BSC Smartbook Chapter 10

Select all of the following that are true of Marfan syndrome.

- caused by a dominant allele - pleiotropic gene expression - many symptoms, such as weak aorta, lens dislocation, long limbs

Select all of the following that are true about linked genes.

- do not assort independently - located on the same chromosome - inherited together

Match each genotype in human blood typing with its correct phenotype.

- genotype I^Ai or I^AI^A matches: type A blood - genotype I^Bi or I^BI^B: type B blood - genotype I^AI^B: type AB blood - genotype ii: type O blood

Select all of the advantages of studying heredity with the pea plant Pisum sativum over another species.

- produces many offspring. - can self-fertilize - develops quickly - can cross-fertilize - many traits with two distinguishable forms

Select all of the following that are human gametes.

- sperm - eggs

A diploid cell has ______ alleles for each gene, one on each homologous chromosome.

2

If a gene exists in 10 different alleles in a population, how many alleles can be expressed in one diploid cell?

2

In the monohybrid cross between yellow-seeded F1 plants (Yy x Yy) shown in the image, about what percent of the F2 generation will show the recessive phenotype of green seeds?

25%

When Mendel mated two F1 generation yellow-seeded (Yy) pea plants, what was the phenotypic ratio in the F2 offspring? (Green-seeded pea plants are genotype yy.)

3 yellow seeds: 1 green seed

Which of the following is a genotype?

Aa

Match the position on a monohybrid Punnett square with its correct description.

Above and left Punnet Square - possible alleles of haploid and egg Inside Punnet square - possible allele combinations of diploid offspring

What is a consequence of multiple proteins being involved in one biochemical pathway?

An altered phenotype can be due to mutations in different possible genes.

The genotype of a heterozygous individual is ______, of a homozygous dominant is ______, and of a homozygous recessive individual is ______.

Gg; GG; gg

Who discovered how to calculate probabilities of inheritance primarily using traits of pea plants?

Gregor Mendel

In Mendel's experiments, the hybrid plants had what genotype?

Heterozygous

Select all of the possible genotypes for the true-breeding plants in Mendel's experiments.

Homozygous dominant; homozygous recessive

Which of the following genotypes is heterozygous?

Yy

Which of the following represents a monohybrid cross?

Yy x Yy

Alternative forms of a gene are called

alleles

Different varieties of the same gene, called ______, may arise from mutations.

alleles

In the cookbook analogy of chromosomes, ______ are like the variable options for a particular recipe, which represents a gene.

alleles

Of the 23 pairs of human chromosomes, the 22 pairs of chromosomes that are the same in both sexes and are not sex chromosomes are called the ________.

autosomes

When one gene's products affect the expression of another gene, this is called

epistasis.

The haploid cells of humans are called

gametes

If a chromosome is like a cookbook, then a recipe in the cookbook is like a ______, which contains the information to synthesize a protein.

gene

Referring to this linkage map image, what pair of genes has the highest crossover frequency?

genes V and W

Based on the image, what pair of genes exhibits the lowest crossover frequency?

genes W and Y

An individual's allele combination for a particular gene is called the ____.

genotype

A cell with one set of chromosomes is a(n) ______ cell.

haploid

Gametes, or sex cells, are ________, meaning they contain only one set of chromosomes.

haploid

A(n) ______ individual has 2 different alleles for a given gene.

heterozygous

A ______ individual has two identical alleles for a gene.

homozygous

The bottom panel of the picture shows the offspring genotypes that resulted from Morgan's cross between a male fruit fly heterozygous for two genes (AaBb) and a female fruit fly that was homozygous recessive for the same two genes (aabb). What accounts for the 5:1:1:5 genotypic ratio in the offspring that differs from the ratio Mendel would have predicted?

linked genes

Homologous chromosomes contain the same genes but may contain different alleles at a particular site, called a gene

locus

The physical location of a gene on a chromosome is called the gene's .

locus

After Mendel's work, biologists determined that a single chromosome carries

many genes

A _______ cross is a mating between two individuals that are both heterozygous for the same, single gene.

monohybrid

An example of a(n) ______ cross is the mating of two rats that both contain the alleles Ff for fur color. This cross is made to examine which of two fur colors their offspring will have.

monohybrid

Linkage groups are sets of genes transmitted

on the same chromosome

If two genes are located close together on the same chromosome, offspring are likely to inherit ______ chromatids, which have the same allele combinations present in the parents.

parental

After meiosis II, what type of genetic material retains the allele combination present in the parents?

parental chromatids

In a genetic cross, what does the P generation represent?

parental generation

An individual's is its observable characteristics for a particular trait.

phenotype

What are the observable characteristics of an individual's genes?

phenotype

The ________ rule states that the chance of two independent events occurring is equal to the product of the individual chances that each event will occur.

product

If a couple that are both heterozygous carriers of the cystic fibrosis allele have children, the chance that both their first and their second child are carriers is 0.5 x 0.5, or 25%, as determined by the

product rule

A ______ is a diagram that shows how the parental alleles may combine to form possible genotypes of the offspring.

punnet square

If the genotype for a trait is Tt, the t allele is called the _________ allele, whose effect is masked by the other allele.

recessive

The trait encoded by a ______ allele will only be exhibited if two copies of the allele are present in the genotype.

recessive

What type of trait in Mendel's studies could vanish in one generation and reappear in the next generation?

recessive

Although Mendel did not know that homologous chromosomes separate during meiosis I such that the alleles of one gene are packaged into separate gametes, he developed the law of ______, which deduced this phenomenon.

segregation

One of the reasons that Mendel was able to discover the basic principles of genetics using pea plants is because pea plants

self-fertilize and cross-fertilize.

In the human genome, the X and Y chromosomes are called the

sex chromosomes

Red-green color blindness and hemophilia are examples of ______, which are controlled by alleles on the sex chromosomes.

sex-linked genes

A gene is

stretch of DNA nucleotides that encodes a protein.

In a ________ cross, an individual with an unknown genotype is mated with an individual with a homozygous recessive genotype to determine the unknown genotype.

test

To determine if the genotype of a pea plant with a dominant phenotype is homozygous dominant or heterozygous, a ______ may be completed.

test cross

When Morgan crossed a male fruit fly that was heterozygous for two genes (AaBb) with a female fruit fly that was homozygous recessive for the same two genes (aabb), most of the offspring were either homozygous recessive or heterozygous for both genes, indicating that

the genes for these traits are linked

A ______ organism always produces offspring that are identical to the parent when self-fertilized.

true-breeding

A diploid cell contains

two full sets of chromosomes.

In a population of fruit flies, most flies have two antennae; based on this information, the phenotype of two antennae is definitely a ______ phenotype.

wild-type

The most common allele of a gene in a population of fruit flies is called the ______ allele.

wild-type

What describes the basis of gene linkage maps, as proposed by Sturtevant in 1911?

The farther apart two genes are, the more likely crossing over is to separate them.

Select the true statement about genes and chromosomes.

The number of genes in a cell exceeds the number of chromosomes.

Mendel mated a pea plant of true-breeding round, yellow seeds (RR YY) with a pea plant of true-breeding wrinkled, green seeds (rr yy). A Punnett square analysis shows that _______ % of the F1 generation has round, yellow seeds.

100

In a cross between two traits, Mendel mated a pea plant of true-breeding round, yellow seeds (RR YY) with a pea plant of true-breeding wrinkled green seeds (rr yy). What is the genotypic ratio of the F1 generation?

100% Rr Yy

The first filial generation in a genetic cross is written as the ______ generation.

F1

The offspring of the first set of individuals mated in a particular cross is the

F1 generation

True or false: For some of the traits Mendel studied, alleles were incompletely dominant or codominant.

False

This diagram of gamete production from meiosis and gamete fusion in fertilization supports Mendel's

Law of segregation

______ discovered the principles of genetics before DNA, genes, and chromosomes were discovered.

Mendel

What type of gene expression was present in the seven traits Mendel studied?

One allele was completely dominant over the other.

What is the first set of individuals mated in a particular cross?

P generation

In _______, one gene encodes a protein that is important in many biochemical pathways or that affects many parts of the body.

Pleiotropy

Select all of the following genotypes that are homozygous.

RR; rr

In the nucleus of eukaryotic cells, all of the DNA is divided into multiple _________, which are continuous, long strands of DNA wrapped around proteins.

chromosomes

Homologous chromosomes are

chromosomes that look alike and have the same sequence of genes but may not carry the same alleles.

In a type of gene expression called ______, two different alleles are both expressed fully in the phenotype of the offspring.

codominance

The picture shows human ABO blood types. AB blood type is an example of

codominance

Two different alleles of a heterozygous genotype are both fully expressed to produce the phenotype in a type of expression called

codominance

Alfred Sturtevant proposed that the farther apart two alleles are located on the same chromosome, the more likely ______ is to separate them.

crossing over

What process, depicted in the picture, produces nonidentical chromatids and can interrupt linkage between two genes?

crossing over

The exchange of genetic material between homologous chromosomes during prophase I of meiosis is called ______ and can explain the appearance of ______ in the offspring.

crossing over; recombinant traits

To construct linkage maps, scientists estimate the distance between genes on the same chromosome based on the ______, as indicated by the percentage of recombinant offspring.

crossover frequency

An example of a(n) ______ cross is the mating of two rats that both have the genotype Ff Tt for fur color and tail length to examine which of two fur colors and tail lengths their offspring will have.

dihybrid

What type of cross is a mating between two individuals that are both heterozygous for the same two genes?

dihybrid

A cell with two complete sets of chromosomes is a _______ cell.

diploid

A human ______ cell has 46 chromosomes, 23 chromosomes from each parent.

diploid

A(n) ________ allele always exerts its effects when present.

dominant

In Mendel's studies, a ______ trait is one that could mask the appearance of another trait.

dominant

When one or both copies of a gene are the ______ allele, then this allele's form of the trait will be exhibited.

dominant

Genes that are located on the same chromosome and inherited together are called _______ genes.

linked

What type of plant undergoes self-fertilization to produce some offspring that are identical to the parent and some that are different?

hybrid

In a game expression pattern called __________ dominance, the heterozygote has an intermediate phenotype between the homozygotes.

incomplete

The pink snapdragon flowers in the picture are an example of

incomplete dominance

Mendel deduced the law of ________ ________, which states that alleles for one gene are randomly separated into gametes in a way that is not influenced by the separation of alleles of another gene.

independent assortment

Mendel's _________ states that the segregation of alleles for one gene does not influence the segregation of alleles for another gene during gamete formation.

law of independent assortment

Mendel deduced the law of ________, which states alleles of a gene move apart from each other during gamete formation.

law of segregation

Using the frequency of crossing between genes V and W, what can be created, as shown in the picture?

linkage map