Chapter 19: Genetics and Inheritance

Punnett Square

A way to represent patterns of inheritance of alleles and predict probability that a particular allele will be inherited.

yes

A widow's peak in the hairline is a dominant trait. Could two people with widow's peaks produce a child with widow's peak?

sickle cell anemia

All of the following human traits are determined by interaction of multiple genes and alleles except:

XXY Klinefelter syndrome

Male phenotype, Long arms and legs, underdeveloped testes in boys, breast development.

XYY Jacob syndrome

Male phenotype, Unusually tall & thin, large teeth, sometimes experience severe acne, slightly lower IQ - mild form of retardation.

Karyotype

A display of the chromosome pairs of a cell arranged by size and shape.

The alleles on homologous chromosomes are identical to each other.

All of the following statements about homologous chromosomes are true except:

XO Turner Syndrome

Female phenotype, short with slightly altered body form and small breasts. Most are not mentally retarded but are sterile and have shortened lives.

Recessive

The allele that is only expressed if homozygous.

Genotype

The set of alleles that an individual possesses.

alleles, locus

Different types of genes for a trait are referred to as ______ and their location on chromosomes is referred to as their _______.

the individual is a female

Examination of a karyotype reveals 23 pairs of chromosomes, with each homologous pair illustrating similar size and centromere location. Which of the following can be concluded from this karyotype?

Dominant

Prevails over recessive genes.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during mitosis or meiosis.

Sex-linked inheritance

Traits located on the sex cells. (i.e. Colorblindness, hemophilia.)

Inheritance

Transmission of DNA from parents to offspring.

25%

Two parents are heterozygous for familial hypercholoesterolemia, having blood cholesterol levels two to three times the normal level. What is the probability that their child will be unaffected by this disorder?

Alleles

Alternate versions of a single gene.

Polygenic inheritance

Inheritance of phenotypic traits that depend on many genes.

Homozygous

An individual who possesses two identical alleles for a given gene.

Mutation

A change in an individuals DNA sequence that can be passed to future generations.

Dominant-lethal allele

A homozygous dominant or heterozygous combination of alleles results in death (e.g. Huntington's disease).

Linked alleles

Alleles for different traits are inherited together because they are joined on the same chromosome.

Heterozygous

An individual who possesses two different alleles for a given gene.

Codominance

Both alleles contribute to the phenotype of the organism.

Sickle cell anemia

Caused by inheriting defective recessive genes from both parents, more commonly occurs in African-Americans.

no

Could a couple with attached earlobes produce a baby with detached earlobes? (yes or no)

Incomplete dominance

Creates a blended phenotype; one allele is not completely dominant over the other

XXX Trisomy X syndrome

Female phenotype, nearly normal except for a tendency toward mild mental retardation.

1

How many different kinds of gametes (with respect to a particular gene locus) are formed by an individual who is homozygous?

All her sons will be color-blind

If a women is red-green color-blind, what can you state about all her sons?

dominant, recessive

In a heterozygote, the expressed trait is referred to as _______ and the unexpressed trait is referred to as________.

Law of segregation

Mendelian principle that diploid organisms inherit two genes for each trait (on a pair of homologous chromo-somes), and that during meiosis the two genes are distributed to different gametes.

Law of independent assortment

Mendelian principle that genetic factors separate completely independently of each other during the formation of sperm and egg, applies fully only to genes located on different chromosomes

Phenotype

The traits that an individual exhibits.

0%

What is likelihood that a man with hemophilia mating with a women who is homozygous for the normal form of the blood clotting factor gene will have a son with hemophilia?

independent assortment during gamete production; crossing-over and shuffling of linked genes during meiosis; random fertilization

What is the basis for the tremendous genetic diversity resulting from sexual reproduction?

0%

What is the likelihood that a parent with Type AB blood would have a child with Type O blood?

Punnett square analysis

What tool is used to determine the probabilities of different genetic outcomes from various crosses?

Deletion

When a piece of a chromosome breaks off and is lost.

Translocation

When a piece of chromosome breaks off and attaches at another site.

Klinefleter syndrome

Which of the following could be detected by preparing a karyotype?

nondisjunction

Which of the following events or processes can result in Patau syndrome, Turner Syndrome, or Klinefelter syndrome?

crossing-over during meiosis I

Which of the following results in the separation (or unlinking) of linked genes?

a dominant allele masks the expression of a recessive allele in a heterozygote

Which of the following statements correctly express the relationship between dominant and recessive alleles?

Genotype determines phenotype; Environment can affect phenotype

Which of the following statements is/are true?

adjacent genes on the same chromosome

Which of the following would provide an exception to Mendel's law of independent assortment?

genotype

Your allele combination for any trait is called your?