondisjunction event occurred in the mother during egg formation.
D) This is an autosomal trisomy.

Question 15

Which of the following chromosome combinations would NOT result in a viable zygote that could develop into an adult?

A) XX
B) XO (one X and no other sex chromosome)
C) YO (one Y and no other sex chromosome)
D) XY
E) XYY

Question 16

It has been well documented that women above 40 have an increasing chance of giving birth to babies with Down syndrome. Why is this so?

A) Egg development starts at the fetal stage of women.
B) Eggs are in meiosis I at that time of fertilization.
C) The egg doesn't complete division (meiosis II) until fertilization.
D) The cellular machinery is unable to separate the chromosomes and chromatids, resulting in gametes with abnormal chromosome numbers.
E) All the above are true.

Question 17

Which condition is caused by a chromosomal deletion?

A) Down syndrome
B) Huntington disease
C) Turner syndrome
D) cri-du-chat syndrome
E) sickle-cell anemia

Question 18

What is preimplantation genetic diagnosis (PGD)?

A) allows screening of embryos in mother's uterus after 14 weeks of pregnancy
B) allows screening of embryos before implantation in the uterus
C) allows screening of embryos in mother's uterus after 7 weeks of pregnancy
D) in vitro fertilization
E) genetic screening of parents

Question 19

What is the sequence of steps in preimplantation genetic diagnosis (PGD)? 1. formation of 8-celled embryo
2) induction of ovulation by hormones
3) removal of 8-12 mature eggs
4) fertilization by sperm in vitro
5) screening of a cell from the embryo by DNA testing

A) 1, 2, 3, 4, 5
B) 2, 3, 4, 1, 5
C) 3, 4, 5, 2, 1
D) 4, 3, 2, 1, 5
E) 5, 4, 3, 1, 2

Question 20

Why is Drosophila-the fruit fly-good experimental material in genetics?

A) It is small in size.
B) It has unusually large chromosomes.
C) It has a short generation time.
D) A and B are true.
E) A, B, and C are true.

Question 21

Thomas Hunt Morgan, working with fruit flies, discovered that male fruit flies could have the mutant trait of white eyes, even if they had only one "white allele. What was the significance of this finding?

A) It led to the discovery of aneuploidy.
B) It led to the discovery of polyploidy.
C) It led to the finding that only males have Y chromosomes.
D) It proved that crossing over occurs between the X and Y chromosomes.
E) It allowed him to assign the trait of eye color to the X chromosome.

Question 22

In a case of heterozygote advantage, it must be assumed that an allele has more than one effect on the phenotype of an organism.

Question 23

Plants that are polyploid either do not survive or, if they do, are sickly and weak.

Question 24

Phenylketonuria is an autosomal dominant disorder.

Question 25

The term for having one extra or one fewer chromosome than the standard diploid set is ________.

Question 26

A man and a woman are both carriers of sickle-cell anemia. The man is color blind. The woman is not color blind, nor is she a carrier of color blindness. Draw two Punnett squares, one showing inheritance of sickle-cell anemia, and the other showing inheritance of color blindness in this family.

Question 27

What was the significance of Thomas Hunt Morgan's observation that a male fruit fly could have white eyes with only one "white allele?

Question 28

What is prenatal testing?

Question 29

Now that we know the complete gene sequence (genome) of humans, will this knowledge make it more or less difficult for prospective parents who are concerned about inherited diseases and defects? Explain.