Question 1

Alleles are described as ______.

Accepted Answer

A)  homologous chromosomes 
B)  environmental factors that affect gene expression 
C)  alternate versions of a gene 
D)  alternate phenotypes 
A)  homologous chromosomes 
B)  environmental factors that affect gene expression 
C)  alternate versions of a gene 
D)  alternate phenotypes C

Question 2

An individual who is homozygous ______.

Accepted Answer

A)  expresses the dominant trait 
B)  carries two different alleles for a gene 
C)  carries two copies of the same allele for a gene 
D)  expresses the recessive trait 
A)  expresses the dominant trait 
B)  carries two different alleles for a gene 
C)  carries two copies of the same allele for a gene 
D)  expresses the recessive trait C

Question 3

Achondroplasia is a form of dwarfism caused by a dominant allele.The homozygous dominant genotype causes death,so individuals who have this condition are all heterozygotes.If a person with achondroplasia mates with a person who does not have achondroplasia,what percentage of their children would be expected to have achondroplasia?

Accepted Answer

A)  0% 
B)  50% 
C)  75% 
D)  100% 
A)  0% 
B)  50% 
C)  75% 
D)  100% B

Question 4

An individual with (naturally)curly hair and an individual with (naturally)straight hair mate; all of their offspring have (naturally)wavy hair. What is the relationship between the alleles for hair texture?

Accepted Answer

A)  pleiotropy 
B)  incomplete dominance 
C)  wavy hair is dominant to both straight and curly hair 
D)  codominance 
A)  pleiotropy 
B)  incomplete dominance 
C)  wavy hair is dominant to both straight and curly hair 
D)  codominance

Question 5

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds.The F1 plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F1 × F1 cross?

Accepted Answer

A)  1:2:1 
B)  2:1 
C)  3:1 
D)  9:3:3:1 
A)  1:2:1 
B)  2:1 
C)  3:1 
D)  9:3:3:1

Question 6

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

Accepted Answer

A)  2:1 
B)  1:1 
C)  1:2:1 
D)  3:1 
A)  2:1 
B)  1:1 
C)  1:2:1 
D)  3:1

Question 7

Please read the following scenario to answer the following question(s).
Widow's peak, a pointed hairline on the forehead, is a genetic trait caused by a dominant allele. It can be traced back through a family's history using pedigree analysis. The pedigree shown here shows three generations of a family. Notice that some individuals (shown in gray) have a widow's peak (W = dominant allele and w = recessive allele).
  
-Mary has the genotype ______.

Accepted Answer

A)  WW 
B)  ww 
C)  Ww 
D)  more information is needed. 
A)  WW 
B)  ww 
C)  Ww 
D)  more information is needed.

Question 8

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds.The seeds of all of the offspring are yellow.Why?

Accepted Answer

A)  The yellow allele is recessive to the green allele. 
B)  All of the offspring are homozygous yellow. 
C)  The yellow allele is dominant to the green allele. 
D)  The alleles are codominant. 
A)  The yellow allele is recessive to the green allele. 
B)  All of the offspring are homozygous yellow. 
C)  The yellow allele is dominant to the green allele. 
D)  The alleles are codominant.

Question 9

Round seeds (R)are dominant to wrinkled seeds (r),and yellow seeds (Y)are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual?

Accepted Answer

A)  1:2:1 
B)  9:3:3:1 
C)  3:1 
D)  1:1:1:1 
A)  1:2:1 
B)  9:3:3:1 
C)  3:1 
D)  1:1:1:1

Question 10

Which of the following techniques is used to collect fetal cells during pregnancy for genetic testing?

Accepted Answer

A)  testcross 
B)  dihybrid cross 
C)  amniocentesis 
D)  pedigree analysis 
A)  testcross 
B)  dihybrid cross 
C)  amniocentesis 
D)  pedigree analysis

Question 11

To determine the phenotype of an individual who expresses a dominant trait,you would cross that individual with an individual who ______.

Accepted Answer

A)  expresses the dominant trait 
B)  is homozygous recessive for that trait 
C)  is homozygous dominant for that trait 
D)  is heterozygous for that trait 
A)  expresses the dominant trait 
B)  is homozygous recessive for that trait 
C)  is homozygous dominant for that trait 
D)  is heterozygous for that trait

Question 12

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants,and all of the resulting offspring produced purple flowers.The offspring are all ______,and the allele for purple flowers is ______.

Accepted Answer

A)  heterozygotes... recessive 
B)  heterozygotes... dominant 
C)  homozygotes... recessive 
D)  homozygotes... dominant 
A)  heterozygotes... recessive 
B)  heterozygotes... dominant 
C)  homozygotes... recessive 
D)  homozygotes... dominant

Question 13

Attached earlobes are recessive to free earlobes. What is the probability of having a child with attached earlobes when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

Accepted Answer

A)  0% 
B)  25% 
C)  50% 
D)  75% 
A)  0% 
B)  25% 
C)  50% 
D)  75%

Question 14

According to Mendel's law of segregation,______.

Accepted Answer

A)  two alleles segregate into each gamete 
B)  more gametes carrying the dominant allele are produced than gametes carrying the recessive allele 
C)  gametes have one copy of each allele 
D)  gametes are diploid 
A)  two alleles segregate into each gamete 
B)  more gametes carrying the dominant allele are produced than gametes carrying the recessive allele 
C)  gametes have one copy of each allele 
D)  gametes are diploid

Question 15

The ______ is most commonly found in nature.

Accepted Answer

A)  recessive trait 
B)  wild-type trait 
C)  parental 
D)  dominant trait 
A)  recessive trait 
B)  wild-type trait 
C)  parental 
D)  dominant trait

Question 16

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed,and have both cardiovascular and eye defects. The inheritance of Marfan syndrome is an example of ______.

Accepted Answer

A)  codominance 
B)  a recessive disorder 
C)  pleiotropy 
D)  incomplete dominance 
A)  codominance 
B)  a recessive disorder 
C)  pleiotropy 
D)  incomplete dominance

Question 17

Please refer to the following art to answer the following question(s).
  
-In the accompanying art you see a table with the actual number of offspring that resulted from a dihybrid cross.The numbers do not show the 9:3:3:1 ratio predicted.One phenotype occurred more than predicted; another occurred less.The reason could be because ______.

Accepted Answer

A)  of errors in mitosis 
B)  some of the alleles were linked 
C)  some of the alleles were sex-linked 
D)  of polygenic inheritance 
A)  of errors in mitosis 
B)  some of the alleles were linked 
C)  some of the alleles were sex-linked 
D)  of polygenic inheritance

Question 18

What is the basis of Mendel's laws?

Accepted Answer

A)  the behavior of chromosomes during prophase I of meiosis only 
B)  the behavior of chromosomes during mitotic anaphase 
C)  the behavior of chromosomes during prophase I and prophase II of meiosis 
D)  the behavior of chromosomes during metaphase I and anaphase I of meiosis 
A)  the behavior of chromosomes during prophase I of meiosis only 
B)  the behavior of chromosomes during mitotic anaphase 
C)  the behavior of chromosomes during prophase I and prophase II of meiosis 
D)  the behavior of chromosomes during metaphase I and anaphase I of meiosis

Question 19

What is the key to the recognition of incomplete dominance?

Accepted Answer

A)  The phenotype of the heterozygote falls between the phenotypes of the homozygotes. 
B)  The trait exhibits a continuous distribution. 
C)  The alleles affect more than one trait. 
D)  The heterozygote expresses the phenotype of both homozygotes. 
A)  The phenotype of the heterozygote falls between the phenotypes of the homozygotes. 
B)  The trait exhibits a continuous distribution. 
C)  The alleles affect more than one trait. 
D)  The heterozygote expresses the phenotype of both homozygotes.

Question 20

Which of these crosses will only produce heterozygous offspring?

Accepted Answer

A)  AA × aa 
B)  AA × Aa 
C)  Aa × Aa 
D)  Aa × aa 
A)  AA × aa 
B)  AA × Aa 
C)  Aa × Aa 
D)  Aa × aa

Exam 9: Patterns of Inheritance

Alleles are described as ______.

An individual who is homozygous ______.

An individual with (naturally)curly hair and an individual with (naturally)straight hair mate; all of their offspring have (naturally)wavy hair. What is the relationship between the alleles for hair texture?

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds.The F1 plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F1 × F1 cross?

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds.The seeds of all of the offspring are yellow.Why?

Round seeds (R)are dominant to wrinkled seeds (r),and yellow seeds (Y)are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual?

Which of the following techniques is used to collect fetal cells during pregnancy for genetic testing?

To determine the phenotype of an individual who expresses a dominant trait,you would cross that individual with an individual who ______.

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants,and all of the resulting offspring produced purple flowers.The offspring are all ______,and the allele for purple flowers is ______.

Attached earlobes are recessive to free earlobes. What is the probability of having a child with attached earlobes when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

According to Mendel's law of segregation,______.

The ______ is most commonly found in nature.

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed,and have both cardiovascular and eye defects. The inheritance of Marfan syndrome is an example of ______.

What is the basis of Mendel's laws?

What is the key to the recognition of incomplete dominance?

Which of these crosses will only produce heterozygous offspring?

Introduction- Biology Today

Essential Chemistry for Biology

The Molecules of Life

A Tour of the Cell

The Working Cell

Cellular Respiration: Obtaining Energy from Food

Photosynthesis: Using Light to Make Food

Cellular Reproduction: Cells from Cells

The Structure and Function of DNA

How Genes Are Controlled

DNA Technology

How Populations Evolve

How Biological Diversity Evolves

The Evolution of Microbial Life

Plants, Fungi, and the Move onto Land

The Evolution of Animals

An Introduction to Ecology and the Biosphere

Population Ecology

Communities and Ecosystems

Unifying Concepts of Animal Structure and Function

Nutrition and Digestion

Circulation and Respiration

The Body's Defenses

Hormones

Reproduction and Development

Nervous, Sensory, and Locomotor Systems

The Life of a Flowering Plant

The Working Plant

Filters

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds.The F₁ plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F₁ × F₁ cross?

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants,and all of the resulting offspring produced purple flowers.The offspring are all ,and the allele for purple flowers is .