Alleles may code for alternative expressions of a genetic trait.
True/False

True

An unremitting, fatal nervous system disease involving degeneration of the basal nuclei.

Huntington's disease

A particular gene's allele received by a gamete has no influence over selection of a different gene's allele.

Independent assortment

A Punnett square is a diagram that may be used to figure out the possible combinations of genes for a trait.
True/False

True

Chromosomes regulating most body characteristics.

Autosomes

CRISPR-Cas9 refers to a(n) ________.
a. technique used to change and edit sequences of DNA b. locus on a chromosome where the trait for sickle-cell anemia is carried c. technique for creating a karyotype of one's chromosomes d. enzyme responsible for self-destructing mutated cells

a. technique used to change and edit sequences of DNA

Distribution of chromosomes to different gametes.

Chromosome segregation

Environmentally produced phenotypes that mimic conditions that may be caused by genetic mutation are called phenocopies.
True/False

True

Errors in mitochondrial DNA are likely to cause genetic disorders associated with ________.
a. oxidative phosphorylation b. glycolysis c. gametogenesis d. nondisjunction

a. oxidative phosphorylation

Gene mutations in the X chromosome would tend to become visibly expressed ________.
a. more frequently in males b. more frequently in females c. equally frequently in both sexes d. in neither males nor females

a. more frequently in males

Genes for the same trait that have different expressions.

Allele

Genes not expressed unless they are present in homozygous condition.

Recessive

Genetic variation results from the crossing over and exchange of chromosomal parts that occur during meiosis II.
True/False

False

Genomic imprinting refers to the methylation of an allele during gamete formation that causes one parent's allele to be expressed and the other parent's allele to be ignored.
True/False

True

How many alleles exist for a given gene?
a. Only two alleles can exist per gene. b. Each gene can have a different number of alleles. c. Four alleles exist per gene, two from each parent. d. Only one allele can exist per gene.

b. Each gene can have a different number of alleles.

If a digital image is made of chromosomes in a cell going through mitosis, and the chromosomes are sorted and paired, the resulting display is a ________.
a. phenotype b. karyotype c. genome d. genotype

b. karyotype

If a person is homozygous for a particular trait this means ________.
a. the person cannot pass on that trait b. the person will not have a recessive condition c. the person has two identical alleles for the gene responsible for the trait d. the person has two dominant alleles for the gene responsible for the trait

c. the person has two identical alleles for the gene responsible for the trait

Inheritance of the ABO blood group type is an example of this type of inheritance.

Multiple-allele inheritance

Inheritance that results in continuous or qualitative phenotypic variations between two extremes; an example is skin color.

Polygenic inheritance

Inherited traits determined by genes on the X or Y chromosomes.

Sex-linked inheritance

In incomplete dominance, the heterozygote has an intermediate phenotype between that of homozygous dominant and homozygous recessive individuals.
True/False

True

________ is the most common type of fetal testing.
a. Blood chemistry b. Amniocentesis c. A DNA probe d. CVS

b. Amniocentesis

Lack of skin pigmentation.

Albinism

Means by which genes trade places, some maternal and some paternal, on each chromosome.

Chromosome crossover

Mitochondrial genes are free of errors. As a result, all genetic problems are due exclusively to nuclear genes.
True/False

False

Of the different sources of genetic variability, which one could be defined as permanent, transmissible changes to the DNA coding sequence often caused by outside environmental factors?
a. independent assortment b. crossing over c. random fertilization d. mutation

d. mutation

Of the different sources of genetic variability, which one produces the variation in the combinations of alleles on a single chromosome?
a. independent assortment b. crossing over c. random fertilization d. mutation

b. crossing over

Rare type of dwarfism resulting from an impaired ability of the fetus to lengthen long bones by endochondral ossification.

Achondroplasia

Recessive alleles are best defined as ________.
a. a deleterious or disease-causing allele b. a weakened or attenuated allele c. an allele only expressed when the allele is homozygous d. the least frequently expressed allele in a given population

c. an allele only expressed when the allele is homozygous

Recessive genes are usually expressed in humans only when ________.
a. they are coding for skin color b. they are coding for genetic diseases c. the organism is in the embryonic stage d. both alleles for the gene are exactly the same, or homozygous

d. both alleles for the gene are exactly the same, or homozygous

Results in chromosomes that have mixed contributions from each parent.

Gene recombination

Situation in which an individual has different alleles making up the genotype for a particular trait.

Heterozygous

Situation in which an individual requires identical alleles for that particular trait to be expressed.

Homozygous

Steven has the dominant tongue rolling phenotype but he does not know his genotype. His wife has the recessive non-tongue rolling trait. If their son cannot roll his tongue this means ________.
a. Steven has a heterozygous genotype b. Steven has a homozygous dominant genotype c. Steven has a homozygous recessive genotype d. that it is impossible to tell Steven's genotype from this information alone

a. Steven has a heterozygous genotype

The dominant gene is expressed when present; the recessive gene is expressed only in the absence of the dominant gene.

Dominant-recessive

The epigenetic mark that silences the expression of a gene is ________ bound to the DNA or histone proteins.
a. a methyl group b. an acetyl group c. an amine group d. a carboxyl group

a. a methyl group

The expression of all physical traits is strictly due to the inheritance of specific genes.
True/False

False

The gene allele that suppresses or masks the expression of the other allele.

Dominant

The gene responsible for the condition known as sickle-cell anemia demonstrates ________.
a. incomplete dominance b. a dominant genetic disorder c. a sex-linked genetic disorder d. a recessive genetic disorder

a. incomplete dominance

The heterozygote has a phenotype intermediate between those of the homozygous dominant and homozygous recessive.

Incomplete dominance

The main way a recessive allele would be fully expressed even when only one copy is present would be ________.
a. co-dominance b. recessive inheritance c. sex-linked inheritance d. incomplete dominance

c. sex-linked inheritance

The same allele can have a different effect depending on which parent it comes from.
True/False

True

Two alleles expressing exactly the same information for a trait are described as ________.
a. hemizygous b. monogamous c. heterozygous d. homozygous

d. homozygous

When genes are on the X or Y chromosomes, they are considered X-linked.
True/False

False

Which event can directly produce one chromosome containing both maternal and paternal genes?
a. crossing-over and independent assortment b. one chromosome can never have genes from both parents c. independent assortment only d. crossing-over only

d. crossing-over only

Which is NOT one of the ways in which small, non-coding RNA-enzyme complexes influence gene expression?
a. destroying the target mRNA b. destroying the peptide generated by the translation of the target mRNA c. inhibiting translation of the target mRNA into a peptide d. blocking the transcription of the gene that codes for the target mRNA

b. destroying the peptide generated by the translation of the target mRNA

Which of the following best describes genotypes and phenotypes?
a. A trait that is expressed such as eye color is the phenotype and the gene responsible for eye color is the genotype. b. A person's genotypes often change during their lifetime, but their phenotypes typically do not. c. A person's genotypes and phenotypes are typically unchanging during their lifetime. d. A person's genotypes and phenotypes often both change during their lifetime.

a. A trait that is expressed such as eye color is the phenotype and the gene responsible for eye color is the genotype.

Which of the following statements is true concerning genetic screening?
a. Screening is illegal in over half of the world. b. Screening can be done only in the first trimester of pregnancy. c. Genetic screening is rarely done because it yields very little accurate information. d. Screening can be done before conception by carrier recognition or during fetal testing.

d. Screening can be done before conception by carrier recognition or during fetal testing.