Module 6 Study Guide - Bio 103

FISH distinguishes chromosomes by using more than one fluorescent-tagged RNA strand, which will bind to complementary DNA sequences on a specific chromosome.

False

Geneticists study pedigrees in order to predict how traits determined by phenotype are inherited from one generation to the next.

False

Genotype can always be inferred from phenotype.

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.

False

Nondisjunction of the XY pair during the first meiotic division can produce sperm with 2 X chromosomes and 2 Y chromosomes.

False

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

False

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

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.

False

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

Green

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

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

The position of a specific gene on a chromosome can be determined by:

fluorescent in situ hybridization

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

genotype

Refer to the accompanying figure. Based on the phenotypes of the third generation, the genotype of the father in the second generation must be:

heterozygous for albinism

The genotypes of the normal females in the second generation in accompanying figure are:

heterozygous for albinism

Individuals who are ____ for sickle cell hemoglobin tend to be ____ resistant to falciparum malaria but do not experience the effects of sickled red blood cells.

heterozygous; more

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

incomplete dominance.

When true breeding red tulips are crossed with true breeding white tulips, the progeny have pink flowers. This is an example of

incomplete dominance.

Translocation occurs when:

part of a chromosome breaks off and attaches to a nonhomologous chromosome

Mating a pure-bred pink rose plant with a pure-bred pink rose plant will produce

plants with only pink roses.

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

pleiotropy

The ability of a single gene to have multiple effects is known as _____.

pleiotropy

A couple who does not have cystic fibrosis but are both heterozygous has already had three girls with cystic fibrosis, and are hoping to have a healthy child for their fourth. What are the chances that the fourth child will be a healthy male?

3/8

If a couple is planning on having two children, what is the probability that both will be male?

1/4

What is the probability that two lizards heterozygous for stripes on their tails (Ss) will produce homozygous offspring with no stripes (ss)?

1/4

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

15; father

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

25 % hemophilia: 75% normal

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

3/8

The normal human karyotype contains ____ total chromosomes, consisting of ____ autosomes and ____ sex chromosomes.

46; 22; 2

A lizard with a striped tail and a normal head is crossed with one having a normal tail and a spotted head. All the F1 progeny are normal (no stripes or spots). What progeny are expected from a cross of the F1 progeny? Assume that the genes conferring stripes and spots were on different chromosomes.

9 normal : 3 striped : 3 spotted : 1 striped and spotted

The color of certain genetically identical hydrangea flowers ranges from blue to purple to pink, depending on the level of aluminum in the soil. In which of the following types of soil is aluminum less soluble, and the flowers pink?

Alkaline soils

____ are alternative forms of a gene that govern the same feature, such as eye color, and occupy corresponding positions on homologous chromosomes.

Alleles

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

Bb and bb

Which statement accurately characterizes an ethical consideration surrounding human genetics?

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

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

Dihybrid cross

Which of the following statements about dosage compensation is false?

Dosage compensation is a mechanism that makes equivalent the two doses in the male and the single dose in the female.

What explains the viability of individuals with aneuploidies for the sex chromosomes?

Dosage compensation, by which one X chromosome per cell is inactivated.

Which describes the interaction between genes such that the presence of certain alleles in one locus affects the expression of certain alleles in the other locus?

Epistasis

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

False

What is the current status of gene therapy?

It is being evaluated to assess the risks associated with potential side effects.

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

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

Which of the following are inborn errors of metabolism?

PKU and alkaptonuria

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?

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

Why are most infants with phenylketonuria usually healthy at birth?

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

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

Three

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.

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..

True

In reciprocal translocation, two homologous chromosomes exchange segments.

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.

True

The theory of blending inheritance was shown to be false by Mendel's observations of dominant and recessive alleles.

True

The cells of female mammals, including humans, contain two __________.

X chromosomes

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

X-linked; VIII

What are the possible genotypes of a female child from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics?

XHXH or XHXh

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 _____.

XXY karyotype; fertile male

Aneuploidies describe:

a condition in which an extra chromosome is present or one is absent

In individuals with cystic fibrosis:

abnormal mucous secretions occur throughout the body systems.

Nondisjunction during mitosis leads to:

an individual with a clone of abnormal cells.

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

autosomal recessive

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.

Gene targeting has been used in mice to produce strains that were either homozygous or heterozygous for ____.

cystic fibrosis

Jacobsen syndrome, in which part of chromosome 11 is missing

deletion

Cri du chat syndrome arises from:

deletion of part of chromosome 5

Genetic screening can be used to identify:

diseases caused by single gene mutations

A pear plant with the genotype Aa can produce gametes containing

either A or a.

A gene that affects, prevents, or masks the expression of a gene at another locus is a(n) ____ gene.

epistatic

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

inversion

A fragile site:

is associated with cancerous cells

Autosomal monosomy is not seen in live births because:

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

If an allele is dominant, then

its phenotype masks the expression of the recessive allele in a hybrid.

Nearly half of the pregnancies that end in miscarriage have:

major chromosomal abnormalities

Polyploidy:

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

Autosomal aneuploidies arise by:

meiotic nondisjunction

Turner syndrome is an example of a __________ condition.

monosomic

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

multiple alleles.

Huntington's disease is caused by a:

nucleotide triplet repeat

Human genetics can be most effectively studied using:

population studies of large extended families

The sex of a human is determined by the

presence of a Y chromosome.

Polyploidy is the:

presence of multiple sets of chromosomes

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

reciprocal translocation

All calico cats are female because

the calico phenotype is caused by random X chromosome inactivation.

The probability that two genes will be separated by crossing-over is related to

the distance between the two genes on the chromosome.

In genomic imprinting:

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

Karyotyping is useful for determining:

the number of chromosomes in an individual

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

translocation

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

two-point test cross