chapter 19

If two individuals homozygous dominant for this trait have a child, what is the chance that the child will not be able to roll his tongue?

0%

A couple is planning to have a child. The female is a carrier for hemophilia; the male does not have hemophilia. What is the chance that a female child will never develop hemophilia?

100%

If an individual homozygous dominant for this trait has a child with an individual who cannot roll his tongue, what is the chance that the child will have a heterozygous genotype?

100%

If an individual homozygous dominant for widow's peak has a child with an individual heterozygous for widow's peak, what is the chance that the child will have a widow's peak?

100%

If two individuals heterozygous for this trait have a child, what is the chance that the child will not be able to roll his tongue?

25%

Cystic fibrosis is a genetic disorder that results from the inheritance of two recessive alleles. What is the chance that a child will inherit the disorder if one parent is heterozygous for this gene and one parent has cystic fibrosis?

50%

If an individual homozygous dominant for widow's peak has a child with an individual heterozygous for widow's peak, what is the chance that the child will have a homozygous dominant genotype?

50%

Red-green color blindness is an X-linked recessive disorder. Assume that a mother is a carrier and a father is color-blind. What is the chance that their son will inherit red-green color blindness?

50%

a.comondinance

AB blood type

A recessive trait that is inherited through complete dominance can occur only if both parents are heterozygous for the trait.

F

Alleles are alternative versions of chromosomes.

F

Linked genes are not influenced by crossing-over during meiosis

F

Mendel's law of independent assortment states that genes separate from each other during gamete formation so that each sperm or egg gets only one unit of each pair.

F

________ testing refers to the analysis of an individual's genetic material to determine predisposition to a particular health condition.

Genetic

A Punnett square can be used to determine possible phenotypic ratios of offspring given a particular combination of parental alleles.

T

A deletion occurs when a piece of chromosome breaks off and is lost.

T

If alleles for the same gene are different in the same person, that individual is heterozygous for the trait.

T

In incomplete dominance, the phenotype of the heterozygous genotype is an intermediate between the phenotype of either homozygous genotype.

T

In the human male, genotype and phenotype associated with the genes on the X chromosome are determined by the one X chromosome he inherits from his mother.

T

Polygenic inheritance depends on gene products from multiple genes.

T

A recessive allele associated with chromosome 15 causes an enzyme deficiency disease called

Tay-Sachs

A father is blood type B and a mother is blood type A. They have a child with blood type O.

The father must be BO and the mother must be AO.

Which one of the following is TRUE regarding an individual who has inherited one sicklecell gene and one normal gene for hemoglobin?

The individual is more likely to resist malaria than an individual with two normal genes for hemoglobin

Which of the following genotypes results in a female phenotype

XO

d. klinefelter syndrome

XXY

b. Turner syndrome

a X chromosome; no Y or additional X chromosome

If a piece of chromosome breaks off during mitosis or meiosis and does not reattach, the event is called

a deletion

The flower color in this plant is inherited by incomplete dominance. If a red flower that is homozygous dominant is crossed with a white flower that is homozygous recessive, the color of the offspring flowers will be expected to be

all pink

Variations of homologous genes that result in differences in structure and function are

alleles

alternative versions of the same gene are

alleles

What is the significance of crossing-over, independent assortment, and random fertilization?

an increase in the genetic diversity of gametes and zygotes

c.sex influenced trait

baldness

If a plant is inherited by complete dominance where homozygous dominant is a red flower color and homozygous recessive is a white flower color, what must the parents' genotypes be if the offspring was 25% white and 75% red?

both heterozygous

Which of the following human traits is an example of codominance?

both sickle cell anemia AB blood type

Genes located on the same chromosome are not always inherited together because of the process of ________, which occurs during meiosis; this process "reshuffles" the genes.

crossing over

A(n) ________ in a chromosome is often lethal and occurs when a part of chromosome breaks off or is lost.

deletion

Genes represent the set of instructions for the expression of one or more traits human beings and influence human behaviors by

directing the synthesis of protein products that influence but do not directly cause most human behaviors.

b.non disjunction

down syndrome

An individual who inherits three copies of chromosome 18 will develop ________ syndrome

edwards

The law of segregation states that

genes separate from each other during gamete formation so that each sperm and egg receive only one allele from each pair.

a _________ refers to the complete set of DNA within the chromosomes of an individual

genome

A phenotype is determined by ________ and ________.

genotype; environmental factors

If the two alleles of a particular gene pair are the same, the individual is ________ for that gene.

homoysygous

If both alleles of a particular gene are identical, the person is said to be

homozygous

An example of a genotype is

homozygous dominant.

d.polygenic inheritance

human eye color

g. inheritance of a dominant lethal alle

huntington disease

Which one of the following genetic disorders is caused by the inheritance of a dominantlethal allele?

huntingtons dissease

in _______ dominance, the phenotype of the heterozygous genotype is an intermediate between the phenotype of either homozygous genotype

incomplete

The offspring resulting from a cross between a nearly white horse (cc) and a chestnutcolored horse (CC) is of an intermediate color (between white and chestnut). Which one of the following patterns of inheritance best explains this?

incomplete dominance

In 2008 the U.S. Congress passed GINA, an act that prevents insurance companies from A) requiring genetic testing for potential policy holders with a family history of certain types of genetic disorders. B) raising the rates

increasing insurance costs for healthy individuals based on the results of genetic testing.

A display of an individual's chromosomes is known as a(n) ________.

karyotype

Genes for different traits located on the same chromosome in close proximity are called ________ genes.

linked

During embryological development, if a certain gene on the Y chromosome is activated during the sixth or seventh week of development, the embryo will develop into a ________.

male

In polygenic inheritance,

multiple alleles and genes contribute to a phenotype.

Which of the following is most likely involved in the determination of intelligence?

multiple genes and the environment

Failure of homologous chromosomes or sister chromatids to separate properly is called ________.

nondisjunction

Failure of sister chromatids to separate properly is called

nondisjunction

Place the following in order from smallest, simplest, least complex, to largest and most inclusive.

nucleotide, gene, chromosome, genome

Red-green color blindness is an X-linked recessive disorder. Assume that a mother is a carrier and a father is color-blind. What is the chance that their son will inherit red-green color blindness?

one dominant allele, one recessive allele

The inheritance of a trait that is determined by many genes acting together, such as eye color, is called ________ inheritance.

polygenic

The Punnett square is a useful tool for

predicting the ratios of possible genotypes of a particular combination of alleles.

Cystic fibrosis is the most common fatal genetic disease in North America and results in what type of allele located on chromosome 7?

recessive

f.x linked ineritance

red green color blindness

Polygenic traits display phenotypes that

represent a continuous range within the population.

a. tay sachs

ressesive allele on chromosome 15

According to Mendel's law of ________, genes of a gene pair separate from one another during the formation of gametes.

segregation

e.incomplete dominance

staight vs curly vs wavy hair in humans

Which of the following is characteristic of Klinefelter syndrome?

sterility and mild mental impairment

The trend toward increased height and weight due to improved nutrition in certain human populations is an example of the effect of ________ on phenotypes.

the environment

A phenotypic trait is considered sex-linked when

the genes for the phenotype occur on X or Y chromosomes

Alterations in chromosome number can occur with any chromosome, but most alterations are not seen in human populations because

they are lethal during fetal development

The process by which a piece of a chromosome breaks off and then attaches to another chromosome is referred to as ________

translocation

When a piece of chromosome breaks off and reattaches at another site on the same or another chromosome, this is called

translocation

A person born with Edwards syndrome has a genotypic condition identified as

trisomy 18

c. edwards syndrome

trisomy 18

e. down syndrome

trisomy 21

Which one of the following syndromes results in an individual with a nearly normal female phenotype and a tendency to develop mild mental retardation?

trisomy-x syndrome