chapter 12

Consider a diploid cell that contains genes Y, R, and Z on separate chromosomes. How many gamete genotypes are possible if a Yy RR Zz cell undergoes meiosis?

4

How many potential phenotypes can result from a dihybrid cross when the traits assort independently from one another?

4

The expected frequency of F₁ plants with yellow pods is ______.

50%

The genotype of the gametes produced by the heterozygous plant is ______.

50% A and 50% a

The genotype of the gametes produced by the woman is _____

50% dB and 50% db.

Type _____ is the universal blood donor and type _____ is the universal blood recipient.

O, AB

When genes lie near each other on the same chromosome, they do not follow Mendel's Law of Independent Assortment. What would you predict about the inheritance of two such genes?

Offspring will inherit the same two alleles that were passed down together from a grandparent.

Juvenile glaucoma is a hereditary disease that causes blindness due to the degeneration of nerves in which of the following?

Optic nerve

In terms of probabilities, the cross of a tall yellow seeded pea plant (TTYy) with a tall green seeded pea plant (Ttyy) is equivalent to which two monohybrid crosses?

TT x Tt and Yy x yy

How can two pea plants be cross-fertilized?

The male parts of flowers on one plants are removed and pollen from the other plant is introduced.

When two consecutive events occur, each one with its own probability (that does not depend on the the probability of the other event), we say that the two events are

independent

This analysis is appropriate for studying traits, such as genetic diseases, that follow simple Mendelian patterns:

pedegree

An allele that has more than one effect on phenotype is called

pleiotropic

Sickle cell anemia is caused by a _____ allele because this mutation has more than one effect on the phenotype.

pleiotropic

The mutation that causes cystic fibrosis affects several traits and is, therefore, an example of a(n)

pleiotropic mutation

Human height is an example of a trait that has a continuous distribution of phenotypes. Human height is therefore an example of ________ inheritance.

polygenetic

Quantitative traits are usually

polygenic

Continuous phenotypic variation results from

polygenic inheritance and independent segregation of genes

To calculate the probability that if a woman has four children, they will all be girls, you should use the

product rule

A(n) ______ square can be used to predict the outcome of a simple genetic cross.

punnet

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

punnet square

Traits that exhibit continuous variation are also called

quantitative traits

Which of the following is NOT a component of Mendel's five-element model (please note that the answers use the modern term gene instead of factor)?

the two alleles are usually the same

A pea plant with green seeds is allowed to self hybridize. All of the resulting offspring plants produce green seeds as well. That plant is therefore considered to be a

true-breeding plant

One of the traits that Mendel studied in pea plant is plant height. Tall plants are dominant with respect to dwarf plants. If the gene for this trait is denoted by the letter "T", then the genotype of a dwarf pea plant is _____

tt

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

two

A hybridization experiment involves mating

two individuals with different characteristics

The probability of genotypes in an independently assorted dihybrid cross is based on the probabilities of

two monohybrid crosses

four blood phenotypes with the sugar exhibited on red blood cells:

type A->galactosamine type B->galactose type AB->have both galactosamine and galactose type O-> have neither sugar

In order to carry out the testcross, you should cross your original pea plant with another pea plant whose phenotype is _____.

white flowers and short stems

People with type AB blood have

both type A and type B antigens on their red blood cells.

Which of the following plants was the main organism for Mendel's genetic experiments?

pea

What was the ratio that Mendel observed between dominant and recessive traits in the F2 offspring of a monohybrid cross?

3 dominant:1 recessive

The genotype of the gametes produced by the man is ______.

25% DB, 25% Db, 25% dB, 25% db

The seven traits that Mendel studied in pea plants have a relatively simple pattern of inheritance. Since the time of Mendel, however, scientists have discovered many traits that have more complex patterns of inheritance. Which of the following elements from Mendel's model of inheritance turned out to be oversimplifications that aren't true for many traits? Check all statements that are oversimplifications.

-Each trait in an organism is controlled by one pair of alleles. -At each gene locus there are two possible alleles, one that is dominant and one that is recessive. -Each pair of alleles controls one trait.

Mendel succeeded in discovering the basic laws of inheritance while many people before him had failed. Which of the following contributed to his success?

-He simplified the problem by looking at only one or two traits at a time -He focused on traits that existed in two easily distinguishable forms -He chose an organism where many pure varieties were available -He chose an organism that was easy to grow and that had a short generation time -He chose an organism where he could easily control whether self-fertilization or cross-fertilization took place -He chose an organism that had a few large chromosomes rather than many small chromosomes

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

2x2

Genes H, T, and Q lie close to each other on the same chromosome, so that independent assortment does not occur. A mother has alleles H T Q on one chromosome and alleles h t q on the other chromosome. The father is homozygous for h t q. What are possible offspring genotype(s)?

-Hh Tt Qq -hh tt Qt

Which of these are not reasons that Mendel chose to study the garden pea:

-Long generation time -They were inexpensive to buy

Which of these traits exhibit a dominant mode of inheritance?

-Mid-digital hair -Hypercholesterolemia -Polydactyly

Choose statements that correctly refer to components of Mendel's five-element model (please note that the answers use the modern term gene instead of factor).

-Parents transmit genes to offspring. -The presence of an allele doesn't ensure that it will be expressed. -The two alleles remain discrete. -Alternative forms of genes are called alleles.

A parent with a genotype of RrYy can produce which of the following gametes?

-Ry -rY -ry -RY

Which of the following are examples of environmental effects on phenotype?

-The number of seeds eaten by a bird affects its weight. -The amount of sunlight experienced by a sunflower affects the number of seeds produced.

Prior to the 20th century, the two main ideas that provided the basis for most thinking about heredity were

-heredity occurs within species -traits are transmitted directly from parents to offspring

Examples of environmental influences on phenotype include

-the pattern of coat color in Siamese cats -the pattern of coat color in Himalayan rabbits

What is the probability that a mother with type A blood and genotype IAi and a father with type AB blood will produce a child with AB blood?

.25

In a homozygous recessive individual the probability of the the dominant allele being present is

0

The probability that a gamete produced by this mouse will have two "A" alleles is ____.

0

The expected frequency of F₁ plants with the genotype AA is _____.

0%

Two individuals heterozygous for gene Q produced gametes by meiosis, then mated and fertilized one egg. What is the probability that both the egg and sperm will carry the recessive allele?

0.25

In a heterozygous individual, the probability of a recessive allele being present in a gamete is

0.5

the three stages of Mendel's experiments

1)allowing plants to self-cross to ensure that they are true-breeding 2)recipricol crosses between true-breeding varieties 3)allowing hybrid offspring to self fertilize

Rank these steps of anthocyanin production in corn from first to last starting at the top.

1)starting molecules (colorless) 2)intermediet (colorless) 3)anthocyanin (purple)

The probability that a gamete produced by this mouse will have all four dominant alleles (ABCD) is _____.

1/16

If you are tossing a six-sided die, what is the probability of getting either a 3 or a 4 on your third toss AND a 6 on your fourth toss?

1/18

In the cross of Pp x Pp four outcomes are possible: PP, Pp, pP, and pp. The probability of being heterozygous is ________.

1/2

The probability that a gamete produced by this mouse will have one "A" allele is _____.

1/2

The probability that their first child will have dimples is ______.

1/2

The probability that a gamete produced by this mouse will have one "A" allele and one "B" allele is _____.

1/4

The probability that a gamete produced by this mouse will have either all four dominant alleles (ABDE) or all 4 recessive alleles (abcd) is ______.

1/8

The probability that their first child will have dimples and slender eyebrows is ______.

1/8

The genotype of the gametes produced by the plant with yellow pods is _______.

100% a

In a certain plant, fruit color is affected by an epistatic interaction between two genes. The fruit is red in the presence of at least one dominant allele of either or both gene A or gene B, and white when there are no dominant alleles present. What proportion of the offspring of a cross of AaBb x AaBb plants is expected to be red?

15/16

If a house cat has 76 total chromosomes in its diploid genome, how many sister chromatids would a cell have at the end of metaphase of meiosis I?

152

Cells from the fruit fly Drosophila melanogaster contain four pairs of chromosomes. What is the number of possible sets of chromosome orientations during meiosis I?

16

How many possible allele combinations (consider all possible combinations, even those that are identical) are produced in the offspring of heterozygous parents in a dihybrid cross?

16

In humans, brown eyes are dominant to blue eyes. If a blue-eyed man has children with a brown-eyed woman whose mother has blue eyes, what is the expected genotypic ratio among the offspring?

1:1

A 3:1 phenotypic ratio in the F2 generation of a monohybrid cross represents this genotypic ratio:

1:2:1

One of the parents in a dihybrid cross has the genotype AABb. How many types of gametes can this parent produce?

2

a ______ cross follows the simultaneous inheritance of two different characters.

2-factor

When performing a monohybrid cross, Mendel noticed that not all individuals in the F2 generation were true breeding. What proportion were not?

2/3 of the F2 individuals exhibiting the dominant form were not true breeding.

Choose the two dominant alleles in the human ABO blood group system.

A B

An individual with Type A blood can receive transfusions of which of the following blood types?

A O

An individual with genotype Aa can produce which gamete(s)?

A and a

A mother with type A blood and genotype IAi and a father with blood type B and genotype IBi have children who grow up and become regular blood donors. Of the possible children, which genotype would have the least valuable blood to donate?

AB

The genotype of the heterozygous plant is _____.

Aa

Which of the following is an example of a testcross?

AaBb x aabb

traits with their characteristics in human

Albinism-> lack of melanin pigmentation Hemophilia-> inability of blood to clot property Polydactyly-> extra finger and toe Huntington disease-> degeneration of nervous system Sickle cell anemia-> defective hemoglobin

The trait for round (R) peas is dominant over the trait wrinkled (r) peas. What would happen if true-breeding round peas are crossed with true-breeding wrinkled peas?

All offspring will have round peas.

The cellular division that changes the chromosome ploidy number from 2n to 1n occurs during

Anaphase of Meiosis I.

A person with type B blood can receive blood from people with which allele combinations?

B

Of the following alleles for blood type, indicate which two alleles are codominant to each other.

B A

When type B blood is given to a person with type A blood

B antigen from the donor reacts with anti-B antibody in the recipient.

Which of the following is NOT one of the three main stages that Mendel conducted his experiments in?

Back crosses between F1 and P individuals

The genotype of the man is ____.

DdBb

What type of cross follows the simultaneous inheritance of two different traits?

Dihybrid cross

In a typical monohybrid cross, all of the offspring in which generation will exhibit a single trait without blending?

F1

Pedigree analysis is typically used for studying:

Human traits that follow simple inheritance patterns

Which of the following traits is NOT described correctly?

Huntington disease: wasting away of muscles during childhood

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

Which of the following conditions is inherited due to a dominant allele?

Juvenile glaucoma

The fact that maternal and paternal chromosome pairs line up randomly during metaphase of meiosis supports Mendel's

Law of Independent Assortment

If you examine 100 F₁ plants from the testcross and find that they all have purple flowers with tall stems, you should conclude that the genotype of your original pea plant is .

PPTT

If you examine 100 F₁ plants from the testcross and find that 44 have purple flowers with tall stems and 56 have purple flowers with short stems, you should conclude that the genotype of your original pea plant is _____.

PPTt

The physical appearance or other observable characteristic of an individual is called his/her _____.

Phenotype

A trait that has multiple genes contributing to its expression is known as which of the following?

Polygenic trait

If you examine 100 F₁ plants from the testcross and find that 53 have purple flowers with tall stems and 47 have white flowers with tall stems, you should conclude that the genotype of your original pea plant is ____.

PpTT

If you examine 100 F₁ plants from the testcross and find that 23 have purple flowers with tall stems, 26 have white flowers and tall stems, 24 have purple flowers with short stems, and 27 have white flowers with short stems, you should conclude that the genotype of your original pea plant is _____.

PpTt

Which of these traits is NOT correctly matched with its mode of inheritance?

Red-green color blindness: dominant

Which term is used to refer to plant varieties in which offspring produced from self-fertilization remain uniform from one generation to the next.

True-breeding

Which of these blood phenotypes is NOT properly matched with the sugar exhibited on red blood cells?

Type O - have galactosamine and galactose

A temperature-sensitive version of the enzyme ______ is responsible for the pattern of fur color in Siamese cats

Tyrosinase

When a polygenic trait is studied, individuals can be grouped in different categories based on their traits and the number of individuals per category can then be plotted to produce a histogram. The bell shaped histogram typically approaches

a normal distribution

The genotype of the plant with yellow pods is _____.

aa

Assuming independent assortment, which of the following are examples of gametes produced by an AaBb individual?

ab, AB

In order to predict the outcome of mutually exclusive events, this rule should be used:

addition

In pea plants, the allele T encodes for tall plants, while the allele t encodes for dwarf plants. If a true-breeding tall pea plant is crossed with a true-breeding dwarf pea plant what are the expected genotypes of the offspring?

all Tt

Mendel's observations supported the independent ______ hypothesis.

assortment

When continuous traits are graphed in the form of a histogram with the phenotype on the X-axis, and the frequency of individuals with that phenotype on the Y-axis, a _________ -shaped curve results.

bell

Prior to the work of Mendel, inheritance was viewed as resulting from

blending of traits from an offspring's parents.

Mendel was able to produce hybrids in pea plant by using a technique called _____-pollination.

cross

The genotype of the woman is ______.

ddBb

The form of a trait that is always expressed when crossing two true-breeding parents in a monohybrid cross is called

dominant

Synthesis of the pigment, anthocyanin, causes purple coloration of certain plant parts, for example, seeds in certain commercial corn varieties. Because anthocyanin is made through a sequence of reactions, a gene involved in this pathway can interfere with the phenotypic expression of another gene, which leads to modified Mendelian ratios in monohybrid crosses. This is an example of ____ ______ ______.

epistasis

When the interaction of genes alters genetic ratios, this is called .

epistasis

True or false: Due to the diploid nature of eukaryotic cells, a gene can never have more than two alleles in a population of organisms.

false

True or false: Mendel found that plants exhibiting the recessive trait were usually not true-breeding.

false

True or false: Mendel's observations did not support the independent assortment hypothesis.

false

An individual's total set of alleles for a particular trait is called his/her ________.

genotype

The phenotype of the heterozygous plant is ____.

green pods

The major role meiosis plays in chromosomal inheritance is to

halve the chromosome number from 2n to 1n.

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

heterozygotes and homozygotes

If the offspring from a testcross contain only heterozygotes, the genotype of the unknown parent must be

homozygous dominant

The results of a testcross indicate that all of the offspring have a dominant phenotype. The genotype of the parent in question must be

homozygous dominant

genotypes with the correct genetic symbols

homozygous dominant-> TT homozygous recesive-> tt heterozygous-> Tt

A mismatched blood transfusion may lead to agglutination in the blood due to a reaction carried out by which system of the body?

immune system

Prior to the 20th century, the most common explanation of inheritance can best be described as

inheritance results from a blending of traits within fixed, unchanging species.

A trait is most likely to exhibit continuous variation if it is controlled by

many gene loci, each with several possible alleles.

A cross in which only a single trait is considered is called a(n) _____ cross or single factor cross.

monohybrid

An experimental cross where only a single characteristic is considered (for example, flower color) is called

monohybrid

The inheritance patterns of many traits are (more or less) complex than simple Mendelian patterns.

more

In order to determine the likelihood of having a flipped coin come up on heads three times in a row, you would use the

multiplication rule

Events that cannot occur at the same time are called

mutually exclusive

In a _____ distribution, the values of a variable are distributed around a mean within a certain spread, which indicates the amount of variation in the variable.

normal

In a ______ distribution, the values of a variable are distributed around a mean within a certain spread, which indicates the amount of variation in the variable.

normal

A Punnett square has rows and columns which represent gametes made by males and females. At the intersection of each row and column we combine the corresponding gametes to produce the genotype of a potential ______.

offspring

Mutations in how many genes cause the symptoms of cystic fibrosis?

one

In the monohybrid crosses performed by Mendel, the F1 plants always displayed ____.

one trait

The ____ form of a trait is the one that is not expressed in the F1 generation of a monohybrid cross.

recessive

Which of the following takes place automatically within an individual garden pea plant if it is not disturbed?

self-fertilization

The physical basis for the segregation of alleles when gametes are formed is

separation of homologous chromosomes during anaphase I followed by separation of sister chromatids during anaphase II.

Coat color in Siamese cats and Himalayan rabbits is influenced by

temperature

The cross of an individual who has a dominant phenotype with an individual who is homozygous recessive for that gene is known as a

test cross

In order for Mendel's simple ratios to hold true, the following assumption must be made:

that the traits are inherited independently

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

the F2 generation of monohybrid crosses.