Ch 15

Question 1

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

Answer 1

inheritance

Question 2

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

Answer 2

easy to cross

Question 3

A variant form of a character is called a(n) ______, and a variant form of a gene is called a(n) ______.

Answer 3

trait; allele

Question 4

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

Answer 4

the same traits as the parents

Question 5

The offspring of hybridization experiments are referred to as

Answer 5

hybrids.

Question 6

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

Answer 6

False

Question 7

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:

Answer 7

F2 generation

Question 8

Which of the following properties of the garden pea were advantageous for Mendel’s studies of inheritanc

Answer 8

True-breeding strains were available.
Many varieties with different traits were available.
Pea plants can be self-fertilized or cross-fertilized.

Question 9

Character

Answer 9

A general feature of an organism

Question 10

Trait

Answer 10

A specific variant of a feature of an organism

Question 11

Gene

Answer 11

A genetic determinant that is passed intact from one generation to the next

Question 12

Allele

Answer 12

A variant form of a genetic determinant

Question 13

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

Answer 13

the variants of only one character.

Question 14

True or false: After several generations of self-fertilization of a true-breeding line, all of the offspring will have the same traits as the original parents.

Answer 14

true

Question 15

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

Answer 15

monohybrids

Question 16

In genetic crosses, the term “hybrid” refers to:

Answer 16

offspring of a hybridization experiment

Question 17

What ratio did Mendel observe in the F2 offspring in monohybrid crosses between true-breeding lines for dominant and recessive traits?

Answer 17

3 dominant : 1 recessive

Question 18

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

Answer 18

F1 generation.

Question 19

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.

Answer 19

gene/ allels

Question 20

dominant

Answer 20

trait is displayed

Question 21

recessive

Answer 21

trait is masked

Question 22

A cross in which only one character is studied is called a___ ____

Answer 22

single factor gene

Question 23

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.

Answer 23

segregation

Question 24

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

Answer 24

Monohybrids

Question 25

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

Answer 25

phenotype

Question 26

In Mendel's experiments, he observed a 3:1 ratio between dominant and recessive traits in

Answer 26

the F2 generation of monohybrid crosses.

Question 27

In pea plants, yellow seeds are dominant to green seeds, and the yellow and green alleles are represented with Y and y, respectively. Match each genotype with the correct description of alleles.

Answer 27

YY = Homozygous for the yellow allele Yy = Heterozygous for the yellow and green alleles yy = Homozygous for the Green allele

Question 28

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

Answer 28

Dominant/ recessive

Question 29

In the Punnett square shown here, what information belongs in the box that is circled?

Answer 29

Genotype Tt

Question 30

Mendel's "unit factors" are now called _______________, and their variant forms are referred to as ________________.

Answer 30

genes / alleles

Question 31

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

Answer 31

9:3:3:1

Question 32

What does Mendel's law of segregation state?

Answer 32

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

Question 33

The law of independent assortment states that:

Answer 33

alleles of different genes assort independently during gamete formation

Question 34

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

Answer 34

genotype

Question 35

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

Answer 35

the behavior of chromosomes during meiosis

Question 36

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

Answer 36

2 x 2

Question 37

The separation of homologous chromosomes during meiosis I explains:

Answer 37

the law of segregation

Question 38

A 9:3:3:1 ratio is obtained in the F2 generation of a dihybrid cross when alleles assort _____ from one another

Answer 38

independently

Question 39

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

Answer 39

random

Question 40

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

Answer 40

Law of independent assortment

Question 41

Pedigree analysis is typically used for studying:

Answer 41

human traits that follow simple inheritance patterns

Question 42

Which of the following are principles of the chromosome theory of inheritance?

Answer 42

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

Question 43

Traits that appear in every generation and affect males and females equally are characteristic of:

Answer 43

dominant inheritance

Question 44

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

Answer 44

Separation of homologous chromosomes during meiosis I

Question 45

In a recessive pattern of inheritance, two unaffected parents:

Answer 45

may produce affected or unaffected offspring

Question 46

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

Answer 46

chromosomes

Question 47

True or false: In dominant inheritance, affected parents always have affected offspring.

Answer 47

False

Question 48

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

Answer 48

pedigree analysis

Question 49

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

Answer 49

mendelian

Question 50

Some heterozygotes up-regulate expression of the dominant allele to compensate for the lack of function in a ___ allele.

Answer 50

recessive

Question 51

A trait that appears to skip generations and is present at an equal frequency in males and females exhibits:

Answer 51

recessive inheritance

Question 52

Pleiotropy occurs because

Answer 52

- the expression of a single gene can affect cell function in more than one way - a gene may be expressed in different cell types in a multicellular organism - a gene may be expressed at different stages of development

Question 53

In recessive inheritance, two affected parents will:

Answer 53

always produce affected offspring

Question 54

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

Answer 54

intermediate

Question 55

Individuals with a dominant disorder usually have:

Answer 55

one affected parent

Question 56

In incomplete dominance, a cross of two heterozygotes produces ______ in the offspring.

Answer 56

three distinct phenotypes

Question 57

What type of inheritance involves genes that undergo segregation and independent assortment?

Answer 57

Mendelian inheritance

Question 58

In a simple dominant/recessive relationship, the production of approximately ______ of the protein needed in the heterozygote is plenty for the individual to function typically.

Answer 58

50%

Question 59

How do scientists evaluate the norm of reaction?

Answer 59

By exposing individuals with the same genotype to different environmental conditions

Question 60

_______ is a phenomenon that occurs because a single gene can be expressed in multiple cell types or at several stages of development.

Answer 60

pleiotropy

Question 61

Five sex determination systems are presented here. Match each with its representative species.

Answer 61

``` X-Y ------ humans X-O ----- fruit fly Z-W ----- bird haplodiploid ---- bee environmental --- alligator ```

Question 62

________ dominance involves an intermediate phenotype in the heterozygote.

Answer 62

incomplete

Question 63

If a cross between heterozygotes for a single trait results in three distinct phenotypes, which of the following types of inheritance is the likely reason?

Answer 63

Incomplete dominance

Question 64

Which chromosome causes maleness in mammals?

Answer 64

Y

Question 65

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

Answer 65

Mendelian

Question 66

Genes found on one sex chromosome but not the other are called ______ - _______ genes.

Answer 66

sex linked

Question 67

True or false: To study the norm of reaction, scientists subject individuals with the same genotypes to different environmental conditions.

Answer 67

True

Question 68

Recessive X-linked alleles affect

Answer 68

Recessive X-linked alleles affect

Question 69

Match each sex determination system with the correct factor that determines the sex of an individual

Answer 69

X-Y system ----- presence or absence of the Y chromosome X-O system ---- ratio between X chromosomes and autosome sets haplodiploid system --- haploid or diploid set of chromosomes Z-W system ----- presence or absence of the W chromosome

Question 70

In humans, a male always receives an X chromosome from his ______ and a Y chromosome from his _______

Answer 70

mom and dad