Chapter 14: Mendel and the Gene Idea

A family tree that describes traits in families is called a __________.

quantitative character

Punnett square analysis

qualitative character

pedigree analysis

standard deviation

pedigree analysis

Fetal cells may be removed along with fluid from the womb by a process known as __________.

amniocentesis

chorionic villus sampling

testcrossing

karyotyping

sonogramming

amniocentesis

The effect of the environment on a phenotype is referred to as __________.

multifactorial

polygenetic

multiple allelic

epistatic

pleiotropic

multifactorial

Mendel studied __________, heritable features that vary among individuals; each variant is called a __________.

characters; flower

flowers; character

None of the listed responses is correct.

traits; character

characters; trait

characters; trait

Besides the fact that pea plants have a short generation time, the key to Mendel's successful plant-breeding experiments was that pea plants usually __________.

cross-pollinate

reproduce by making clones

wind-pollinate

self-pollinate

animal-pollinate

self-pollinate

Human blood groups are governed by three alleles, A, B, and O. A and B are codominant and O is recessive to both. A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes?

AB or O

A, B, or O

AB only

A, B, AB, or O

A or B only

A, B, AB, or O

In a typical pea experiment, two true-breeding plants with distinct traits of a single character are called the __________, and the offspring are called the __________, which will always be __________.

- F1 (or first filial) generation; F2 (or second filial) generation; true breeding

- P (or parental) generation; F2 (or second filial) generation; true breeding

- F1 (or first filial) generation; F2 (or second filial) generation; hybrid

- P (or parental) generation; F1 (or first filial) generation; hybrid

- P (or parental) generation; F1 (or first filial) generation; true breeding

- P (or parental) generation; F1 (or first filial) generation; hybrid

In Labrador retrievers, a dog that has the genotype BBee, where BB produces black-pigmented fur and ee produces yellow-pigmented fur, would have __________ fur and would exhibit __________.

brown; codominance

yellow; incomplete dominance

brown; epistasis

yellow; epistasis

black; dominance

yellow; epistasis

In humans, height and skin color have continuous variation in the population because of __________.

incomplete dominance

multiple alleles

codominance

polygenic inheritance

epistasis

polygenic inheritance

In people with sickle-cell disease, red blood cells break down, clump, and clog the blood vessels. The blood vessels and the broken cells accumulate in the spleen. Among other things this leads to physical weakness, heart failure, joint pain, and brain damage. Such a suite of symptoms can be explained by __________.

- side effects of the drugs used to cure sickle-cell disease

- an epistatic interaction between the sickle-cell allele and a proteolytic enzyme gene

- the pleiotropic effects of the sickle-cell allele

- the polygenic nature of sickle-cell disease

- a bacterial infection interacting with the sickle-cell allele

- the pleiotropic effects of the sickle-cell allele

A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that are __________.

completely dominant

codominant

polygenic

epistatic

nonhomologous

codominant

__________ occurs when a single gene affects the phenotype of many characters in an individual.

Epistasis

Polygenic inheritance

Incomplete dominance

Codominance

A pleiotropic effect

A pleiotropic effect

In incomplete dominance, the offspring __________.

- will resemble the dominant type 75% of the time

- will resemble the recessive type 50% of the time

- will resemble the recessive type 25% of the time

- will have an appearance that's intermediate between those of the two parental types

- will resemble the dominant type 50% of the time

- will have an appearance that's intermediate between those of the two parental types

The term "true-breeding plants" means __________.

- that self-pollinating plants will always produce the same trait of a particular character

- that Mendel obtained all of his information from true-breeding plants because they have the strongest character

- that pea plants choose with whom they mate

- that pea plants will produce plants that have a different trait of a particular character

- that pea plants will breed only with other pea plants

- that self-pollinating plants will always produce the same trait of a particular character

An alternative version of a gene is called a(n) __________.

genotype

allele

character

generation

phenotype

allele

If an organism that is homozygous dominant is crossed with a heterozygote for that trait, the offspring will be __________.

1/4 of the recessive phenotype

all homozygous dominant

all homozygous recessive

present in a 9:3:3:1 ratio

all of the dominant phenotype

all of the dominant phenotype

If a heterozygous plant is allowed to self-pollinate, what proportion of the offspring will also be heterozygous?

All of them

23

14

13

1/2

1/2

Huntington's disease is an example of a genetic disorder caused by __________.

- a lethal dominant allele that afflicts an individual later in life

- multiple alleles

- a late-acting recessive allele

- homozygous recessive alleles

- a nonlethal dominant allele

- a lethal dominant allele that afflicts an individual later in life

If the two traits that Mendel looked at in his dihybrid cross of smooth yellow peas with wrinkled green peas had been controlled by genes that were located near each other on the same chromosome, then the F2 generation __________.

- would have contained four phenotypes in a 9:3:3:1 ratio

- would have contained only individuals that were heterozygous at both loci

- None of the listed responses is correct.

- would have contained no individuals that were heterozygous at both loci

- would have deviated from the 9:3:3:1 phenotypic ratio that is predicted by the law of independent assortment

- would have deviated from the 9:3:3:1 phenotypic ratio that is predicted by the law of independent assortment

Achondroplasia, a type of dwarfism, and Huntington's disease are examples of __________, with the exception that the Huntington's allele is __________.

recessive inherited disorders; lethal

dominant inherited disorders; lethal

incomplete dominance; lethal

recessive inherited disorders; nonlethal

dominant inherited disorders; nonlethal

dominant inherited disorders; lethal

If a plant variety is true-breeding for a dominant trait, then __________.

- if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait

- the plant is heterozygous for the trait

- if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait

- if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny

- the variety is unable to mutate

- if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait

Human ABO groups are best described as an example of __________.

a pleiotropic effect

multiple alleles

autosomal dominant alleles

Mendelian dominant and recessive alleles

codominant alleles

multiple alleles

Which choice below is a basic difference between Mendel's particulate hypothesis and the hypothesis of blending inheritance?

- The blending inheritance hypothesis, but not the particulate hypothesis, maintained that after a mating, the genetic material provided by each of the two parents is mixed in the offspring, losing its individual identity.

- The blending inheritance hypothesis, but not the particulate hypothesis, maintained that the traits governed by genes in the egg are different from the traits governed by genes in the sperm.

- All of the listed responses are correct.

- The blending inheritance hypothesis, but not the particulate hypothesis, maintained that the two alleles at any given locus are always different.

- The blending inheritance hypothesis, but not the particulate hypothesis, maintained that mutation is the major source of new gene combinations.

- The blending inheritance hypothesis, but not the particulate hypothesis, maintained that after a mating, the genetic material provided by each of the two parents is mixed in the offspring, losing its individual identity.

A man who can roll his tongue and a woman who cannot roll her tongue have a son who can roll his tongue (R = can roll tongue; r = can't roll tongue). The son is curious about whether his father is homozygous or heterozygous for the tongue-rolling trait. Which of the following facts would allow him to know?

- His paternal grandfather and his paternal grandmother can both roll their tongues.

- His father's mother cannot roll her tongue.

- The son's own daughter cannot roll her tongue.

- The son's sister is a tongue roller.

- The son submits his own blood sample to a local genotyping lab, and they establish that he is heterozygous for the trait.

- His father's mother cannot roll her tongue.

Pea plants are tall if they have the genotype TT or Tt, and they are short if they have genotype tt. A tall plant is mated with a short plant. Which outcome below would indicate that the tall parent plant was heterozygous?

- There is not enough information to answer the question.

- The ratio of tall offspring to short offspring is 1:1.

- The ratio of tall offspring to short offspring is 3:1.

- All of the offspring are short.

- All of the offspring are tall.

- The ratio of tall offspring to short offspring is 1:1.

What kind of protection does the Genetic Information Nondiscrimination Act of 2008 provide the public with regard to the use of genetic information?

- The law mandates that people who undergo genetic testing are provided professional instruction so that they can make informed family decisions based on their test results.

- The law mandates that all expecting mothers must undergo fetal testing for genetic disorders regardless of their demographic status.

- The law guarantees that access to genetic counseling cannot be denied to U.S. citizens based on their race, sex, age, religious beliefs, or sexual orientation.

- The law prohibits the use of genetic test information to deny insurance coverage or employment to individuals.

- The law prohibits the use of genetic test information to deny insurance coverage or employment to individuals.

In addition to the ABO system, humans have other blood groups, including the MN system. Individuals who have alleles for both M and N show __________ for the M and N red blood cell surface antigens.

codominance

epistasis

polygenic inheritance

complete dominance

incomplete dominance

codominance

The F1 generation differed from the F2 in Mendel's experiments in that __________.

- all of the F1 showed the dominant phenotype, but only three-fourths of the F2 did

- all of the F1 showed the dominant phenotype, whereas only half of the F2 did

- one-half of the F1 showed the dominant phenotype, and three-fourths of the F2 did

- none of the F1 showed the dominant phenotype, but one-half of the F2 did

- all of the F1 showed the dominant phenotype, and all of the F2 showed the recessive phenotype

- all of the F1 showed the dominant phenotype, but only three-fourths of the F2 did

Color in squash is controlled by epistatic interactions in which color is recessive to no color. At the first locus white squash (W) is dominant to colored squash (w). At the second locus yellow (Y) is dominant to green (y). What is the phenotype of a squash with the genotype wwYy?

Yellow

White with yellow stripes

White

Green

Green with yellow stripes

yelloq

Mendel's law of segregation states that __________.

- only true-breeding plants can be bred with true-breeding plants

- the two alleles for a heritable character do not segregate during gamete formation and end up in the same gametes

- The law of segregation does not apply to pea plants.

- non-true-breeding plants can be bred with non-true-breeding plants

- the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes

- the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes