Chapter 13, 14, 15 AP Biology

If 2n=48 for a particular cell, then the chromosome number in each cell after meiosis would be

24

Trisomy

3 copies of a chromosome

Barr Body

A dense object lying along the inside of the nuclear envelope in female mammalian cells, representing an inactivated X chromosome.

linkage map

A map of the genes on a chromosome based on linkage analysis; order genes based on recombination frequencies

In the pedigree above, squares represent males and circles represent females, individuals who express a particular trait are represented by shaded figures. Which of the following patterns of inheritance best explains the transmission of the trait?

Autosomal dominant

autosomal recessive

Both parents of an affected person are carriers; not typically seen in every generation

Mitochondrial

Can affect both males and females, but only passed on by females Can appear in every generation

Monosomy

Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number

autosomal dominant

Each affected person usually has an affected parent; occurs in every generation

X-linked dominant

Females are more frequently affected because all daughters and no sons of an affected man will be affected; can have affected males and females in same generation if mother is affected

Meiosis I

Homologous chromosomes separate into 2 diploid cells

Based on thedata in the Table 1, which of the following best explains why there are no individuals with constricted pods in the F1 generation?

Inflated pod shape is dominant to constrict pod shape

All of the following are the true statements about meiosis in mammals except

It produces 4 genetically identical gametes

X-linked recessive

Males are more frequently affected; affected males often present in each generation

Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes how mitosis and meiosis result in daughter cells with different number of chromosomes?

Mitosis produces two identical diploid daughter cells after one round of cell division. Meiosis produces four haploid daughter cells after two rounds of division

A blue-flowered African violet of unknown ancestry self-pollinated and produced 50 seeds. These seeds germinate and grow into flowering plants. Of these plants, 36 produce blue flowers and 14 produce pink flowers. What is the best explanation for the pink-flowering offspring?

Pink flower color is a trait recessive to blue flower color

Which of the following represents a cross between a white-eyed female and a red-eyed male?

RrXtXt • RrXtY

In humans, red-green color blindness is a sex-linked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true?

The mother carries the allele for color blindness

Mendel's 1st Law of Segregation

Traits are controlled by pairs of alleles which separate at gamete formation. Each gamete carries only one allele for each trait

inversion

a chromosome rearrangement in which a segment of a chromosome is reversed end to end

What did Morgan discover?

a mutation in male white eyed fruit flies that represented sex-linked traits

deletions

a mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication

duplication

a type of mutation that involves the production of one or more copies of a gene or region of chromosome

genomic imprinting

epigenetic phenomenon that causes genes to be expressed in a parent-of-origin-specific manner

chromosomal theory of inheritance

genes are found at specific locations on chromosomes and that the behavior of chromosomes during meiosis and fertilization accounts for inheritance

Mendel's 2nd Law of Independent Assortment

genes for different traits assort independently of one another in the formation of gamates

unlinked genes

genes that are far apart on a chromosome , they assort independently

gene silencing

genomic imprinting

linked genes

located near each other on the same chromosome

Recombination

molecule of DNA that has been modified to include genes from multiple sources (done through lab testing)

Mendel's 3rd Law of Dominance

one of the factors for a pair of inherited traits will be dominant and other recessive, unless both are recessive

Mosaic

presence of two different genotypes in an individual which developed from a single fertilized egg (x chromosome inactivation)

Meiosis II

sister chromatids separate into 4 haploid cells

Haploidy

state of having half of the set of the homologous chromosomes relative to a somatic cell

Nondisjunction

the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.

Gene Theory

the idea that the characteristics of living things are controlled by genes, which are passed from parents to their offspring.

translocation

the movement of a segment of DNA from one chromosome to another, which results in a change in the position of the segment

wild type

the phenotype for a character most commonly observed in natural populations

Aneuploidy

the presence of an abnormal number of chromosomes in a cell