Biology Chapter 17

Which blood types can have heterozygous genotypes associated with them?

Blood type AB Blood type A Blood type B

The three important ideas Mendel postulated concerning the transmission of traits from parents to offspring include:

-the two alleles of a gene separate during gamete formation so that each gamete receives a single allele per trait -traits exist in two forms - dominant and recessive -an individual carries two variants of genes per trait

Males inherit their X chromosome from their mother ______ of the time.

100%

Mendel proposed that each individual carries forms of a gene for a given character, which are called alleles, and that the alleles of a gene separate during gamete formation so that each gamete receives allele(s).

2,1

A Punnett square for a single trait should be set up as a ______ square (Not counting the squares for parental gametes).

2x2

The term multiple alleles refers to the presence of ______ or more alleles in the population.

3

In pea plants, when a true-breeding line with axial flowers is crossed with a true-breeding line with terminal flowers, all of the F1 offspring have axial flowers. What phenotypic ratio is expected in the F2 generation?

3 axial: 1 terminal

What is the end result of meiosis?

4 haploid cells

When two P generation individuals are crossed, the offspring constitute the

F1 generation.

True or false: Most traits are influenced by one gene.

False

Particulate inheritance was first proposed by

Gregor mendel

I-2

Heterozygous

II-1

Homozygous dominant

III-4

Homozygous recessive

Which blood type alleles are codominant to each other?

IA and IB

Select the best definition of a character.

A general feature of an organism

X-linked inheritance

A pattern of traits determined by genes that display a dominant/recessive relationship and are located on the x chromosome.

Epistasis

A type of gene interaction where the allele of one gene masks the effects of a dominant allele of another gene.

Which of the following characters is an example of codominance?

ABO blood type

What observation did Mendel make that refuted the notion of blending inheritance?

Monohybrids resembled one of the two parents rather than displaying an intermediate trait.

What explanation of inheritance suggests that hereditary traits are determined by discrete units that are transmitted from one generation to the next?

Particulate inheritance

Which gene plays a critical role in the developmental pathway that leads to maleness in humans?

SRY

What theory states that the inheritance patterns of traits can be explained by the transmission of chromosomes during meiosis and fertilization?

The chromosome theory of inheritance

What rule should be used to calculate the probability that independent events will occur together?

The product rule

What is the purpose of a testcross?

To determine the genotype of an individual with a dominant phenotype

IAi

Type A

Mendel postulated that every individual carries two genes for a given character. Furthermore, the gene for each character in his pea plant exists in two variant forms, and these forms are now called .

alleles

Mendel's laws of inheritance are used in family planning to uncover in parents that may cause inherited disease in possible offspring.

alleles

Mendel used the garden pea to study inheritance because the pea plants were:

available in many varieties

haplodiploid

bee bee

Z-W

bird bird

The combination of alleles that an individual has for a particular gene is the individual's:

genotype

The combination of alleles that an individual possesses, such as Tt or TT, is the individual's .

genotype

The term describes the genetic composition of an individual for a particular gene.

genotype

heterozygous

half shaded

Meiosis results in the production of four daughter cells that each carry a single copy of one of the two original homologs.

haploid

haplodiploid system

haploid or diploid set of chromosomes

An individual with two identical alleles of a gene of a particular trait has a(n) genotype with respect to that gene.

homozygous

In a pedigree, a female and a male who mate are connected by a(n) ______ line.

horizontal

X-Y

human human

Pedigree analysis is typically used for studying:

human traits that follow simple Mendelian inheritance patterns

What type of experiment involves mating two individuals with different characteristics to each other? One individual provides females gametes, while the other provides male gametes.

hybridization

The offspring of hybridization experiments are referred to as

hybrids

The appropriate time to use the product rule is when dealing with events that are:

independent

In an incomplete dominance pattern of inheritance, a heterozygous individual shows a(n) ______ phenotype.

intermediate

The results of pedigree analysis are less definitive than breeding experiments because the small size of human families results in:

large sampling errors

It is ______ common to find Y-linked genes as compared to X-linked genes.

less

When two genes are located close to one another on a chromosome, they tend to be transmitted together. This phenomenon is known as .

linkage

Which phenomenon describes the presence of two genes very close to each other on the same chromosome, and which are transmitted together as a unit?

linkage

In a Punnett square, the symbols that make up the headings for the columns and rows correspond to the:

male and female gametes

In a recessive pattern of inheritance, two unaffected parents:

may produce affected or unaffected offspring

Consider two true-breeding individuals that differ in a single character. If these mate, their offspring are

monohybrids

The offspring of two true-breeding parents that differ in a single character are called single-trait hybrids, or

monohybrids

Most, or perhaps all, traits are influenced by ______ gene(s).

multiple

Carriers of the cystic fibrosis allele are phenotypically:

normal

Mendel's work involved quantitative experiments and careful analysis of the ______ of offspring carrying specific traits.

number

In genetic crosses, the term "hybrid" refers to:

offspring of a hybridization experiment

According to Mendel's law of segregation, the alleles of a gene segregate during gamete formation so that each gamete receives

one allele

Sex-linked genes are found on:

one sex chromosome but not the other

The concept of inheritance suggested that the determinants of hereditary traits are transmitted in discrete units from one generation to the next.

particulate

What type of plant did Mendel use for most of his work?

pea

In pea plants, the allele T codes for tall plants and the allele t codes for short plants. If a plant is short, this would be considered its

phenotype

Continuous phenotypic variation in quantitative traits is due to the combined effects of:

polygenic inheritance and environment

The ______ alignment of chromosomes in meiosis I leads to the independent assortment of alleles on different chromosomes.

random

Two unaffected parents produce an affected child. This is a characteristic of a(n) pattern of inheritance.

recessive

What pattern of inheritance is suspected when two unaffected individuals produce affected offspring?

recessive

In pea plants, a female gamete is normally fertilized by a male gamete from the same plant. This process is called -fertilization.

self

What aspect of chromosome behavior during meiosis explains Mendel's law of segregation?

separation of homologous chromosomes during meiosis I

The chromosomes are a pair of chromosomes that are different in males and females.

sex

When a cell prepares to divide, the homologs replicate so that each homolog consists of a pair of chromatids.

sister

males

square

What is the norm of reaction?

the phenotypic range displayed by individuals with a particular genotype under different environmental conditions

A two-factor cross is one in which an experimenter follows the inheritance of

two different characters.

Each parent carries alleles of a gene that will segregate from each other during gamete formation.

2

If a particular gene in a population has multiple alleles, how many alleles of that gene will a diploid individual possess?

2

The theory of inheritance states that inheritance patterns of traits can be explained by the transmission of chromosomes during meiosis and fertilization.

chromosome

Independent assortment of alleles of different genes can be explained by the random alignment of homologous pairs of during meiosis I.

chromosomes

females

circles

A situation where a single individual expresses two different alleles is referred to as

codominance

The phenomenon in which an individual expresses two different alleles of the same gene (as in blood type AB) is called .

codominance

The ABO system is an example of which of the following?

codominance multiple alleles

Traits such as blood type in humans, white or purple flowers in sweet pea plants, and curly or normal wings in fruit flies are examples of traits, because the phenotypes do not overlap.

discrete

Traits with clearly defined phenotypic variants that can be sorted into distinct categories are known as traits.

discrete

When two true-breeding plants that differ in a single character are crossed, the monohybrids display the trait, and the trait is masked.

dominant recessive

Traits that appear in every generation and affect males and females exhibit:

dominant inheritance

Quantitative traits show a continuous range of phenotypes and often are influenced not only by multiple genes but also by the .

environment

The pattern of inheritance in which the expression of one gene masks the expression of another gene is known as .

epistasis

True or false: Heterozygous carriers of the CFTR allele exhibit the symptoms of cystic fibrosis.

f

True or false: In all animals that have a Y chromosome, the presence of the Y chromosome results in male development.

false

True or false: Inheritance is the acquisition of traits by their transmission from offspring to parent.

false

affected

filled in

Siblings in a pedigree are notated in the order of their birth:

from left to right

X-O

fruit fly

The unit of heredity is the

gene

What is broadly defined as a unit of heredity?

gene

Mendel proposed that a unit factor, now called a , codes for a character, and each individual carries two variant forms, now called , of the unit factor for a given character.

gene, alleles

Mendel's "unit factors" that are passed intact from one generation to the next are now called

genes

What is the modern term for Mendel's "unit factors" that are passed on intact from one generation to the next?

genes

Which of the following are examples of quantitative traits in humans?

height metabolic rate skin color

Consider a testcross where the unknown parent is heterozygous. The offspring will be

heterozygotes and homozygotes

After DNA replication in a heterozygote, the two sister chromatids on a single chromosome contain:

identical alleles

dominance involves an intermediate phenotype in the heterozygote

incomplete

What is represented in pedigree analysis?

inheritance of an inherited trait over several generations in one family

A gene found on the X chromosome and not on the y chromosome is designated as an X- gene.

linked

Mendel's laws of inheritance are used in agriculture to develop commercially important

livestock crops

The of a gene is its physical location on a chromosome.

locus

The sex chromosomes refer to a distinctive pair of chromosomes that vary between and individuals.

male and female

Recessive X-linked alleles affect

males more than females.

The term refers to the presence of three or more alleles in the population.

multiple alleles

Normal alleles become abnormal alleles through the process of

mutation

The difference between a normal allele and one that causes disease is the result of

mutations

The phenotypic range exhibited by individuals with a particular genotype under differing environmental conditions is called the of .

norm of reaction

The formula for a probability that a random event will have a specific outcome is equal to the number of times an event occurs divided by the:

number of possible outcomes

A(n) analysis is the analysis of an inherited trait over several generations in one family.

pedigree

Human traits that follow simple Mendelian patterns are usually studied using:

pedigree analysis

A cross that follows the simultaneous inheritance of two different characters is called a(n) -cross.

two factor

An individual who is homozygous for a given gene carries:

two identical alleles of the gene

A hybridization experiment involves mating:

two individuals of the same species with different characteristics

unaffected

unshaded

For any given gene, the prevalent allele in a population is known as the - allele.

wild type

What type of allele is defined as the prevalent allele in a population?

wild-type

Place the steps of the Punnett square approach in the correct order. Start with the first step at the top.

write down genotypes write down possible fill in determine

In humans, the term sex-linked genes usually refers to -linked genes.

x

Mendel chose to study characters of pea plants that occurred in:

two discrete variants

Select all of the following that are principles of the chromosome theory of inheritance.

-Genes are found in the chromosomes. -The nucleus of a diploid cell contains homologous pairs of chromosomes. -Chromosomes are replicated and passed from parent to offspring and from cell to cell. -During meiosis, the homologous pairs segregate independently and haploid gametes are produced. -Gametes are haploid cells that combine to form a diploid cell during fertilization.

Which of the following complex inheritance patterns are correctly matched to their description?

-Simple Mendelian: Pattern determined by alleles pair displaying dominant/recessive relationship located on autosome. -Epistasis: The alleles of one gene mask the effect of the alleles of another gene.

In pea plants, purple flowers are dominant to white flowers. If a heterozygous plant with purple flowers is testcrossed to a white plant, what phenotypic ratio will be observed in the offspring?

1/2 purple flowers and 1/2 white flowers

What does Mendel's law of segregation state?

Alleles of a gene segregate during gamete formation so that half the gametes receive one allele and half receive the second allele.

In pea plants, purple flowers are dominant to white flowers, and axial flowers are dominant to terminal flowers. If a true-breeding plant with purple, axial flowers is crossed with a true-breeding plant with white, terminal flowers, what proportion of the F2 offspring will have purple, terminal flowers?

3/16

In pea plants, purple flowers are dominant to white flowers, and the purple and white alleles are represented with P and p, respectively. In a cross between two heterozygotes, what proportion of the offspring are expected to be purple?

3/4

A true-breeding pea plant with smooth green pods is crossed with a true-breeding plant with constricted yellow pods. The F1 offspring all have smooth green pods. If these F1 individuals are cross-fertilized, what proportion of the F2 offspring are expected to have smooth green pods?

9/16

What ratio is obtained in the F2 generation of a dihybrid cross when alleles assort independently from one another?

9:3:3:1

continuous variation

An inheritance pattern produced by the additive interactions of several genes, along with environmental effects.

Codominance

An inheritance pattern that occurs when the heterozygote expresses both alleles simultaneously.

Which of the following properties of the garden pea were advantageous for Mendel's studies of inheritance?

Availability of many varieties with different traits Capacity for self-fertilization or cross-fertilization Ease of making crosses

The genetic material of a cell is the within chromosomes.

DNA

Plants from two different true-breeding P generation lines are crossed to one another and produce offspring. These offspring are allowed to self-fertilize, which results in production of the:

F2 generation

The pattern of inheritance that deals with genes that segregate and assort independently is described by the term inheritance.

Mendelian

What type of inheritance involves genes that segregate and assort independently?

Mendelian inheritance

Who hypothesized that traits could be modified by physiological events and that those modifications could be inherited by offspring?

Lamarck

In the late 1700s, the French naturalist hypothesized that traits could be modified by physiological events and that those modifications could be inherited by offspring.

Lamark

Which of Mendel's laws states that alleles of different genes assort independently of each other during gamete formation?

Law of independent assortment

Who was the researcher who suggested particulate inheritance in the 1860s?

Mendel

Which of these is commonly used to predict the results of simple genetic crosses?

Punnett square

Flower color is an example of a(n) in pea plants. Purple and white flower colors are examples of .

character trait

IAIB

Type AB

IBIB

Type B

ii

Type O

The concept of inheritance proposes that both parents make equal genetic contributions to their children and that their genetic material blends together.

blending

The explanation of inheritance which suggested that parents make equal contributions to their offspring and that their genetic material joins together is called:

blending inheritance

A general feature of an organism, such as plant height or flower color, is called a(n) ______.

character

Genes found exclusively on the X chromosome are called:

X-linked

In the X-O sex determination system, which of the following genotypes could be found in a female? Select all that apply.

XX XXY

The sex chromosome makeup of a human female is and the sex chromosome makeup of a male is .

XX and XY

In what system does the Y chromosome determine maleness?

XY

In the X-O system, which operates in many insects, females are XX and males are either:

XY X

The SRY gene on the chromosome is associated with the developmental pathway that leads to maleness.

Y

The chromosome determines maleness in mammals.

Y

Which chromosome causes maleness in mammals?

Y

Pea plants are self fertilizing which means that a female gamete is fertilized by:

a male gamete from the same plant

In a pedigree, parents are connected to their offspring by:

a vertical line

The law of independent assortment states that:

alleles of different genes assort independently during gamete formation

environmental

alligator alligator

In recessive inheritance, two affected parents will:

always produce affected offspring

In Mendel's experiments, the monohybrids resembled one of the two parents rather than displaying an intermediate trait. This observation refuted the notion of inheritance that was popular at the time.

blending

Z-W system

presence or absence of the W chromosome

X-Y system

presence or absence of the Y chromosome

The chance that an event will have a particular outcome is called

probability

Traits that show continuous variation over a range of phenotypes are known as ______ traits.

quantitative

Mendel's proposed his laws of inheritance based on:

quantitative experiments

X-O system

ratio between X chromosomes and autosome sets

A trait that causes a disease will occur more frequently in males than females if the trait is

recessive and X-linked

That two unaffected individuals can produce an affected offspring exhibits:

recessive inheritance

The limitations of pedigree analysis as compared to breeding experiments include:

sample size too small

Mendel's law of is the idea that the two alleles of a gene separate during the formation of eggs and sperm so that every gamete receives only one allele.

segregation

Mendel's focus on ________ genes was pivotal in establishing the science of genetics because it allow Mendel to formulate basic laws of inheritance.

single

A cross in which only one character is studied is called a(n) - cross.

single factor

An individual with a dominant phenotype may be either homozygous or heterozygous. To determine the exact genotype of this individual a method called a(n) can be used.

testcross

Epistasis is the pattern of inheritance in which:

the alleles of one gene mask the expression of the alleles of another gene

According to the chromosome theory of inheritance, Mendel's laws can be explained by:

the behavior of chromosomes during meiosis the effect of the environment on gene expression

The separation of homologous chromosomes during meiosis I explains:

the law of segregation

If a true-breeding line is allowed to self-fertilize for several generations, the resulting offspring will have:

the same traits as the parents

A single-factor cross is one in which an experimenter follows

the variants of only one character.

A variant form of a character is called a(n) .

trait

True or false: Each character that Mendel selected to study was found in two discrete variants.

true

True or false: In humans, both males and females receive an X chromosome from their mothers.

true

The critical element of Mendel's research focus was to use __________ strains that differed with regard to only one gene.

true-breeding