Ch07 Key Terms-2 - Tagged

alternation of generations

A life-cycle type in which the diploid and haploid stages alternate.

aneuploid

An individual with an error in chromosome number; includes deletions and duplications of chromosome segments.

autosome

Any of the non-sex chromosomes.

chiasmata

The structure that forms at the crossover points after genetic material is exchanged.

crossing over

The exchange of genetic material between homologous chromosomes resulting in chromosomes that incorporate genes from both parents.

euploid

An individual with the appropriate number of chromosomes for their species.

fertilization

The union of two haploid cells typically from two individual organisms.

germ cell

A specialized cell that produces gametes, such as eggs or sperm.

interkinesis

A period of rest that may occur between meiosis I and meiosis II; there is no replication of DNA during this period.

karyogram

The photographic image of a karyotype.

karyotype

The number and appearance of an individual's chromosomes, including the size, banding patterns, and centromere position.

life cycle

The sequence of events in the development of an organism and the production of cells that produce offspring.

meiosis

A nuclear division process that results in four haploid cells.

meiosis I

The first round of meiotic cell division; referred to as reduction division because the resulting cells are haploid.

meiosis II

The second round of meiotic cell division following meiosis I; sister chromatids are separated from each other, resulting in four unique haploid cells.

nondisjunction

The failure of synapsed homologs to completely separate and migrate to separate poles during the first cell division of meiosis.

polyploid

An individual with an incorrect number of chromosome sets.

recombinant

Describing something composed of genetic material from two sources, such as a chromosome with both maternal and paternal segments of DNA.

somatic cell

All the cells of a multicellular organism except the gamete-forming cells.

synapsis

The formation of a close association between homologous chromosomes during prophase I.

tetrad

Two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I.