Chapter 12 Concept Questions

Human traits that follow simple inheritance patterns

Pedigree analysis is typically used for studying:

Pleiotropic

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

TT x Tt and Yy x yy

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?

Assortment

Mendel's observations supported the independent _________ hypothesis.

2

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

2x2

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

1:2:1

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

Zygote

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

Punnet

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

Dihybrid

A(n) ________ cross follows the simultaneous inheritance of two different characters.

Pleiotropic

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

Monohybrid

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

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

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).

heterozygous and homozygous

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

polygenic inheritance and independent segregation of genes

Continuous phenotypic variation results from

Homozygous dominant

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

F2 generation of monohybrid crosses

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

15/16

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?

50%

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

0

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

That the traits are inherited independently

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

Addition

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

Independent

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

More

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

Two monohybrid crosses

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

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

Pedigree

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

False

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's observations did not support the independent assortment hypothesis.

Dihybrid cross

What type of cross follows the simultaneous inheritance of two different traits? Multiple choice question.

Bell

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 _________ -chaped curve results

2/3

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

Epistasis

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

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.

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

Two alleles are usually the same

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)?

In a population of organisms, a gene can be represented by more than two alleles.

Which of the following statements about the number of alleles a gene can have is true? Multiple choice question.

Long generation time They were inexpensive

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

Punnet Square

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

Hypercholesterolemia Mid-digital hair Polydactyly

Which of these traits exhibit a dominant mode of inheritance?

Red-green color blindness: dominant

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