Question 1

The most common fatal genetic disorder of Caucasians is
A)cholerA.
B)cystic fibrosis.
C)hemophilia.
D)sickle cell anemia.
E)muscular dystrophy.

Accepted Answer

Cystic fibrosis is the most common fatal genetic disorder of Caucasians, with a frequency of approximately 1 in every 2500 live births. It affects the lungs, pancreas, and other organs, leading to respiratory and digestive problems, and has no known cure. The other disorders listed (cholera, hemophilia, sickle cell anemia, and muscular dystrophy) are all genetic disorders, but they are not as common in Caucasians as cystic fibrosis.

Question 2

Traits that are carried on the X chromosome are said to be _________________.
A)autosomal
B)gametal
C)sex-linked
D)alleles

Accepted Answer

Traits that are carried on the X chromosome are called sex-linked traits because they are linked to the sex chromosomes. The Y chromosome is much smaller than the X chromosome and carries fewer genes, so traits carried on the X chromosome are more likely to be expressed in males. Examples of sex-linked traits include color blindness and hemophilia.

Question 3

A genetic _____ contains the distances between the gene loci measured in terms of the frequency of recombination.
A)map
B)profile
C)construct
D)clone

Accepted Answer

A genetic map is a diagram that shows the relative locations of genes or other DNA sequences on a chromosome. It is based on the frequency of recombination or crossover events between different genes, which reflects the physical distance between them. This information can be used to estimate the probability of genetic linkage between different traits or diseases, and to design experiments that test these relationships. Therefore, a genetic map contains the distances between gene loci measured in terms of recombination frequency, making it the best choice among the given options.

Question 4

If some alternative alleles with detrimental effects exist in significant proportions in populations,the condition is called
A)pleiotropy.
B)a syndrome.
C)epistasis.
D)a genetic disorder.
E)a genetic imbalancE.

Accepted Answer

The presence of alternative alleles with detrimental effects in significant proportions in a population is considered a genetic disorder. Genetic disorders are caused by mutations in genes or variations in the number or structure of chromosomes. These disorders can range from mild to severe and may be inherited or arise spontaneously.

Question 5

The white eye mutation in Drosophila was shown to be sex-linked and caused by a gene residing on chromosome
A)X.
B)Y.
C)1.
D)2.
E)autosomE.

Accepted Answer

The white eye mutation in Drosophila was shown to be sex-linked, meaning it is found on the sex chromosomes. In Drosophila, the female has two X chromosomes (XX) while the male has one X and one Y chromosome (XY). Therefore, the gene for white eye is found on the X chromosome and is sex-linked.

Question 6

Of the 23 pairs of human chromosomes,22 pairs are similar in the location of genes and are found in both males and females.These are called _________.
A)chromosomes
B)autosomes
C)alleles
D)gametes

Accepted Answer

Autosomes are the 22 pairs of chromosomes that are similar in males and females, and contain the majority of an individual's genes. Chromosomes (A) are the structures that carry genetic information. Alleles (C) are different forms of a gene. Gametes (D) are reproductive cells (sperm and egg) that contain half the number of chromosomes as a normal cell.

Question 7

One of the main reasons genes assort independently of one another is that
A)they produce unrelated traits.
B)they produce related traits.
C)they are on the same chromosome.
D)they are different alleles.
E)they are on different chromosomes.

Accepted Answer

Genes that are on different chromosomes assort independently of each other during meiosis. This means that the transmission of one gene to the offspring does not influence the transmission of another gene. Therefore, genes on different chromosomes produce unrelated traits, and their independent assortment is due to their physical location on different chromosomes.

Question 8

A fatal human disease in which the faulty gene codes for abnormal gland secretions leading to liver and lung failure is called ________________.
A)lung cancer
B)multiple sclerosis
C)muscular dystrophy
D)cystic fibrosis

Accepted Answer

The disease described is cystic fibrosis, a genetic disorder that affects the production of mucus, sweat, and digestive juices. The faulty gene leads to the production of thick, sticky mucus that clogs the lungs and pancreas, causing difficult breathing and digestive problems. Without treatment, the disease can lead to liver and lung failure, and it can be fatal.

Question 9

In sickle cell anemia,the defective hemoglobin differs from the normal hemoglobin by
A)the color of the pigment.
B)the size of the molecule.
C)a single amino acid substitution.
D)the total number of amino acids.
E)the type of blood cell it is found in.

Accepted Answer

Sickle cell anemia is caused by a point mutation in the beta-globin gene that leads to a single amino acid substitution in the hemoglobin protein. This substitution changes the shape of the hemoglobin molecule, causing it to form stiff rods that deform the shape of red blood cells, leading to their characteristic sickle shape.

Question 10

If a human female has two Barr bodies,it is almost certain that
A)her father had at least one Barr body.
B)her mother also had two Barr bodies.
C)she developed from a fertilized egg with 3 X chromosomes.
D)she is actually a male with female characteristics.
E)she is genetically a normal fertile femalE.

Accepted Answer

Barr bodies are inactive X chromosomes, and typically, only one X chromosome is activated in each cell of a female. Therefore, if a female has two Barr bodies, it means there are three X chromosomes present, and the female developed from a fertilized egg with 3 X chromosomes, a condition known as Triple X syndrome or Trisomy X. This condition is not always accompanied by physical or intellectual abnormalities, but there is an increased risk for developmental delays or learning disabilities, especially if there are additional chromosome abnormalities.

Question 11

The clotting of blood depends upon a chain of reactions that involve many different proteins;a faulty gene for any one of these proteins gives rise to the disease called __________.
A)hemophilia
B)HIV
C)multiple sclerosis
D)leukemia

Accepted Answer

Hemophilia is a disease that results from a faulty gene for one of the proteins involved in the clotting of blood. HIV is a virus that attacks the immune system, multiple sclerosis is a disease that affects the central nervous system, and leukemia is a cancer that affects the blood and bone marrow.

Question 12

Organisms generally have many more genes that assort independently than the number of chromosomes.This phenomenon is due to
A)independent assortment.
B)segregation.
C)crossing over.
D)epistasis.
E)pleiotropy.

Accepted Answer

Crossing over during meiosis allows for genes on the same chromosome to be recombined, leading to independent assortment of genes beyond the number of chromosomes.

Question 13

The geneticist who discovered the white eye mutation in Drosophila and helped establish that genes are carried on chromosomes was
A)Mendel.
B)Sutton.
C)Sturtevant.
D)Janssens.
E)Morgan.

Accepted Answer

The geneticist who discovered the white eye mutation in Drosophila and helped establish that genes are carried on chromosomes was Thomas Hunt Morgan.

Question 14

Genetic exchange between two arms of a chromosome pair is more likely to occur if the distance between the genes is great.It is called
A)epistasis.
B)pleiotropy.
C)crossing over.
D)allelic exchange.
E)mutation.

Accepted Answer

Crossing over is the process in which genetic material is exchanged between two homologous chromosomes during meiosis. This process is more likely to occur if the distance between the genes is great.

Question 15

In Drosophila,the sex of an individual is influenced by the number of copies of which chromosome?
A)autosome
B)X
C)1
D)2
E)white

Accepted Answer

In Drosophila, sex is determined by the ratio of X chromosomes to autosomes. Females have two X chromosomes and males have one X and one Y chromosome.

Question 16

Humans who have lost even one copy of an autosome are called
A)tetrasomics.
B)trisomics.
C)bisomics.
D)monosomics.
E)nullisomics.

Accepted Answer

Humans who have lost even one copy of an autosome are called monosomics. Mono means one, and in this case, it refers to the loss of one copy of a chromosome.

Question 17

Occasionally,chromosomes fail to separate during meiosis,leading to a condition in which the diploid number is not normal.This phenomenon is called
A)epistasis.
B)nondisjunction.
C)disjunction.
D)pleiotropy.
E)autosomy.

Accepted Answer

Nondisjunction occurs when chromosomes fail to separate during meiosis, resulting in an abnormal number of chromosomes in the daughter cells. This can lead to conditions such as Down syndrome, Turner syndrome, and Klinefelter syndrome. Epistasis, pleiotropy, and autosomy refer to other types of genetic phenomena and are not relevant to this question. Disjunction is a term used to describe the normal separation of chromosomes during meiosis, and is not applicable to this scenario.

Question 18

The most common condition of trisomy,in which three copies of a chromosome are present instead of the normal two,is of chromosome
A)X.
B)13.
C)15.
D)18.
E)21.

Accepted Answer

Trisomy 21, also known as Down syndrome, is the most common condition of trisomy in which an extra copy of chromosome 21 is present. Options A through D are incorrect as trisomies of these chromosomes are either incompatible with life or extremely rare.

Question 19

A human female with only one X chromosome is said to have a condition called
A)Alzheimer's disease.
B)hemophilia.
C)Turner syndrome.
D)Klinefelter syndrome.
E)Down syndromE.

Accepted Answer

Turner syndrome is a genetic disorder that affects females who have only one X chromosome or partial absence of the second X chromosome. It can lead to various health problems, such as short stature and infertility. Alzheimer's disease, hemophilia, Klinefelter syndrome, and Down syndrome are not related to having only one X chromosome.

Question 20

The theory of chromosomal inheritance was first proposed by
A)Mendel.
B)Morgan.
C)Knight.
D)Sutton.
E)Stern.

Accepted Answer

The theory of chromosomal inheritance was first proposed by Sutton in 1902.

Quiz 13: Chromosomes Mapping and the Meiosis - Inheritance Connection

The most common fatal genetic disorder of Caucasians is

Traits that are carried on the X chromosome are said to be _________________.

A genetic _____ contains the distances between the gene loci measured in terms of the frequency of recombination.

If some alternative alleles with detrimental effects exist in significant proportions in populations,the condition is called

The white eye mutation in Drosophila was shown to be sex-linked and caused by a gene residing on chromosome

Of the 23 pairs of human chromosomes,22 pairs are similar in the location of genes and are found in both males and females.These are called _________.

One of the main reasons genes assort independently of one another is that

A fatal human disease in which the faulty gene codes for abnormal gland secretions leading to liver and lung failure is called ________________.

In sickle cell anemia,the defective hemoglobin differs from the normal hemoglobin by

If a human female has two Barr bodies,it is almost certain that

The clotting of blood depends upon a chain of reactions that involve many different proteins;a faulty gene for any one of these proteins gives rise to the disease called __________.

Organisms generally have many more genes that assort independently than the number of chromosomes.This phenomenon is due to

The geneticist who discovered the white eye mutation in Drosophila and helped establish that genes are carried on chromosomes was

Genetic exchange between two arms of a chromosome pair is more likely to occur if the distance between the genes is great.It is called

In Drosophila,the sex of an individual is influenced by the number of copies of which chromosome?

Humans who have lost even one copy of an autosome are called

Occasionally,chromosomes fail to separate during meiosis,leading to a condition in which the diploid number is not normal.This phenomenon is called

The most common condition of trisomy,in which three copies of a chromosome are present instead of the normal two,is of chromosome

A human female with only one X chromosome is said to have a condition called

The theory of chromosomal inheritance was first proposed by