college bio ch 14 & 15 TEST - genetics

In pea plants, the tall phenotype is dominant to the dwarf phenotype. If a heterozygous pea plant is crossed with a homozygous tall pea plant, what is the probability that the offspring will be dwarf in size?

0

Having polydactyly (extra digits on hands and feet) is a dominant trait. A man has polydactyly. His wife and oldest daughter do not have polydactyly. The couple's second child has polydactyly. What is the probability that their next (third) child will have extra digits?

1

A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the typical number of digits. Remember that extra digits is a dominant trait. What fraction of this couple's children would be expected to have extra digits?

1/2

A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color blind has children with a color-blind male. What is the probability that this couple's first son will be color blind?

1/2

Black fur in mice (B) is dominant to brown fur (b). Short tails (S) are dominant to long tails (s). What fraction of the progeny of crosses BbSs × BBss will be expected to have black fur and long tails?

1/2

Albinism is a recessive trait where an individual does not produce the pigment melanin. A man and woman both produce melanin, but both have one parent with albinism. What is the probability that their first child will have albinism?

1/4

Cinnabar eye color is an X-linked, recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a male having wild-type, red eyes, what percent of the F1 males will have cinnabar eyes?

100%

In maize (corn plants) a dominant allele I inhibits kernel color, while the recessive allele i permits color when homozygous. At a different locus, the dominant allele Pcauses purple kernel color, while the homozygous recessive genotype pp causes red kernels.If plants heterozygous at both loci are crossed, what will be the phenotypic ratio of the offspring?_____ colorless: _____ purple: _____ red

12:3:1

When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow-seeded. Which of the following genotypic ratios was expected when Mendel crossed the F1 yellow-seeded plants with green-seeded plants?

1:1

Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers, and the other has white, terminal flowers; all F1 individuals have red, axial flowers. Among the F2 offspring, what is the probability of producing plants with white axial flowers?

3/16

Poly-X Syndrome

47 chromosomes, no apparent physical abnormalities XXX

Polyploidy

A chromosomal alteration in which the organism possesses more than two complete chromosome sets.

Codominance

A condition in which neither of two alleles of a gene is dominant or recessive. AB blood type

Barr body

A dense object lying along the inside of the nuclear envelope in female mammalian cells, representing an inactivated X chromosome.

Which of the following statements correctly describes the terms monohybrid crossand dihybrid cross?

A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied.

hemizygous

A gene present on the X chromosome that is expressed in males in both the recessive and dominant condition

carrier

A person whose genotype includes a gene that is not expressed in the phenotype. heterozygous

Pleiotropy

A single gene having multiple effects on an individuals phenotype

Epistasis

A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited.

complete dominance example

A type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable. A pea plant with all purple flowers and a pea plant with all white flowers produce a pea plant with all purple flowers

Which of the following statements correctly explains the fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment?

All of the genes controlling the traits were on different chromosomes.

polygenic inheritance

An additive effect of two or more genes on a single phenotypic character. Male pattern baldness, glaucoma, epilepsy, HTN, schizophrenia, height, skin color

sex linked

An inheritance pattern in which traits are controlled by genes located on the X chromosome. color blindness and hemophilia

Gregor Mendel

Augustinian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)

In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. The Rh phenotype is recorded by stating "positive" or "negative" after the individuals ABO blood type. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following phenotypes is possible for the father?

B positive

Thomas H Morgan

Discovered the first X-linked gene in Drosophilia melanogaster. Studied crosses involving X-linked genes.

Which of the following describes why Mendel continued some of his experiments into the F2 or F3 generation?

Following multiple generations allowed him to determine whether a recessive trait would reappear.

In a particular plant, green seed color is dominant to blue. If two plants with green seeds were crossed and resulted in 302 green and 98 blue seed plants, what was the most probable genotype of each parent?

Gg × Gg

Which of the following scenarios describes an example of epistasis?

In many mammals one genotype (ee) prevents any fur color from developing.

Which of the following statements about the law of independent assortment is correct?

It describes the inheritance of different genes relative to one another. Submit

Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes eye problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information?

It is pleiotropic.

Which of the following statements correctly explains the observation that parents with two different phenotypes produced offspring with a phenotype that is a blend of the two parental varieties?

Neither of the parental alleles is dominant over the other. Submit

Why did all of the F1 offspring of Mendel's purple and white flowered pea cross always look like one of the two parental varieties?

One allele was dominant.

One of two major forms of neurofibromatosis results from inheriting a dominant allele of a gene with affected individuals having phenotypes that range from mild to very severe. Which of the following is the best explanation for why a young child is the first in her family to be diagnosed with a severe form of the condition?

One of the parents has a mild expression of the gene.

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients' muscles weaken over time because they have a lack or decreased levels of dystrophin, a muscle protein. Which of the following correctly predicts the probability of muscular dystrophy in female children?

One-half of the daughters of an affected man and a carrier woman would have this condition. Submit

Which of the following statements regarding gene linkage is correct?

The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.

Mendel crossed true breeding yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?

The green allele is recessive to the yellow allele.

norm of reaction

The range of phenotypes produced by a single genotype, due to environmental influences. an individual plant might receive either more or less water during its growth cycle, or the average temperature the plants are exposed to might vary across a range.

Which of the following sentences state a significant conclusion that Gregor Mendel drew from his experiments with pea plants?

Traits are inherited in discrete units and are not the result of "blending."

Which of the following statements correctly describes how Mendel explained why traits disappeared in the F1 generation and then reappeared in the F2 generation?

Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1.

Which of the following is an example of monosomy in humans?

Turner syndrome

Monosomy in females with only one X results in

Turner's syndrome

Red-green color blindness is an X-linked recessive trait in humans. Two people with normal color vision have a son with colorblindness. Given this information, the genotypes of the parents are ________.

XNXn and XNY

Klinefelter syndrome

XXY

Jacob's Syndrome

XYY

Down Syndrome

a condition of mild to severe intellectual disability and associated physical disorders caused by an extra copy of chromosome 21, trisomy 21

The SRY gene is best described as ________.

a gene present on the Y chromosome whose product regulates male development

The figure shows the pedigree of a family. Dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. Males are represented by squares, females by circles.Based on this pedigree, this trait is most likely inherited ________.

as a dominant trait

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. Also, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. The relationship between genes S and N is an example of which of the following inheritance patterns?

epistasis

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following inheritance patterns?

incomplete dominance

Males are more often affected by X-linked traits than are females because ________.

males are hemizygous genes on the X chromosomes

Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?

pleiotropy

A radish is a root vegetable that produces flowers that may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red-flowered, long radishes long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to exhibit which of the following phenotypes?

purple and long

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (CRCW) offspring of red (CRCR) and white (CWCW) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?

roan × roan

Which of the following phenotypes is an example of polygenic inheritance?

skin pigmentation in humans

multiple alleles

three or more forms of a gene that code for a single trait ABO blood type

In cats, an X-linked locus is responsible for fur color. There are two known alleles at this locus. One results in black fur color; the other results in orange fur color. A heterozygote animal has patches of orange and black fur (tortoiseshell). Which coat color phenotypes are expected from the cross of a black female and an orange male?

tortoiseshell females; black males

The chromosomal alteration that results from a chromosome fragment joined to a nonhomologous chromosome is called a ________.

translocation

A brown dog crossed with a yellow dog produced 12 brown offspring. A second brown individual was obtained. When the yellow dog was crossed with this animal, six brown and six yellow offspring were born. Which of the following best explains the results of the second cross?

yellow is a recessive trait; brown is a dominant trait

Albinism is a recessive trait where an individual does not produce the pigment melanin. A man and woman who both produce melanin have one child out of three who has albinism. What are the genotypes of the man and woman?

Both parents must be heterozygous.