Week 2- Quizzes, Animations, Clicker Questions

Question 1

Homologous chromosomes usually have the same arrangement of genes along their length.

True

False

Answer 1

True

Question 2

Genes located along the X chromosome:

are called X-linked genes.

are always recessive to genes located in the Y chromosome.

have a full set of complementary alleles in the Y chromosome.

are contributed solely by the female parent.

Answer 2

are called X-linked genes.

Question 3

During meiosis in the female, sex chromosomes segregate to produce two types of eggs: X-bearing eggs and Y-bearing eggs.

True

False

Answer 3

False

Question 4

All organisms have either an X or Y chromosome, as these chromosomes are solely responsible for determining the sex of an individual. Mendel’s failure to identify X and Y chromosomes in his pea plants invalidated a portion of the data he collected.

True

False

Answer 4

False

Question 5

Which of the following is a possible human genotype that could result from nondisjunction of the sex chromosomes in one of the parental gametes?

XXX

XYY

XO

XXY

All of these choices are correct.

Answer 5

All of these choices are correct.

Question 6

Review the pedigree shown in Figure 17.7 and choose the most accurate statement about the inheritance of an X-linked recessive mutation.

The brothers of affected males are always affected.

For rare X-linked traits, most of the affected individuals are males.

Daughters of affected males are always affected.

The offspring of an affected male are usually affected.

The sons of the sisters of affected males will always be affected.

Answer 6

For rare X-linked traits, most of the affected individuals are males.

Question 7

A heterozygous female harboring one mutant allele for hemophilia is called a(n) _____ for that trait.

messenger

harborer

homozygote

carrier

unaffected female

Answer 7

carrier

Question 8

Sometimes homologous chromosomes fail to separate normally during meiosis I, a process called:

nontransferrance.

unijunction.

chromosome separation.

nondisjunction.

conjugation.

Answer 8

nondisjunction.

Question 9

Which of the following is true of a cross involving a sex-linked gene but not of a cross involving an autosomal gene?

A Punnett square cannot be utilized for illustrating the possible outcomes of a cross involving a sex-linked gene.

The phenotype outcomes of female offspring compared to males can be different.

Recombination or crossing over cannot take place between sex chromosomes.

Both parents have two copies of a sex-linked gene.

Only autosomal genes observe the law of segregation.

Answer 9

The phenotype outcomes of female offspring compared to males can be different.

Question 10

For most genes on the human X chromosome, what percent of XY males with a mutant allele on the X chromosome will express the mutant phenotype?

A., 0%

B., 25%

C., 50%

D., 100%

E., There is insufficient data to predict

Answer 10

D., 100%

Question 11

In humans, fruit flies, and many other organisms, most of the genes on the X chromosome are not found on the Y chromosome.

A., true

B., false

Answer 11

A., true

Question 12

If an XY male carries a mutation on his X chromosome, __________ will receive the mutant X.

A., all of his sons

B., all of his daughters

C., all his sons and daughters

D., half his sons and half his daughters

Answer 12

B., all of his daughters

Question 13

A normal female who carries a recessive X-linked allele for hemophilia will pass it on to:

A., all of her daughters.

B., half of her daughters.

C., all of her sons.

D., half of her sons.

E., half of both her sons and daughters.

Answer 13

E., half of both her sons and daughters.

Question 14

Color blindness is a recessive X-linked trait in humans. In a family where the mother is color-blind and the father is normal, the probability of their having a color-blind son is:

A., 0.

B., 1.

C., 1/4.

D., 1/2.

E., 1/16.

Answer 14

B., 1.

Question 15

Color blindness is a recessive X-linked trait in humans. In a family where the mother is heterozygous for color blindness and the father is color-blind, the probability of their having a color-blind daughter is:

A., 0.

B., 1.

C., 1/4.

D., 1/2.

E., 1/16.

Answer 15

D., 1/2.

Question 16

The genotype of a fetus can be screened for SNPs associated with some diseases.

False

True

Answer 16

True

Question 17

After doing PCR on the same region between two individuals, you notice that each person’s DNA yielded pieces of different sizes. Which of the following is the MOST likely explanation?

This is an example of VNTRs.

A mistake was made during gel electrophoresis.

This is an example of RFLPs.

A mistake was made during the PCR.

None of the answer options is correct.

Answer 17

This is an example of VNTRs.

Question 18

Mutations that destroy or create a cleavage site for a restriction enzyme are the source of:

variable number tandem repeats.

single-nucleotide polymorphisms.

restriction fragment length polymorphisms.

copy-number variants.

Answer 18

restriction fragment length polymorphisms.

Question 19

The maximum frequency of recombination between two genes is:

50%.

100%.

75%.

25%.

0%.

Answer 19

50%.

Question 20

Two genes, A and B, are found in the same chromosome. One chromosome has alleles A and B, while its homolog has alleles a and b. If genes A and B are so closely linked that the recombination frequency is 0%, only AB and ab gametes will be produced during meiosis.

False

True

Answer 20

True

Question 21

Physical exchange between homologous chromosomes (crossover) occurs during the four-strand stage of meiosis.

False

True

Answer 21

True

Question 22

In crosses involving linked genes, recombinant offspring result from:

Mendelian segregation.

sex-linked inheritance.

independent assortment of alleles.

a crossover.

Mendelian segregation and independent assortment of alleles.

Answer 22

a crossover.

Question 23

Genes that are close together in the same chromosome:

tend to assort independently.

assort primarily independently, but will, very rarely, be transmitted together.

tend to be transmitted together.

are present only in X chromosomes.

tend to be transmitted together, and are present only in X chromosomes.

Answer 23

tend to be transmitted together.

Question 24

Which of the following is least likely to produce recombinant chromosomes?

A., crossovers between homologous chromosomes

B., crossovers between non-sister chromatids

C., crossovers between sister chromatids

Answer 24

C., crossovers between sister chromatids

Question 25

During which phase of meiosis do homologous chromosomes synapse with crossing-over between homologous chromosomes?

A., prophase I

B., prophase II

C., both prophase I and prophase II

D., neither prophase I nor prophase II

Answer 25

A., prophase I

Question 26

The _______ two loci are on a chromosome, the more likely they will be separated by crossover events during gamete formation, and thus the frequency of recombination between loci on a chromosome can be used to measure the _________ between those loci.

A., farther apart; genetic distance

B., farther apart; number of crossovers

C., closer together; genetic distance

D., closer together; number of crossovers

Answer 26

A., farther apart; genetic distance

Question 27

Without the SRY gene, humans and other mammals would develop and retain the female sex organs and phenotype.

True

False

Answer 27

True

Question 28

The Y-linked trait of hairy ears has been passed down for many generations in a certain family. A hairy eared male in this family should definitely have:

male grandchildren with hairy ears.

a maternal grandfather with hairy ears.

uncles with hairy ears.

nephews with hairy ears.

a paternal grandfather with hairy ears.

Answer 28

a paternal grandfather with hairy ears.

Question 29

Imagine that a doctor sees a patient that is genotypically male, but is phenotypically female. How could this occur?

This patient likely carries a mutation in SRY that increases SRY protein levels, and a mutation in the X chromosome that decreases X chromosome-associated protein levels.

This patient likely carries a mutation in the X chromosome that increases X chromosome-associated protein levels.

This patient likely carries a mutation in the X chromosome that decreases X chromosome-associated protein levels.

This patient likely carries a mutation in SRY that decreases SRY protein levels.

This patient likely carries a mutation in SRY that increases SRY protein levels.

Answer 29

This patient likely carries a mutation in SRY that decreases SRY protein levels.

Question 30

The tips of the arms of the X and Y chromosomes share small regions of homology. Genes located in these regions are inherited in the same manner as the ones found in autosomes.

True

False

Answer 30

True

Question 31

A young man wants to determine if he is a descendant of Henry of Navarre and Eleanor of Aquitainetwo of his favorite historical characters. He sends a cheek swab to a DTC company and is offered a choice (due to funding): The company can assess either the sequence of the man’s Y chromosome or his mitochondrial DNA. Which should he choose?

It doesn’t matteran equal amount of genetic variation exists between different Y chromosome haplotypes and different mitochondrial haplotypes.

He should get his mitochondrial haplotype sequenced, given the genetic variation in mitochondrial sequences compared to Y chromosomes.

He should get his Y chromosome haplotype sequenced, given the robust genetic variation observed across Y chromosomes.

Answer 31

He should get his mitochondrial haplotype sequenced, given the genetic variation in mitochondrial sequences compared to Y chromosomes.

Question 32

A mutation with a deleterious effect on the function of a protein encoded by a human mitochondrial gene will be:

X-linked.

paternally inherited.

autosomally inherited.

maternally inherited.

Answer 32

maternally inherited.

Question 33

A researcher discovers a new type of plant. After setting up several crosses, she assesses the mitochondrial sequences in the F1 generations and compares these to the mitochondrial sequences in the parental generation. In the progeny, she finds sequences that are similar to both the maternal and paternal sequences in the parental generation. These plants demonstrate _____ inheritance of their organelles.

recombinant

random

paternal

maternal

biparental

Answer 33

biparental

Question 34

A doctor is presented with a patient complaining of persistent muscle weakness. As a side comment, the patient notes that this is something that all of her children also experience, as did her mother when she was alive. This family may be suffering from a mitochondrial disease.

False

True

Answer 34

True