Biology Chapter 9

Which of the following is true concerning sex-linked disorders? To be affected, daughters must inherit it from both parents. To be affected, sons must inherit it from both parents. Females will show the disorder if they inherit if from one parent. If mom has the disorder, her sons will not have it.

To be affected, daughters must inherit it from both parents.

Which of the following statements is true concerning inheritance of autosomal recessive disorders? Most affected children will have an affected parent. Heterozygotes are affected. Two affected parents will always have affected children. Sex chromosomes are involved.

Two affected parents will always have affected children.

Klinefelter's syndrome is represented by the genotype XO XXX XXY XYY

XXY

A monohybrid cross is a breeding experiment in which the parental varieties differ in only two traits. a breeding experiment in which the parental varieties differ in only one trait. a breeding experiment in which the parental varieties have many traits. a breeding experiment in which the parental varieties differ in three traits.

a breeding experiment in which the parental varieties differ in only one trait.

If mom is a carrier of baldness and dad is bald, what is the probability that one of their sons will be bald? Baldness is an x-linked disorder. 25% 50% 75% 100%

50%

Both a man and a woman are heterozygous for freckles. Freckles (F) are dominant over no freckles (f). What is the chance that their child will have freckles? 25% 75% 100% 15%

75%

Which of the following statements regarding genotypes and phenotypes is false? The genetic makeup of an organism constitutes its genotype. The expressed physical traits of an organism are called its phenotype. An organism with two different alleles for a single trait is said to be homozygous for that trait. Alleles are alternate forms of a gene.

An organism with two different alleles for a single trait is said to be homozygous for that trait.

For the following blood types, determine which parents baby 1 belongs to:Baby 1 has type B bloodPossible parents:Mr. Doe has type AMrs. Doe has type AMr. Jones has type ABMrs. Jones has type A Baby 1 belongs to the Doe family Baby 1 belongs to the Jones Family

Baby 1 belongs to the Jones Family

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes? dd and dd Dd and DD Dd and Dd DD and dd

Dd and Dd

Which of the following statements regarding Down syndrome is false? Down syndrome is least likely to be seen in the infants of mothers over 40. Trisomy 21 is the cause of Down syndrome. People with Down syndrome usually have a shorter life span than normal. Down syndrome is the most common serious birth defect in the United States.

Down syndrome is least likely to be seen in the infants of mothers over 40.

Who is called the Father of Genetics? Einstein James Watson Francis Crick Gregor Mendel

Gregor Mendel

Which of the following statements is true concerning inheritance of autosomal dominant disorders? Affected children will not have an affected parent. Heterozygotes are affected. Two unaffected parents will have an affected child. Sex chromosomes are involved.

Heterozygotes are affected.

Which of the following is an autosomal dominant disorder? Sickle cell disease Cystic fibrosis Tay Sachs Huntington disease

Huntington disease

Which of the following is an example of incomplete dominance in humans? Sickle- cell anemia ABO blood groups Skin color Hypercholesterolemia

Hypercholesterolemia

Which of the following traits are examples of polygenic inheritance? skin color behavior height all of these.

all of these.

A mutation in the BRCA gene causes colon cancer. prostate cancer. skin cancer. breast cancer.

breast cancer.

A person with AB blood illustrates the principle of pleiotropy. incomplete dominance. codominance. polygenic inheritance.

codominance.

According to this figure, heterozygotes for this form of hypercholesterolemia suffer from the disease because they produce an abnormally shaped LDL receptor. produce too many LDL receptors. don't produce enough LDL receptors. don't produce any LDL receptors.

don't produce enough LDL receptors.

Turner syndrome occurs in males. females.

female.

A carrier of a genetic disorder who does not show symptoms is likely to be _____ to transmit it to offspring. heterozygous for the trait and able heterozygous for the trait and unable homozygous for the trait and able homozygous for the trait and unable

heterozygous for the trait and able

People afflicted with recessive disorders are born to parents who were homozygous for the trait. heterozygous for the trait. not afflicted at all by the disease. all of these are true.

heterozygous for the trait.

R is dominant to r, the offspring of the cross of RR with rr will be homozygous. heterozygous. be represented as RR. be represented as rr.

heterozygous.

All of the offsping of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is _____ to the allele for white flowers. dominant recessive codominant incompletely dominant

incompletely dominant

The genotype XYY represents a

males.

What is the SRY gene? master gene for male sex determination master gene for female sex determination mutated gene that causes breast cancer gene that regulates the cell cycle

master gene for male sex determination

Nondisjunction occurs when two chromosomes fuse into one. a portion of a chromosome breaks off and is lost. members of a chromomsome pair fail to separate. all chromosomes are lost during meiosis I.

members of a chromosome pair fail to separate.

Sex-linked conditions are more common in men than in women because the genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness. the sex chromosomes are more active in men than in women. men acquire two copies of the defective gene during fertilization. men need to inherit only one copy of the recessive allele for the condition to be fully expressed.

men need to inherit only one copy of the recessive allele for the condition to be fully expressed.

A breeding experiment in which the parental varieties differ in only one trait is called a(n) monohybrid cross. dihybrid cross. test cross. all of these.

monohybrid cross.

Most people afflicted with recessive disorders are born to parents who were both affected by the disease. subjected to some environmental toxin that caused the disease in their children. not affected at all by the disease. all of these are true.

not affected at all by the disease.

Where is the SRY gene found? on the X chromosome on the Y chromosome on chromosome 21 on chromosome 1

on the Y chromosome

How many sex chromosomes are in a human gamete? two three four one

one

Which of the following is a genetic test that tracks the inheritance pattern of a trait through multiple generations? ultrasound amniocentesis pedigree karotype

pedigree

Which plants in this figure must all be heterozygous? white-flowered plants in the P generation purple-flowered plants in the F1 generation purple-flowered plants in the F2 generation purple-flowered plants in the P generation

purple-flowered plants in the F1 generation

The alleles of a gene are found at _____ chromosomes. different loci on homologous the same locus on non-homologous the same locus on homologous different loci on non-homologous

the same locus on homologous