Module 3

Which of the following best defines Mendel's law of segregation?

-Fertilization results in the production of an individual with two factors for each trait. -Each individual has two factors for each trait and produces gametes with one factor for each trait.

Select all of the following that are possible based on the human pedigree shown.

-Two unaffected individuals are able to have unaffected offspring. -An affected and unaffected individual are able to have unaffected offspring.

Place the following steps in order to describe how DNA is packaged into cells.

1. DNA is wrapped around histone proteins. 2. DNA is bundled into structures called nucleosomes. 3. DNA is coiled into chromosomes.

Place the following events in order to describe the human life cycle. Begin with fertilization at the top.

1. Fertilization results in the productions of a diploid zygote. 2. Mitosis results in a fully grown diploid fetus. 3. Mitosis results in a fully grown diploid human adult. 4. Meiosis results in the production of haploid gametes.

Select all of the following that result from meiosis in humans.

1. Select all of the following that result from meiosis in humans. 2. Gametes are genetically different from each other and the parent.

Which of the following are processes within meiosis that produce genetic variation in offspring?

1. crossing-over during prophase I 2. metaphase

During the human life cycle, __________ ,(haploid/diploid) zygotes grow into _______ , (haploid/diploid) adults through mitosis.

1. diploid 2. diploid

A(n) ______ allele masks the expression of an alternative form of the same gene; while a(n) ________ allele can be masked by other forms of the same gene.

1. dominant 2. recessive

Alleles that are ______ mask the expression of alleles that are ________ .

1. dominant 2. recessive

During the life cycle of humans, the process of _________ results in haploid gametes and the process of ________ results in diploid adult humans.

1. meiosis 2. mitosis

The ________ refers to an organism's physical appearance and characteristics, while the _______ refers to the combination of alleles it carries.

1. phenotype 2. genotype

Those chromosomes that determine if an individual is male or female are called _______ chromosomes, while all other chromosomes are called _______ chromosomes.

1. sex 2. autosomal

What is the probability of two parents, genotypes Tt and TT, having an offspring of genotype TT?

2/4

Which of the following best describes incomplete dominance?

A form of inheritance where the heterozygote expresses a phenotype that is an intermediate between the dominant and recessive phenotypes

Which of the following best describes codominance?

A non-Mendelian form of inheritance where the heterozygote displays both dominant phenotypes.

Which of the following scenarios best describes a codominant form of inheritance?

A white goat is bred with a black goat and the resulting offspring are both white with large black spots.

_____ are variations of a gene.

Alleles

Which of the following best describes alleles?

Alleles are variations of genes and include examples such as eye color, height, and ability to digest lactose.

Select all of the following that display non-Mendelian forms of dominance.

Codominance — Heterozygous genotypes full express both dominant phenotypes. Incomplete dominance — Heterozygous genotypes express an intermediary phenotype that is a blend between dominant and recessive phenotypes.

How does meiosis produce genetic variation in offspring?

Crossing-over during prophase I allows homologous chromosomes to swap alleles and homologous chromosomes are randomly aligned at the center of the cell during metaphase I.

Which of the following sentences is true about how DNA is packaged into chromosomes?

DNA is coiled around proteins and organized into bundles before being coiled into a chromosome.

Mask the appearance of other alleles of that same gene; only one is required for phenotypic expression

Dominant alleles

Which of the following best describes the difference between recessive and dominant forms of inheritance?

Dominant alleles mask recessive alleles. So, an individual must have two recessive alleles to express a recessive trait, but only one dominant allele to express a dominant trait.

Which of the following best explains Mendel's law of independent assortment?

For multiple-trait crosses, each pair of factors separates independently from the others, meaning all possible combinations of factors can occur in gametes.

Interpret the following scenario to describe one form of non-Mendelian inheritance: A parent with curly hair and a parent with straight hair have a child with wavy hair. Which interpretation is most likely to be accurate?

Hair texture may follow an incomplete dominance form of inheritance.

Choose the correct answer choice that describes how crossing-over in prophase I produces genetic variation.

Homologous chromosomes align closely together and swap alleles with each other, allowing for new genetic combinations in resulting gametes.

How does the shuffling of chromosomes during metaphase I allow for genetic variation?

Homologous chromosomes are shuffled as they are aligned along the center of the cell. Their alignment determines which chromosomes will end up in each daughter cell.

Which of the following best describes the role of meiosis during sexual reproduction?

Meiosis produces haploid gametes that are genetically different from each other and their parents.

Select all of the following that are stages of meiosis II.

Metaphase II Anaphase II

What sentence best defines nucleosomes?

Nucleosomes are small bundles of DNA wrapped around special proteins.

Which of the following best supports this statement: Traits are hereditary.

Our genes determine our specific traits. Because genes are inheritable, specific traits are inheritable also.

Place the stages of meiosis I in order, beginning with the first stage.

Prophase I Metaphase I Anaphase I Telophase I

Place the stages of meiosis II in the correct order, beginning with the first stage.

Prophase II Metaphase II Anaphase II Telophase II

Which statement best describes the inheritance of sickle-cell disease?

Sickle-cell disease is an autosomal recessive disease, meaning it is carried on recessive alleles and requires both diseased alleles in order to be expressed.

What is the most likely outcome to traits that are influenced by environmental factors?

Traits tend to be distributed in a bell-shaped curve with the majority of phenotypes favoring the average trait. For example, there are more people with medium height than either very short or very tall heights.

Which of the following best defines multiple allele inheritance?

When a trait is controlled by interactions between many different alleles.

In a pedigree displaying a family that carries sickle-cell disease, what would be the expected genotype of affected individuals?

aa

Variations in eye color, height, blood type, and physiological differences are considered to be the result of differences between the _______ of genes.

alleles

Variations in eye color, height, blood type, and physiological differences are considered to be the result of differences between the __________ of genes.

alleles

Variations of a gene are called _______ and include examples such as eye color, blood type, or height.

alleles

Select all of the following that are stages within meiosis I.

anaphase I telophase I prophase I metaphase I

Sickle-cell disease follows ________ inheritance, meaning it is carried on autosomal chromosomes and it requires two alleles to be expressed.

autosomal recessive

-22 pair (44 total) in adult females -Determine a range of traits, including the presence of sickle-cell disease, eye color, and height.

autosomal chromosomes

Genes carry instructions for making proteins or other gene products. This means that:

changes in genes can change our physical traits.

During sexual reproduction, meiosis is responsible for the production of haploid _________ (both male and female) that later fuse to form a diploid zygote.

gametes

The basic units of inheritance are called ______ and are carried on chromosomes.

genes

Units called _________ control our physical traits through controlling the manufacturing of proteins and other products.

genes

During crossing-over,

genetic variation is introduced as closely aligned homologous chromosomes swap alleles with each other.

An individual with the genotype Gg would be considered _____.

heterozygous

Hh

heterozygous

In order to be packaged into a chromosome, DNA is wound around ________ proteins to form bundles called nucleosomes.

histone

Two copies of different chromosomes, found in diploid organisms

homologous chromosomes

During metaphase I of meiosis,

homologous chromosomes are shuffled, paired, and aligned at the center of the cell, allowing for genetic variability in offspring.

-HH -hh

homozygous

An organism carrying two dominant alleles of a particular gene would be considered __ for that trait.

homozygous dominant

An individual with the genotype tt would have two recessive alleles for a trait. Another name for this genotype is

homozygous recessive

The law of _____ describes how each pair of factors separate independently of each other, so that all possible combinations of factors can occur in the gametes.

independent assortment

The inheritance of skin color

is controlled by both environmental and genetic influences.

In humans, __________, (females/males) have an X and Y chromosome for their sex chromosomes.

males

During the human life cycle, the process of _________ cuts the chromosome number in half in order for fertilization to double the chromosome number.

meiosis

If a phenotypic trait is influenced by several different alleles interacting with each other, it is said to be classified as _____.

multiple allele inheritance

In order to be packaged into a chromosome, DNA is wound around histone proteins to form a(n) _______ structure.

nucleosome

A rabbit has a brown-spotted coat that is controlled by two different alleles. A spotted coat results from a heterozygous allele combination. In this example, the brown coat is considered the rabbit's _____, while the heterozygous allele combination is considered the rabbit's _____.

phenotype; genotype

The _____ refers to an organism's physical appearance or characteristics, while the _____ refers to the allele combination it has.

phenotype; genotype

Interpret the following scenario to distinguish between recessive and dominant forms of inheritance. Two unaffected parents that are heterozygous for a genetic disease have a child with the genetic disease. This form of inheritance follows a _____ form of inheritance.

recessive

Are masked by other alleles of that same gene; two are required for phenotypic expression

recessive alleles

Mendel's law of ________ states that all individuals have two factors for each trait and produce gametes with one factor for each trait and that fertilization produces new individuals with two factors for each trait.

segregation

Chromosomes that vary depending on the sex of an individual are called _______ chromosomes.

sex

-XX in females; XY in males -Determine if an individual is male or female

sex chromosomes

The process where adult humans produce haploid gametes through meiosis is called

sexual reproduction

Two copies of the same single chromosome that are attached to each other physically

sister chromatids

Identical copies of the same chromosome are called ______, while two different copies of a chromosome are called _____.

sister chromatids; homologous chromosomes