Bio Chapter 12-13 Study Guide

When an individual with the genotype AA is crossed with an individual with the genotype Aa, what is the probability of producing an offspring with the genotype AA?

1/2

In fruit flies, eye color is an X-linked trait, and red eyes are dominant to white eyes. If a heterozygous red-eyed female is crossed with a red-eyed male fly, the offspring would include which of the following? Choose all that apply.

100% of female flies having red eyes and 50% of male flies having white eyes 75% of all flies having red eyes and 25% having white eyes

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

1:2:1

A Punnett square for a single trait should be set up as a ______ square.

2 x 2

If you perform the monohybrid cross represented by Bb x Bb and examine 400 offspring of that cross, approximately how many offspring should have the genotype Bb?

200

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

3:1

In a typical monohybrid cross where the parents are true-breeding, what percentage of the offspring in the F2 generation is not true breeding?

50%

If a red-eyed male fruit fly is crossed with a heterozygous red-eyed female fruit fly, what eye colors will be observed in the offspring?

50% of the male flies will have red eyes, and 50% will have white eyes. All of the female flies will have red eyes.

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

9:3:3:1

What causes sickle-cell anemia?

A mutation in a protein-coding gene

Which of the following is an example of a testcross?

AaBb x aabb

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.

Identify the type of inheritance for sickle cell anemia.

Autosomal recessive

___ is the term for any chromosome that is not a sex chromosome.

Autosome or autosome

In the early 1900s observations that similar chromosomes paired with one another during the process of meiosis led to the formulation of the ___ of inheritance.

Chromosomal Theory

The heterozygote shows some aspect of both homozygotes in which of the following?

Codominance

What is the phenotype of an individual who is heterozygous for the sickle cell allele in an environment with normal oxygen levels?

Does not have sickle cell anemia

Choose the 4 reasons that contributed to Mendel selecting the garden pea as his experimental subject.

Earlier investigators had produced hybrid peas. Garden peas can self-fertilize. There were a large number of pure varieties. The garden pea had a relatively short generation time.

Most human monosomies are lethal during which of the following?

Embryonic development

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

F1

When two true-breeding varieties are crossed, they produce offspring that is typically called the ____.

F1 generation

When two true-breeding varieties are crossed, they produce a certain number of offspring. When this offspring is allowed to self-fertilize, they produce a generation that is referred to as the ____.

F2 generation

What is nondisjunction?

Failure of homologues or sister chromatids to separate properly during meiosis

True or false: In an environment with normal oxygen levels, an individual who is heterozygous for the sickle cell gene will exhibit light or moderate symptoms of sickle cell anemia.

False

True or false: The phenotype of an organism influences its genotype through the proteins that are made in the organism's cells.

False

What are linked genes?

Genes that segregate together

This law states that in a dihybrid cross, the segregation of different allele pairs is independent.

Law of independent assortment

Genes that are close together and that segregate together are called which of the following?

Linked

How are mitochondria inherited in humans?

Maternal inheritance

What is the phenomenon called in which a trait of the offspring is solely determined by the value of the trait in the female parent because it is passed on via the organelles in the egg cell?

Maternal inheritance

Segregation of alleles occurs during which of the following processes?

Meiosis

The 3:1 ratio observed in the F2 generation of a monohybrid cross is referred to as the ___ ratio.

Mendelian

The loss of one copy of an autosome is called which of the following?

Monosomy

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

More

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

Polygenic trait

This 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.

Principle of Segregation

Crossing over occurs during which phase of meiosis?

Prophase I

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

Punnett square

When Mendel performed monohybrid crosses one of the parental traits was never expressed in the F1 generation. What did he call that trait?

Recessive

Select the rule of probability that is applied to events with mutually exclusive outcomes.

Rule of addition

Identify the human disease in which the protein hemoglobin is altered.

Sickle cell anemia

What is aneuploidy?

The gain or loss of a chromosome

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.

Which of the following rules states the probability that two or more independent events will occur is equal to the product of their individual probabilities?

The rule of multiplication

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

They were inexpensive to buy Long generation time

An individual who has gained an extra autosome is referred to as which of the following?

Trisomic

Which of the following is another name for Down syndrome?

Trisomy 21

Who first formulated the chromosomal theory of inheritance?

Walter Sutton

In a pedigree, an individual represented by a solid square is

a male exhibiting the trait that is studied.

The law of independent assortment states that in a dihybrid cross, the ___ of each gene assort independently.

alleles

Nondisjunction can lead to the gain or loss of a chromosome. What is the name of this condition?

aneuploidy

The concept of inheritance which suggested that parents make equal contributions to their offspring and that their genetic material blends together is called

blending inheritance

When genes are linked, it is less likely that ___ will occur

crossing over

If a true-breeding tall pea plant is crossed with a true-breeding dwarf pea plant and all of the offspring are tall plants, the trait "tall plant" is

dominant over "dwarf plant."

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

epistasis

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

genotype

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

An individual who carries two different alleles of a gene is termed ___ with respect to that gene.

heterozygous

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

heterozygous or heterozygote

Consider the "tall"/"short" traits of pea plants. A pea plant that carries two "tall" alleles is

homozygous or homozygote

The product rule states that the probability that two or more ___ events will occur is equal to the product of their individual probabilities.

independent

The product rule states that the probability that two or more ____ events will occur is equal to the product of their individual probabilities.

independent

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

independently

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

male or XY female or XX

In a particular plant, the pigmentation of the offspring depends exclusively on the pigmentation of the female parent. This phenomenon is known as ___ inheritance

maternal

In humans, mitochondria are inherited through a type of uniparental inheritance called ___ inheritance

maternal

In eukaryotic cells, in addition to the nucleus, ___ and ___ contain their own genetic material.

mitochondria chloroplasts

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.

What term describes the type of aneuploidy, in which an individual is missing one copy of an autosome?

monosomic or monosomy

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

one trait

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

phenotype

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

polygenic

Genes influence the phenotype of an organism by specifying the kinds of ___ that are made in the organism's cells.

proteins or polypeptides

The principle of ______ is that 2 alleles for a genes separate during gamete formation and are rejoined at random, one from each parent, during fertilization.

segregation

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

sex

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

that the traits are inherited independently

Mendel designated a dominant trait as the one

that was expressed in the F1 generation.

What term describes the type of aneuplody, in which an individual has gained an extra autosome?

trisomic, trisomy, or trisomics

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

zygote or offspring