question

How could the botanist best determine whether the genotype of the green-pod plant is homozygous or heterozygous?

answer

cross the green pod plant with a yellow pod plant

question

Suppose that the botanist carried out the test cross described in Parts A and B and determined that the original green-pod plant was heterozygous (Gg). Which of Mendel's findings does her test cross illustrate?

answer

Law of segregation

question

During which part of meiosis (meiosis I or meiosis II) do the two alleles of a gene separate? During which phase does the separation occur?

answer

Meiosis I, anaphase

question

Gamete possibilities a. 3/4 Y 1/4 y b. 1/2 Y 1/2y c. 1/2 YY 1/2 yy d. 1/2 Yy 1/2 Yy e. 3/4 y 1/4 Y f. 1/2 y 1/2 y

answer

a. incorrect b. correct c. incorrect d. incorrect e. incorrect f. incorrect

question

What is the probability that an F2 seed chosen at random will be yellow?

answer

3/4

question

What is the probability that an F2 seed chosen at random from among the yellow seeds will breed true when selfed?

answer

1/3

question

What is the probability that three F2 seeds chosen at random will include at least one yellow seed?

answer

63/64

question

What is the probability that three F2 seeds chosen at random will include one green seed and two yellow seeds?

answer

27/64

question

What is the difference between heterozygous and homozygous individuals?

answer

All of the gametes from a homozygote carry the same version of the gene while those of a heterozygote will differ.

question

When constructing a Punnett square, the symbols on the outside of the boxes represent____________, while those inside the boxes represent_________.

answer

gametes, progeny

question

True or false? The same phenotype can be produced by more than one genotype.

answer

True

question

True or False? In diploid organisms, a dominant phenotype will only be expressed if the individual is homozygous dominant for that trait.

answer

False

question

If an organism with the genotype AaBb produces gametes, what proportion of the gametes would be Bb?

answer

None

question

Two mice are heterozygous for albinism (Aa) . The dominant allele (A) codes for normal pigmentation, and the recessive allele (a) codes for no pigmentation. What percentage of their offspring would have an albino phenotype?

answer

25

question

A tall, purple-flowered pea plant (TtPp) is allowed to self-pollinate. (The recessive alleles code for short plants and white flowers.) The phenotypic ratio of the resulting offspring is 9:3:3:1. What is the genotype of the plant whose phenotype appeared once out of every 16 offspring (the "1" in the 9:3:3:1 ratio)?

answer

ttpp

question

What process is responsible for the independent assortment of alleles?

answer

meiosis

question

How do cells acquire homologous chromosome pairs that carry the alleles that are independently assorted?

answer

fusion of gametes

question

Which of the following statements most accurately describes the process of independent assortment?

answer

Alleles of different genes segregate from one another in a random manner.

question

True or false? The principle of independent assortment is best illustrated by events that take place during metaphase II, during which sister chromatids segregate independently of each other.

answer

false

question

How many genetically unique types of gametes could be produced by an individual with the genotype RrYY?

answer

two

question

Which of the following parental genotypes would yield a 1:1:1:1 phenotypic ratio in the offspring?

answer

AaBb, aabb

question

The mutent allele is dominant to its corresponding wildtype allele

answer

twist

question

the mutent allele is dominant to its corresponding wildtype allele

answer

forked

question

The mutent allele is neither dominant or completely recessive to its corresponding wild type allele.

answer

pale

question

Which of the following statements best explains the outcome of this cross?

answer

The forked mutation and the twist mutation are codominant alleles of the same locus.

question

What defines a short sleeper?

answer

they can function well on 6 hours or less of sleep

question

While it is estimated that less than 5% of the population are short sleepers,

answer

an estimated 30% of the population sleep only 6 hours per night or less

question

The risks of sleep deprived include

answer

obesity cardiovascular disease memory problems

question

The discovery of a gene associated with short sleepers means that

answer

there is potential to manipulate sleep pathways with medication.

question

Since there is a genetic explanation for short sleepers, you would expect

answer

that this trait appears more frequently among family members.

question

Hemophilia is caused by a sex-linked recessive gene, I am sure I do not have hemophilia, what genotype must I be ?

answer

XHX0

question

Consider the hypothetical sex-linked recessive baldness gene, if a bald woman has a child with a normal male, what are the odds their son will be bald?

answer

100%

question

Consider the following family history: Bob has a genetic condition that affects his skin. Bob's wife, Eleanor, has normal skin. No one in Eleanor's family has ever had the skin condition. Bob and Eleanor have a large family. Of their eleven children, all six of their sons have normal skin, but all five of their daughters have the same skin condition as Bob. Based on Bob and Eleanor's family history, what inheritance pattern does the skin condition most likely follow?

answer

X-linked dominant

question

A homozygous wild-type female fly is mated with a vermilion male fly. Predict the eye colors of F1 and F2 generations.

answer

F1 females : All wild type F1 males : All wild type F2 females : All wild type F2 males : 1/2 wild type, 1/2 vermillion

question

Red-green color blindness is due to an X-linked recessive allele in humans. A widow's peak (a hairline that comes to a peak in the middle of the forehead) is due to an autosomal dominant allele. Consider the following family history: A man with a widow's peak and normal color vision marries a color-blind woman with a straight hairline. The man's father had a straight hairline, as did both of the woman's parents. Use the family history to make predictions about the couple's children.

answer

If the couple has a child, what is the chance that it will be a son with a widows peak ? 1/4 What is the chance that any son the couple has will be color blind with a straight hairline? 1/2 What is the chance that any daughter that the couple has will be color blind with a widows peak? 0 Suppose the couple had a daughter with normal color vision and a widows peak. What is the chance that she is heterozygous for both genes? 1

question

solid, normal, smooth : solid, normal, peach : solid, dwarf, smooth : solid, dwarf, peach : mottled, normal, smooth : mottled, dwarf, smooth : mottled, dwarf, peach :

answer

1:1:1:1:1:1:1:1

question

Now, suppose that the three tomato genes from Part A did not assort independently, but instead were linked to one another on the same chromosome. Would you expect the phenotypic ratio in the offspring to change? If so, how?

answer

All eight possible phenotypes could occur, but a greater proportion of the offspring would have the parental phenotypes.

question

What is a nondisjunction?

answer

An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell

question

When can nondisjunction occur? Choose the best answer.

answer

In meiosis, when homologous chromosomes fail to separate In meiosis, when sister chromatids fail to separate In mitosis, when sister chromatids fail to separate

question

Which syndrome is characterized by the XO chromosome abnormality?

answer

Turner syndrome

question

What kind of cell results when a diploid and a haploid gamete fuse during fertilization?

answer

A triploid cell

question

Of the following chromosomal abnormalities, which type is most likely to be viable in humans?

answer

Trisomy

question

If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n − 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred?

answer

A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell.

question

If a diploid cell undergoes meiosis and produces two gametes with n + 1 chromosomes and two gametes with n− 1 chromosomes, what type of error occurred?

answer

A nondisjunction error occurred in meiosis I, in which both members of a homologous pair migrated to the same pole of the cell.

question

The following table illustrates some structural mutations that involve one or both of these chromosomes. Identify the type of mutation that has led to each result shown. AB-CDEFH I-JNKLMN AB-CLMN I-JKDEFGH AEDC-BFGH AB-CDDCEFGH AB-CDEKLMNFGH IJ I-JMLKN

answer

deletion duplication translocation inversion duplication translocation inversion

question

Meiosis occurs normally (no nondisjunction)

answer

3 only

question

Nondisjunction of one chromosome pair in meiosis I

answer

2 or 4

question

Nondisjunction of all three chromosome pairs in meiosis I

answer

0 or 6

question

Nondisjunction of one chromosome in one daughter cell in meiosis II

answer

2 3 or 4

question

Nondisjunction of all three chromosomes in one daughter cell in meiosis II

answer

0 3 or 6

question

Cystic fibrosis is an inherited disorder that affects which of the following?

answer

heart lungs liver

question

How long can sperm be cryogenically stored and still be viable?

answer

for more than 20 years

question

Which federal agency ensures that sperm donors are tested for communicable diseases?

answer

Food and Drug Administration

question

Which of the following is true?

answer

Both women and men can be carriers for genetic disorders

question

Which of the following is a leading cause of sudden death among young athletes

answer

HCM

question

Helicase

answer

Binds at the replication fork breaks H-bonds between bases

question

Topoisomerase

answer

binds ahead of the replication fork breaks covalent bonds in DNA backbone

question

Single-strand binding protein

answer

binds after the replication fork prevents H-bonds between bases

question

Leading strand

answer

only one primer needed made continuously daughter strand elongates toward replication fork

question

Lagging strand

answer

multiple primers needed made in segments daughter strand elongates away from replication fork

question

both strands

answer

synthesized 5' to 3'

question

Drag the labels to their appropriate locations in the flowchart below, indicating the sequence of events in the production of fragment B

answer

pol III binds to 3' end of primer b -> pol III moves 5' to 3', adding DNA nucleotides to primer B -> pol I binds to 5' end of primer A -> pol I replaces primer A with DNA -> DNA ligase links fragments A and B

question

During DNA replication, the leading strand is synthesized continuously, whereas the lagging strand is synthesized as Okazaki fragments. Why is this so?

answer

DNA synthesis can take place only in the 5' to 3' direction.

question

Who demonstrated that DNA is the genetic material of the T2 phage?

answer

Hershey and Chase

question

The radioactive isotope 32P labels the T2 phage's

answer

DNA

question

Hershey and Chase used ___ to radioactively label the T2 phage's proteins

answer

35 S

question

After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained___, which demonstrated that ___ is the phage's genetic material

answer

labeled DNA... DNA

question

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.

answer

thymine ... cytosine

question

DNA is a self-replicating molecule. What accounts for this important property of DNA?

answer

The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C

question

Short segments of newly synthesized DNA are joined into a continuous strand by _____

answer

ligase

question

After DNA replication is completed, _____.

answer

each new DNA double helix consists of one old DNA strand and one new DNA strand

question

The first step in the replication of DNA is catalyzed by _____.

answer

helicase

question

The action of helicase creates _____.

answer

replication forks and replication bubbles

question

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

answer

DNA polymerase can assemble DNA only in the 5' to 3' direction

question

The synthesis of a new strand begins with the synthesis of a(n) _____.

answer

RNA primer complementary to a preexisting DNA strand

question

An old DNA strand is used as a _____ for the assembly of a new DNA strand.

answer

template

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