module 6 bio 103

Males with Klinefelter syndrome lack a Barr Body.

False

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

False

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.

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

genotype

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

green

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

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

Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What is the probability that they will have a child with purple eyes (assuming Martians have similar genetics to humans)?

0

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

1/4

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 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

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

Which of the following does NOT describe Mendel's research and proposed Model of Inheritance?

Factors may be expressed, hidden in a given generation or lost.

A test cross is performed to determine phenotype.

False

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.

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.

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

Mendel's principle of segregation states that

alleles separate from each other before forming gametes.

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

autosomal recessive; accumulation of lipids in brain cells

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

fluorescent in situ hybridization

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

dihybrid cross.

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.

f

Genotype can always be inferred from phenotype.

false

The debate over nature versus nurture in determining certain human characteristics can be explained by pleiotropic genes.

false

The physical location of a gene on a chromosome is called

its locus.

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

nondisjunction

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

t

In genomic imprinting:

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

What was revealed with the completion of the Human Genome Project?

the sequence of the entire human genome

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 genetics, map units express the distance between

two loci on a chromosome.

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

two-point test cross