Biology test #6

diseases caused by single gene mutations

Genetic screening can be used to identify:

False

Genome-wide association scans compare the proteins of individuals with a disease to individuals without the disease.

X-linked; VIII

Hemophilia A is an example of a(n) _____ disease and is characterized by a lack of blood-clotting factor ____.

genotype

Scientists use the term ____________ to refer to the genetic makeup for that organism.

sickle cell anemia

hemoglobin molecules stick to each other

inversion

in some severe hemophilia A patients, a region in the factor VIII gene is reversed

inactivated X chromosome.

A Barr body in a mammalian female cell represents a(n)

two-point test cross

A ____ is best used to demonstrate the linkage of two genes.

incomplete dominance.

A cross of two medium height hybrid plants produces offspring that are dwarf, medium, and tall in a ratio of 1:2:1. This is an example of

pleiotropy.

A gene that controls seed coat color in peas also determines the susceptibility of these peas to a particular disease. This situation is referred to as

The loci for wing length and body color are on the same chromosome.

A heterozygous fruit fly with normal wings and a gray body (VvBb) is crossed with homozygous flies with vestigial wings and black bodies (vvbb). Out of 800 total F1 progeny, 296 are normal gray, 328 are vestigial black, 99 are normal black, and 77 are vestigial gray. What is the best explanation for this result?

dihybrid cross.

A heterozygous fruit fly with normal wings and a gray body (VvBb) is crossed with homozygous flies with vestigial wings and black bodies (vvbb). This type of cross is known as a

XXY karyotype; fertile male

A karyotype reveals that an individual is XYY. Based on your knowledge of human genetics, you correctly conclude that this individual has ____, and is a phenotypically _____.

True

A male is neither homozygous nor heterozygous for his X-linked alleles; instead, he is always hemizygous.

Dihybrid cross

A mating between individuals with different alleles at two loci is known as?

either A or a.

A pear plant with the genotype Aa can produce gametes containing

False

A test cross is performed to determine phenotype.

alleles

Alternative forms of a gene are called ___________.

Allele

Alternative gene variants

15; father

An individual who inherits the specific chromosome ____ deletion from his/her ____ will most likely have Prader-Willi syndrome rather than Angelman syndrome.

meiotic nondisjunction

Autosomal aneuploidies arise by:

its effects are so lethal as to cause spontaneous abortion early in pregnancy.

Autosomal monosomy is not seen in live births because:

Three

Blood types A, B, AB, and O are controlled by how many alleles representing a single locus?

false

Dominant traits remove recessive traits when both are present in the same individual.

True

Dosage compensation is defined as the genetic phenomenon that allows females, who carry two copies of an X-linked gene, to have a phenotype that is equivalent to that of males, who only have one copy of the X-linked gene.

trisomic

Down syndrome is an example of a ____ condition.

the presence of 47 chromosomes per somatic cell

Down syndrome is characterized by:

population studies of large extended families

Human genetics can be most effectively studied using:

true

If a cell has two X chromosomes, XIST will become active in one of them, producing a special type of regulatory RNA molecule known as long noncoding RNA..

3/8

If a couple is planning on having three children, what is the probability that only one will be male?

Green

In Mendel's Experiment Results for Seven Characters, what was the dominant trait for pod color of the peas?

green

In Mendel's Experiment Results for Seven Characters, what was the dominant trait for pod color of the peas?

reversed

In a chromosomal inversion, a segment of a chromosome is:

36

In a two-point test cross, 36 of the offspring were recombinant types. The remaining 64 offspring were parental types. How many map units separate the two loci?

True

In fragile X syndrome, the fragile X gene contains a nucleotide triplet that repeats 200 to 1000 times.

the expression of a gene in the progeny depends upon which parent the gene is inherited from.

In genomic imprinting:

False

In humans, a mutation in the phenylalanine hydroxylase gene causes phenylketonuria (PKU), which is characterized by a wide variety of medical problems. This is an example of epistasis.

abnormal mucous secretions occur throughout the body systems.

In individuals with cystic fibrosis:

multiple alleles.

In rabbits, coat color is governed by four alleles: C for dark gray, Cch for chinchilla, Ch for Himalayan, and c for white. This is an example of

false

In trisomy 21, while all genetic information is intact, a abnormal copy of this chromosome creates a genetic imbalance that causes abnormal physical and mental development.

True

Polyploidy may arise from the failure of chromosomes to separate during cell division or by the fertilization of an egg by more than one sperm.

may be the result of more than one sperm fertilizing an egg

Polyploidy:

on cells of an in vitro fertilized embryo

Preimplantation genetic diagnosis is done:

deletion

Jacobsen syndrome, in which part of chromosome 11 is missing

the number of chromosomes in an individual

Karyotyping is useful for determining:

False

Males with Klinefelter syndrome lack a Barr Body.

False

Mendel's principle of independent assortment describes the separation of paired factors during the formation of gametes.

false

Mendel's principle of independent assortment describes the separation of paired factors during the formation of gametes.

Turner

Persons having an XO karyotype are sterile females. They have ____ syndrome.

reciprocal translocation

Philadelphia chromosome, in which parts of chromosomes 9 and 22 switch places; strongly associated with chronic myelogenous leukemia

presence of multiple sets of chromosomes

Polyploidy is the:

False

Sickle cell anemia and cystic fibrosis are examples of a homozygote advantage.

autosomal recessive; accumulation of lipids in brain cells

Tay-Sachs disease is a(n) ____ disease that results in blindness, intellectual disability, and death due to ____.

False

The Human Genome Project was completed in 2012 and revealed a genomic map of 38 million SNPs.

homologous chromosomes segregate during meiosis.

The chromosome theory of inheritance, developed by Sutton and Boveri, provided an explanation for Mendel's principle of segregation by proposing that

Genetic variation

The differences in traits observed in parents versus offspring

Phenotype

The expression of a trait in an organism

Genotype

The genetic composition of an organism

True

The science of comparative genomics to study human gene function is possible because much of the human genome is conserved among other closely related species.

3 tall: 1 short.

The height of pea plants from a cross between parent plants heterozygous for height, in which tall is dominant, would be

25,000; 2%

The human genome contains about ____ genes, which comprises about _____ of the genome.

Heredity

The inheritance of traits from one generation to the next

autosomal recessive

The inheritance pattern demonstrated by the pedigree in accompanying figure is:

crossing- over

The offspring of two heterozygous gray-bodied, normal-winged flies should be 50% gray-bodied/normal wings (BbRr) and 50% black-bodied/vestigial wings (bbrr) because these alleles are linked. Suppose a small number, say 15%, of the offspring are instead black-bodied with normal wings. This is most likely the result of

crossing-over.

The offspring of two heterozygous gray-bodied, normal-winged flies should be 50% gray-bodied/normal wings (BbRr) and 50% black-bodied/vestigial wings (bbrr) because these alleles are linked. Suppose a small number, say 15%, of the offspring are instead black-bodied with normal wings. This is most likely the result of

its locus.

The physical location of a gene on a chromosome is called

False

The presence of two X chromosomes supports the existence of a genetic locus.

False

The product rule is used to determine the probability that two parents with a Bb genotype will have a child who also has the Bb genotype. ​

presence of a Y chromosome.

The sex of a human is determined by the

sex chromosomes.

The sex of most mammals, birds, and insects is determined by

nondisjunction

The sperm in the figure below were most likely produced by:

genetics

The study of heredity

monosomic

Turner syndrome is an example of a __________ condition

1 homozygous healthy:1 carrier

What are the predicted phenotypes of the female children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Use the Punnett square to verify your answer.)

1 hemophilia:1 healthy

What are the predicted phenotypes of the male children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Use the Punnett square to verify your answer.)

PKU and alkaptonuria

Which of the following are inborn errors of metabolism?

Her mother is a carrier and her father has the disease.

Which of the following must be true for a female to have hemophilia?

Bb and bb

Which of the following represents the possible genotype(s) resulting from a cross between a heterozygous individual (Bb) and one that is homozygous (bb)?

Consanguineous matings are prohibited by half of U.S. states due to the increased risk of autosomal recessive alleles.

Which statement accurately characterizes an ethical consideration surrounding human genetics?

The mother breaks down phenylalanine for both herself and her fetus.

Why are most infants with phenylketonuria usually healthy at birth?

Its symptoms do not typically show until after the individual has had children.

Why has the dominant mutant allele for Huntington's disease been able to persist in human populations despite its devastating effects?

Polygenic inheritance

____ refers to multiple independent pairs of genes having similar and additive effects on the same characteristic.

hemophilia A

abnormality in a blood clotting protein

Tay-Sachs disease

absence of an enzyme to break down normal membrane lipid

translocation

de la Chapelle syndrome, in which an unequal crossing over event between the X and Y chromosomes during spermatogenesis results in the transfer of part of the Y chromosome to the X chromosome, resulting in an XX male

Phenylketonuria

defect in amino acid metabolism

cystic fibrosis

defect in the protein that regulates chloride transport across cell membranes