CH 7 Chromosomes and Sex-linkage

These flashcards cover key vocabulary terms and definitions related to chromosomes and sex-linkage, aiding in exam preparation.

Chromosomes

Cellular structures that transmit genetic information.

Chromosome Theory of Inheritance

The idea that genes are located on physical structures - chromosomes.

Diploid

A cell with two sets of chromosomes (2n).

Haploid

A cell with one set of chromosomes (n).

Meiosis

The process that produces haploid gametes from diploid germ cells.

Fertilization

The union of haploid gametes to produce a diploid zygote.

Sister chromatids

Identical copies of a replicated chromosome attached at the centromere.

Homologous chromosomes

Chromosomes that are matched in size, shape, and banding patterns, containing the same set of genes.

Nonhomologous chromosomes

Chromosomes that carry completely unrelated sets of genes.

Sex Chromosomes

Chromosomes that determine the sex of an organism (X and Y in humans).

Autosomes

All chromosomes except for the sex chromosomes X and Y.

Karyotype

A micrograph of stained chromosomes arranged in homologous pairs.

Heterogametic sex

The gender with two different kinds of gametes (e.g., XY males).

Homogametic sex

The gender with one type of gamete (e.g., XX females).

SRY gene

The primary determinant of maleness, found on the Y chromosome.

Drosophila

A genus of small flies used as a model organism in genetics.

Nondisjunction

An error in meiosis where chromosomes fail to separate properly, affecting sex chromosomes.

Gametogenesis

The formation of gametes through specialized processes involving meiosis.

Pedigree analysis

A chart used to trace the inheritance of traits in a family.

X-linked traits

Traits determined by genes on the X chromosome.

Crisscross inheritance

Pattern where daughters inherit their father's traits and sons inherit their mother's traits, commonly seen in X-linked recessive traits.

X-linked recessive

A trait that is not passed from father to son and affects females as carriers.

X-linked dominant

A trait that is observed in every generation and affects both males and females.

Dosage compensation

The mechanism that equalizes the expression of X-linked genes in males and females.

Barr body

The inactivated X chromosome in female cells, condensed and not expressed.

Sex-influenced traits

Traits that appear in both sexes but may express differently due to hormonal influences.

Sex-limited traits

Traits that affect characteristics found only in one sex.

Meiosis I

The first division of meiosis that separates homologous chromosomes.

Meiosis II

The second division of meiosis that separates sister chromatids.

Germ cells

Precursor cells that develop into gametes.

Somatic cells

The majority of cells in an organism that are not involved in reproduction.

Fertilized egg

A diploid zygote formed by the union of male and female gametes.

Genetic diversity

The variation in the genetic makeup among individuals.

Phenotype

The observable traits or characteristics of an organism.

Alleles

Different forms of a gene that can exist at a specific locus.

Embryogenesis

The process by which an embryo forms and develops.

Chromatin

The material consisting of DNA and proteins that make up chromosomes.