Question 1

A couple has two female children.What is the probability that their next child will be male?

Accepted Answer

A)  25% 
B)  50% 
C)  33% 
D)  67% 
A)  25% 
B)  50% 
C)  33% 
D)  67%

Question 2

Red-green color blindness is inherited as a sex-linked recessive trait.The gene is found on the X chromosome.How can a man with normal color vision father a daughter who is red-green color-blind?

Accepted Answer

A)  The woman with whom he mates is red-green color-blind. 
B)  The man is heterozygous for red-green color blindness. 
C)  He can't (unless there is a mutation). 
D)  The man's mother carries an allele for red-green color blindness, and the expression of the trait skipped a generation. 
A)  The woman with whom he mates is red-green color-blind. 
B)  The man is heterozygous for red-green color blindness. 
C)  He can't (unless there is a mutation). 
D)  The man's mother carries an allele for red-green color blindness, and the expression of the trait skipped a generation.

Question 3

Please read the following scenario to answer the following question.
The parents of a child with unusual disease symptoms take the child to a doctor for help. The doctor suspects that the condition might have a genetic basis. She recommends that the child be taken to a specialty clinic where physicians and staff members are trained to diagnose genetic diseases and counsel parents. Ultimately, the child is diagnosed with a rare recessively inherited disease. The parents are tested for the gene, and both are found to be heterozygous. The parents want to have another child but are afraid this child will also be affected.
-What would genetic counselors say is the probability that the second child will have the disease?

Accepted Answer

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

Question 4

Many human traits,such as our performance on intelligence tests or our susceptibility to heart disease,are ______.

Accepted Answer

A)  determined only by our genes 
B)  influenced by both genes and the environment 
C)  determined by genes in some people and by the environment in other people 
D)  not affected by our genes 
A)  determined only by our genes 
B)  influenced by both genes and the environment 
C)  determined by genes in some people and by the environment in other people 
D)  not affected by our genes

Question 5

Please refer to the following art to answer the following question(s).
  
-Recombinant offspring were produced by the mating shown in the accompanying art.What is the recombination frequency of purple round and red long offspring?

Accepted Answer

A)  21% 
B)  381 
C)  21 + 21 
D)  11% 
A)  21% 
B)  381 
C)  21 + 21 
D)  11%

Question 6

An individual with the blood group genotype LMLN has the phenotype MN. What is the relationship between the LM and LN alleles?

Accepted Answer

A)  codominance 
B)  pleiotropy 
C)  LN is dominant 
D)  incomplete dominance 
A)  codominance 
B)  pleiotropy 
C)  LN is dominant 
D)  incomplete dominance

Question 7

The recombination frequency between gene B and gene C is 11%. The recombination frequency between gene B and gene D is 5%. The recombination frequency between gene C and gene D is 15%. What would be the arrangement of these genes on a linkage map?

Accepted Answer

A)  CDB 
B)  DBC 
C)  BCD 
D)  More information is needed. 
A)  CDB 
B)  DBC 
C)  BCD 
D)  More information is needed.

Question 8

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce a(n)______.

Accepted Answer

A)  purebred variety 
B)  hybrid 
C)  P generation 
D)  F2 generation 
A)  purebred variety 
B)  hybrid 
C)  P generation 
D)  F2 generation

Question 9

Hypophosphatemia (vitamin D-resistant rickets)is inherited as an sex-linked dominant trait.The relevant gene is found on the X chromosome.What is the expected outcome of a cross between a homozygous recessive woman and a man with hypophosphatemia?

Accepted Answer

A)  All of their daughters and none of their sons exhibit hypophosphatemia. 
B)  Fifty percent of their daughters and fifty percent of their sons exhibit hypophosphatemia. 
C)  All of their sons and none of their daughters exhibit hypophosphatemia. 
D)  Twenty-five percent of their offspring exhibit hypophosphatemia. 
A)  All of their daughters and none of their sons exhibit hypophosphatemia. 
B)  Fifty percent of their daughters and fifty percent of their sons exhibit hypophosphatemia. 
C)  All of their sons and none of their daughters exhibit hypophosphatemia. 
D)  Twenty-five percent of their offspring exhibit hypophosphatemia.

Question 10

The best definition of a purebred plant is one that ______.

Accepted Answer

A)  cannot be cross-fertilized 
B)  self-fertilizes to produce offspring identical to the parent 
C)  produces sterile offspring when cross-fertilized 
D)  self-fertilizes to produce hybrid offspring 
A)  cannot be cross-fertilized 
B)  self-fertilizes to produce offspring identical to the parent 
C)  produces sterile offspring when cross-fertilized 
D)  self-fertilizes to produce hybrid offspring

Question 11

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).
  
-Janice's genotype is _______.

Accepted Answer

A)  Ww 
B)  WW 
C)  ww 
D)  WW or Ww 
A)  Ww 
B)  WW 
C)  ww 
D)  WW or Ww

Question 12

In humans,the presence or absence of dimples is a trait controlled by a single gene.What is the genotype of an individual who is heterozygous for dimples?

Accepted Answer

A)  DD 
B)  Dd 
C)  dd 
D)  DI 
A)  DD 
B)  Dd 
C)  dd 
D)  DI

Question 13

In humans,the inheritance of ______ is best explained as being polygenic.

Accepted Answer

A)  cystic fibrosis 
B)  height 
C)  blood type 
D)  sickle-cell disease 
A)  cystic fibrosis 
B)  height 
C)  blood type 
D)  sickle-cell disease

Question 14

What is the best explanation for a BbCc × bbcc cross producing offspring in a 5:5:1:1 phenotypic ratio?

Accepted Answer

A)  linked genes 
B)  polygenic inheritance 
C)  incomplete dominance 
D)  codominance 
A)  linked genes 
B)  polygenic inheritance 
C)  incomplete dominance 
D)  codominance

Question 15

A dihybrid cross produces 30 recombinant offspring out of a total of 1,000 offspring.What is the recombination frequency of the two gene pairs?

Accepted Answer

A)  6% 
B)  3% 
C)  30% 
D)  1.5% 
A)  6% 
B)  3% 
C)  30% 
D)  1.5%

Question 16

An individual heterozygous for cystic fibrosis ______.

Accepted Answer

A)  cannot have children with cystic fibrosis 
B)  is a carrier 
C)  will have children who are all carriers of cystic fibrosis 
D)  has cystic fibrosis 
A)  cannot have children with cystic fibrosis 
B)  is a carrier 
C)  will have children who are all carriers of cystic fibrosis 
D)  has cystic fibrosis

Question 17

What is the key to the recognition of a trait whose expression is determined by the effects of two or more genes (polygenic inheritance)?

Accepted Answer

A)  A mating between a homozygous and a heterozygous individual produces more than the expected number of offspring expressing the dominant trait. 
B)  All of the alleles of the gene for that trait are equally expressed. 
C)  Pleiotropy occurs. 
D)  The trait varies along a continuum in the population. 
A)  A mating between a homozygous and a heterozygous individual produces more than the expected number of offspring expressing the dominant trait. 
B)  All of the alleles of the gene for that trait are equally expressed. 
C)  Pleiotropy occurs. 
D)  The trait varies along a continuum in the population.

Question 18

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).
  
-This pedigree supports the fact that widow's peak is due to a dominant allele,because if it were due to a recessive allele and both parents show the recessive phenotype,then ______.

Accepted Answer

A)  none of the sons would have a widow's peak 
B)  all of the offspring would have a widow's peak 
C)  none of the daughters would have a widow's peak 
D)  all of the daughters and none of the sons would have a widow's peak 
A)  none of the sons would have a widow's peak 
B)  all of the offspring would have a widow's peak 
C)  none of the daughters would have a widow's peak 
D)  all of the daughters and none of the sons would have a widow's peak

Question 19

What is the key to the recognition of codominance?

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

Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome.A man with three nostrils has a daughter who has a son with a man who has only two nostrils.What is the probability that the three-nostriled man's grandson has three nostrils?

Accepted Answer

A)  0% 
B)  25% 
C)  50% 
D)  100% 
A)  0% 
B)  25% 
C)  50% 
D)  100%

Exam 9: Patterns of Inheritance

A couple has two female children.What is the probability that their next child will be male?

Red-green color blindness is inherited as a sex-linked recessive trait.The gene is found on the X chromosome.How can a man with normal color vision father a daughter who is red-green color-blind?

Many human traits,such as our performance on intelligence tests or our susceptibility to heart disease,are ______.

Please refer to the following art to answer the following question(s). -Recombinant offspring were produced by the mating shown in the accompanying art.What is the recombination frequency of purple round and red long offspring?

An individual with the blood group genotype LMLN has the phenotype MN. What is the relationship between the LM and LN alleles?

The recombination frequency between gene B and gene C is 11%. The recombination frequency between gene B and gene D is 5%. The recombination frequency between gene C and gene D is 15%. What would be the arrangement of these genes on a linkage map?

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce a(n)______.

Hypophosphatemia (vitamin D-resistant rickets)is inherited as an sex-linked dominant trait.The relevant gene is found on the X chromosome.What is the expected outcome of a cross between a homozygous recessive woman and a man with hypophosphatemia?

The best definition of a purebred plant is one that ______.

In humans,the presence or absence of dimples is a trait controlled by a single gene.What is the genotype of an individual who is heterozygous for dimples?

In humans,the inheritance of ______ is best explained as being polygenic.

What is the best explanation for a BbCc × bbcc cross producing offspring in a 5:5:1:1 phenotypic ratio?

A dihybrid cross produces 30 recombinant offspring out of a total of 1,000 offspring.What is the recombination frequency of the two gene pairs?

An individual heterozygous for cystic fibrosis ______.

What is the key to the recognition of a trait whose expression is determined by the effects of two or more genes (polygenic inheritance)?

What is the key to the recognition of codominance?

Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome.A man with three nostrils has a daughter who has a son with a man who has only two nostrils.What is the probability that the three-nostriled man's grandson has three nostrils?

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

An individual with the blood group genotype L^MLN has the phenotype MN. What is the relationship between the L^M and L^N alleles?