Chapter 7 Bio Vocab

aneuploid

an individual with an error in chromosome number; includes deletions of chromosome segments

autosome

any of the non-sex chromosomes

chiasmata

(singular = chiasma) the structure that forms at the crossover points after genetic material is exchanged

crossing over

(also, recombination) the exchange of genetic material between homologous chromosomes resulting in chromosomes that incorporate genes from both parents of the organism forming reproductive cells

euploid

an individual with the appropriate number of chromosomes for their species

germ cell

a specialized cell that produces gametes, such as egg or sperm

karyogram

the photographic image of a karyotype

karyotype

the number and appearance of an individuals chromosomes, including the size, banding patterns, and centromere position

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, and the result is four unique haploid cells

monosomy

an otherwise diploid genotype in which one chromosome is missing

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

somatic cells

all the cells of a multicellular organism except the gamete-forming cells

synpasis

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

trisomy

an otherwise diploid genotype in which one entire chromosome is duplicated

X inactivation

the condensation of X chromosomes into Barr bodies during embryonic development in females to compensate for the double genetic dose