Question 1

An autosomal recessive disorder:

Accepted Answer

A)  requires that only one parent be a carrier. 
B)  displays its symptoms only in heterozygotes. 
C)  is more frequent in males than females. 
D)  will appear only in children of parents who both carry the gene. 
E)  is dominant in females. 
A)  requires that only one parent be a carrier. 
B)  displays its symptoms only in heterozygotes. 
C)  is more frequent in males than females. 
D)  will appear only in children of parents who both carry the gene. 
E)  is dominant in females.

Question 2

Explain why a female can be heterozygous for an X-linked gene but a male cannot.

Accepted Answer

Females have two X chromosomes and two a

Question 3

Nondisjunction of the X chromosomes may occur during formation of gametes and produce two kinds of eggs. If normal sperm fertilizes these two kinds of eggs, which of the following pairs of genotypes are possible?

Accepted Answer

A)  XX and XY 
B)  XXY and XO 
C)  XYY and XO 
D)  XYY and YO 
A)  XX and XY 
B)  XXY and XO 
C)  XYY and XO 
D)  XYY and YO

Question 4

What is nondisjunction?

Accepted Answer

A)  failure of sperm and egg to fuse in fertilization 
B)  failure of cells to divide by cytokinesis in meiosis 
C)  failure of chromosomes to duplicate before mitosis or meiosis 
D)  failure of homologous chromosomes or sister chromatids to separate in meiosis 
E)  an extra duplication of the chromosomes before mitosis or meiosis 
A)  failure of sperm and egg to fuse in fertilization 
B)  failure of cells to divide by cytokinesis in meiosis 
C)  failure of chromosomes to duplicate before mitosis or meiosis 
D)  failure of homologous chromosomes or sister chromatids to separate in meiosis 
E)  an extra duplication of the chromosomes before mitosis or meiosis

Question 5

Color blindness is caused by an X-linked recessive gene. A color-blind man and a woman with normal vision whose father was color blind have a son. The probability that their son is color blind is:

Accepted Answer

A)  0.25 (or 25 percent). 
B)  0.50 (or 50 percent). 
C)  0.75 (or 75 percent). 
D)  1.00 (or 100 percent). 
E)  none of these. 
A)  0.25 (or 25 percent). 
B)  0.50 (or 50 percent). 
C)  0.75 (or 75 percent). 
D)  1.00 (or 100 percent). 
E)  none of these.

Question 6

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

Accepted Answer

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

Question 7

A person with only one allele for a recessive condition who does not have the condition is called a ________.

Accepted Answer

The answer of A person with only one allele for...

Question 8

What is one difference between polyploidy and aneuploidy?

Accepted Answer

A)  Polyploidy is extra sets of chromosomes; aneuploidy occurs when there are either more or fewer chromosomes than normally exist in its species 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. 
A)  Polyploidy is extra sets of chromosomes; aneuploidy occurs when there are either more or fewer chromosomes than normally exist in its species 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 9

Match the following.
A) aneuploidy
B) nondisjunction
C) duplication
D) translocation
E) deletion
-Only 1 percent of human embryos with this condition survive.

Accepted Answer

The answer of Match the following.
A) aneuploidy
B) nondisjunction
C) duplication
D) translocation
E)...

Question 10

The state of having more than two sets of chromosomes is called:

Accepted Answer

A)  autosomal. 
B)  dominant. 
C)  polyploidy. 
D)  aneuploidy. 
E)  nondisjunction. 
A)  autosomal. 
B)  dominant. 
C)  polyploidy. 
D)  aneuploidy. 
E)  nondisjunction.

Question 11

If a zygote has the genotype XYY, how many total chromosomes were in the sperm before it fused with the egg?

Accepted Answer

A)  20 
B)  21 
C)  22 
D)  23 
E)  24 
A)  20 
B)  21 
C)  22 
D)  23 
E)  24

Question 12

A single nondisjunction event results in some gametes with more chromosomes and some gametes with fewer chromosomes.

Accepted Answer

A) True 
 B)False

Question 13

Polyploidy is better tolerated in plants than in animals.

Accepted Answer

A) True 
 B)False

Question 14

Aneuploid human embryos are least likely to survive except those involving:

Accepted Answer

A)  chromosome 1, 2, 3, X, Y. 
B)  chromosome 1, 2, 3, 4, 5. 
C)  chromosome 13, 18, 21, X, Y. 
D)  chromosome 6, 7, 8, 9, 10. 
E)  chromosome 11, 12, 14, 15. 
A)  chromosome 1, 2, 3, X, Y. 
B)  chromosome 1, 2, 3, 4, 5. 
C)  chromosome 13, 18, 21, X, Y. 
D)  chromosome 6, 7, 8, 9, 10. 
E)  chromosome 11, 12, 14, 15.

Question 15

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?

Accepted Answer

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

Question 16

A person who is heterozygous for the Huntington disease (HD) allele has offspring with someone who does not have HD. What proportion of their children will have HD?

Accepted Answer

A)  1/16 
B)  1/10 
C)  1/8 
D)  1/4 
E)  1/2 
A)  1/16 
B)  1/10 
C)  1/8 
D)  1/4 
E)  1/2

Question 17

In a pedigree chart, a darkened square demonstrates a:

Accepted Answer

A)  diseased male. 
B)  diseased female. 
C)  normal male. 
D)  normal female. 
A)  diseased male. 
B)  diseased female. 
C)  normal male. 
D)  normal female.

Question 18

Down syndrome in humans is caused by:

Accepted Answer

A)  an extra X chromosome. 
B)  an extra y chromosome. 
C)  three copies of chromosome 21. 
D)  three copies of chromosome 13. 
E)  a single copy of chromosome 21. 
A)  an extra X chromosome. 
B)  an extra y chromosome. 
C)  three copies of chromosome 21. 
D)  three copies of chromosome 13. 
E)  a single copy of chromosome 21.

Question 19

Phenylketonuria is the most commonly inherited genetic disorder that affects nervous system development. It occurs in 1 out of every 10,000 births in the United States and Europe. How would you design a study to determine if phenylketonuria is an autosomal dominant or autosomal recessive disorder? How would you be able to determine if it is dominant or recessive?

Accepted Answer

The study would analyze the inheritance

Question 20

A woman who does not carry the color-blindness allele has children with a man who is color blind. What proportion of their children will be color blind?

Accepted Answer

A)  all 
B)  1/4 
C)  1/2 
D)  3/4 
E)  none 
A)  all 
B)  1/4 
C)  1/2 
D)  3/4 
E)  none

Exam 12: Units of Heredity: Chromosomes and Inheritance

An autosomal recessive disorder:

Explain why a female can be heterozygous for an X-linked gene but a male cannot.

Nondisjunction of the X chromosomes may occur during formation of gametes and produce two kinds of eggs. If normal sperm fertilizes these two kinds of eggs, which of the following pairs of genotypes are possible?

What is nondisjunction?

Color blindness is caused by an X-linked recessive gene. A color-blind man and a woman with normal vision whose father was color blind have a son. The probability that their son is color blind is:

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

A person with only one allele for a recessive condition who does not have the condition is called a ________.

What is one difference between polyploidy and aneuploidy?

Match the following. A) aneuploidy B) nondisjunction C) duplication D) translocation E) deletion -Only 1 percent of human embryos with this condition survive.

The state of having more than two sets of chromosomes is called:

If a zygote has the genotype XYY, how many total chromosomes were in the sperm before it fused with the egg?

A single nondisjunction event results in some gametes with more chromosomes and some gametes with fewer chromosomes.

Polyploidy is better tolerated in plants than in animals.

Aneuploid human embryos are least likely to survive except those involving:

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 person who is heterozygous for the Huntington disease (HD) allele has offspring with someone who does not have HD. What proportion of their children will have HD?

In a pedigree chart, a darkened square demonstrates a:

Down syndrome in humans is caused by:

A woman who does not carry the color-blindness allele has children with a man who is color blind. What proportion of their children will be color blind?

Science As a Way of Learning: a Guide to the Natural World

Fundamental Building Blocks: Chemistry, Water, and Ph

Lifes Components: Biological Molecules

Lifes Home: the Cell

Lifes Border: the Plasma Membrane

Lifes Mainspring: an Introduction to Energy

Vital Harvest: Deriving Energy From Food

The Green Worlds Gift: Photosynthesis

The Links in Lifes Chain: Genetics and Cell Division

Preparing for Sexual Reproduction: Meiosis

The First Geneticist: Mendel and His Discoveries

Passing on Lifes Information: Dna Structure and Replication

How Proteins Are Made: Genetic Transcription, Translation, and Regulation

The Future Isnt What It Used to Be: Biotechnology

An Introduction to Evolution: Charles Darwin, Evolutionary Thought, and the Evidence for Evolution

The Means of Evolution: Microevolution

The Outcomes of Evolution: Macroevolution

A Slow Unfolding: the History of Life on Earth

Arriving Late, Traveling Far: the Evolution of Human Beings

Viruses, Bacteria, Archaea, and Protists: the Diversity of Life 1

Fungi : the Diversity of Life 2

Animals: the Diversity of Life 3

Plants: the Diversity of Life 4

The Angiosperms: Form and Function in Flowering Plants

Body Support and Movement: the Integumentary, Skeletal, and Muscular Systems

Communication and Control 1: the Nervous System

Communication and Control 2: the Endocrine System

Defending the Body: the Immune System

Transport and Exchange 1: Blood and Breath

Transport and Exchange 2: Digestion, Nutrition, and Elimination

An Amazingly Detailed Script: Animal Development

How the Baby Came to Be: Human Reproduction

An Interactive Living World 1: Populations in Ecology

An Interactive Living World 2: Communities in Ecology

An Interactive Living World 3: Ecosystems and Biomes

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