Bio. CH. 9

What is the basis of Mendel's laws? the behavior of chromosomes during prophase I and prophase II of meiosis the behavior of chromosomes during mitotic prophase the behavior of chromosomes during prophase Il of meiosis only the behavior of chromosomes during metaphase I and anaphase I of meiosis (x)

...

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes? 1:2:1 1:1 3:1 2:1

1:1

A couple has two female children. What is the probability that their next child will be male? 33% 50% 75% 25%

50%

Which of these crosses will only produce heterozygous offspring? AA x aa Aa x Aa Aa x aa AA x Aa

AA × aa

Hypophosphatemia (vitamin D-resistant rickets) is inherited as an sex-linked dominant trait. The relevant gene is found on the X chromosome. What is the expected outcome of a cross between a homozygous recessive woman and a man with hypophosphatemia? Fifty percent of their daughters and fifty percent of their sons exhibit hypophosphatemia Seventy-five percent of their offspring exhibit hypophosphatemia All of their daughters and none of their sons exhibit hypophosphatemia. All of their sons and none of their daughters exhibit hypophosphatemia.

All of their daughters and none of their sons exhibit hypophosphatemia.

______ genes violate Mendel's principle of independent assortment. Linked Dominant Pleiotropic Codominant

Linked

An individual with the genotype AaBb produces four different gametes in equal proportions. This is a demonstration of ______. Mendel's principle of segregation Mendel's law of independent assortment the chromosomal theory of inheritance linkage

Mendel's law of independent assortment

What is the key to the recognition of codominance? The dominant allele is not always expressed The alleles affect more than one trait. The phenotype of the heterozygote falls between the phenotypes of the homozygotes. The heterozygote expresses the phenotype of both homozygotes.

The heterozygote expresses the phenotype of both homozygotes.

What is the key to the recognition of incomplete dominance? The trait exhibits a continuous distribution The heterozygote expresses the phenotype of both homozygotes The alleles affect more than one trait The phenotype of the heterozygote falls between the phenotypes of the homozygotes

The phenotype of the heterozygote falls between the phenotypes of the homozygotes.

A true-breeding plant that produces yellow seeds is crossed with a true-breeding plant that produces green seeds. The seeds of all of the offspring are yellow. Why? The yellow allele is recessive to the green allele The yellow allele is dominant to the green allele. All of the offspring are homozygous yellow. Yellow is an easier color to produce.

The yellow allele is dominant to the green allele.

Alleles are described as ______. environmental factors that affect gene expression alternate versions of a gene homologous chromosomes alternate phenotypes

alternate versions of a gene

Which of the following techniques is used to collect fetal cells during pregnancy for genetic testing? amniocentesis dihybrid cross pedigree analysis testcross

amniocentesis

An individual who is homozygous ______. carries two different alleles for a gene is a carrier of a genetic disorder carries two copies of the same allele for a gene expresses the dominant trait

carries two copies of the same allele for a gene

Mendel crossed true-breeding purple-flowered plants with true-breeding white-flowered plants, and all of the resulting offspring produced purple flowers. The allele for purple flowers is ______. monohybrid independent dominant segregated

dominant

According to Mendel's law of segregation, ______. more gametes carrying the dominant allele are produced than gametes carrying the recessive allele gametes have one copy of each allele homologous chromosomes move to the same gamete two alleles segregate into each gamete

gametes have one copy of each allele

In humans, the inheritance of ______ is best explained as being polygenic blood type Huntington's disease cystic fibrosis height

height

Many human traits, such as our performance on intelligence tests or our susceptibility to heart disease, are ______. determined only by our genes determined only by our environment influenced by both genes and the environment not affected by our genes

influenced by both genes and the environment

To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ______. expresses the dominant trait has the genotype Aa is homozygous recessive for that trait is homozygous dominant for that trait

is homozygous recessive for that trait

The best definition of a true-breeding plant is one that ______. self-fertilizes to produce hybrid offspring cannot be cross-fertilized self-fertilizes to produce offspring identical to the parent produces sterile offspring when cross-fertilized

self-fertilizes to produce offspring identical to the parent

The ______ is most commonly found in nature parental recessive trait wild-type trait dominant trait

wild-type trait