Bio 1200 Chapter 17

When two true-breeding plants that differ in a single character are crossed, the monohybrids display the 1.______ trait, and the 2.______ trait is masked.

1. dominant 2. recessive

Mendel proposed that each individual carries 1.______ 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 2._______ allele(s).

1. two 2. one

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

2 Reason: A person inherits only two alleles: one from each parent.

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

3

The genetic material of a cell is the ____ within chromosomes.

DNA

The genetic material that resides within chromosomes is::

DNA

Match these terms describing alleles with their definitions. Dominant ---> Recessive ---> A. trait is masked B. trait is displayed

Dominant ---> trait is displayed Recessive ---> trait is masked

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

F1 generation.

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

True or false: When multiple alleles of a gene exist, each individual may inherit more than two alleles.

False Reason: Each individual has two alleles of any given gene: one from dad and one from mom. However, sometimes multiple alleles exist in the population, so many different combinations of alleles occur in the population.

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

False Reason: Inheritance is the acquisition of traits by their transmission from parent to offspring, not from offspring to parent.

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

False Reason: Cystic fibrosis is a recessive disorder, so heterozygous carriers do not exhibit any symptoms of the disease.

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

Mendelian inheritance

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

Mendelian inheritance

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

Sex

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

Single-factor cross

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

Match each sex determination system with a representative species. X-Y ----> X-O ----> Z-W ----> haplodiploid ----> environmental ----> A. Alligator B. Bee C. Fruit fly D. Bird E. Human

X-Y ----> E. Human X-O ----> C. Fruit fly Z-W ----> D. Bird haplodiploid ----> B. Bee environmental ----> A. Alligator

Match each sex determination system with the correct factor that determines the sex of an individual. X-Y system ----> X-O system ----> Z-W system ----> haplodiploid system ----> A. haploid or diploid set of chromosomes B. ratio between X chromosomes and autosome sets C. presence or absence of the W chromosome D. presence or absence of the Y chromosome

X-Y system ----> D. presence or absence of the Y chromosome X-O system ----> B. ratio between X chromosomes and autosome sets Z-W system ----> C. presence or absence of the W chromosome haplodiploid system ----> A. haploid or diploid set of chromosomes

Genes found exclusively on the X chromosome are called:

X-linked

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

X-linked genes

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

alleles

The three important ideas Mendel postulated concerning the transmission of traits from parents to offspring include: an individual carries two variants of genes per trait traits exist in three forms - dominant, recessive, and co-dominant an individual carries three variants of genes per trait 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 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

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

chromosomes or chromatids

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

dominant inheritance

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

epitasis

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

genotype

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

genotype

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

genotype

Pedigree analysis is typically used for studying:

human traits that follow simple Mendelian inheritance patterns

The offspring of hybridization experiments are referred to as:

hybrids

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

identical alleles Reason: The alleles on a chromosome and its homologue would be different, but on the sister chromatids of a single duplicated chromosome, the alleles would be the same.

________ dominance involves an intermediate phenotype in the heterozygote

incomplete

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

independent

What is represented in pedigree analysis?

inheritance of an inherited trait over several generations in one family

The acquisition of traits by their transmission from parent to offspring is called:

inheritance or heredity

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

Mendel's laws of inheritance are used in agriculture to develop commercially important: harvesting practices dairy practices livestock crops

livestock crops

The sex chromosomes refer to a distinctive pair of chromosomes that vary between:

male and females

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

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 phenotypic range exhibited by individuals with a particular genotype under differing environmental conditions is called the:`

norm of reaction

Carriers of the cystic fibrosis allele are phenotypically:

normal Reason: Carries of the recessive cystic fibrosis allele are heterozygous and therefore display the dominant phenotype.

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

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

offspring of a hybridization experiment

Sex-linked genes are found on:

one sex chromosome but not the other

Most of Mendel's experiments were conducted using:

pea plants

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

pedigree analysis

______ is the analysis of an inherited trait over several generations in one family.

pedigree analysis

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

probability

_______ square can be used to predict the outcome of a simple genetic cross.

punnett square

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

random

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

Genes found on one sex chromosome but not the other are called:

sex-linked genes

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

single

In meiosis, when a cell prepares to divide, the homologs replicate so that each homolog consists of a pair of:

sister chromatids

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

What is the norm of reaction?

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

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

the variants of only one character.

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

true-breeding

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

two different characters.

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

two-factor cross

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

wild-type Reason: The most common allele in a population is the wild type allele. The terms dominant and recessive refer to the phenotypic manifestation of alleles in combination with one another. The wild type allele could be dominant or recessive to another allele

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

wild-type allele