Term | Definition |
genetics | the study of heredity and variation of living organisms and how genetic information is passed from one generation to the next |
somatic cell | a plant or animal cell that forms the body of the organism; excludes reproductive cells |
chromosome | a structure in the nucleus that contains DNA |
sister chromatid | one of two chromosomes that are genetically identical and held together at the centromere |
centromere | the region where two sister chromatids are held together in a chromosome |
spindle fibre | a microtubule structure that facilitates the movement of chromosomes within a cell |
centrosome | a structure that helps to form the spindle fibres |
genome | the complete DNA sequence of an organism |
sex chromosome | an X or Y chromosome, which determines the genetic sex of an organism |
autosome | a chromosome that is not involved in determining the sex of an organism |
homologous chromosome | a chromosome that contains the same sequence of genes as another chromosome |
gene | a part of a chromosome that governs the expression of a trait and is passed on to offspring; it has a specific DNA sequence |
allele | a different form of the same gene |
karyotype | a photograph of pairs of homologous chromosomes in cell |
asexual reproduction | reproduction that requires only one parent and produces genetically identical offspring |
sexual reproduction | reproduction that requires two parents and produces genetically distinct offspring |
gamete | a male or female reproductive cell |
zygote | a cell formed by the fusion of two gametes |
fertilization | in humans, the joining of male and female haploid gametes |
haploid | a cell that contains half the number of chromosomes as the parent cell |
diploid | a cell that contains pairs of homologous chromosomes |
meiosis | the cellular process that produces cells containing half the number of chromosomes as the parent cell |
synapsis | the aligning of homologous chromosomes during prophase 1 in meiosis 1 |
spermatogenesis | the process of producing male gametes (sperm) in mammals |
oogenesis | the process of producing female gametes (eggs) in mammals |
crossing over | the exchange of chromosomal segments between a pair of homologous chromosomes |
non-disjunction | the failure of homologous chromosome pairs or sister chromatids to separate during meiosis |
monosomy | the loss of a chromosome as a result of non-disjunction |
trisomy | the gain of an extra chromosome as a result of non-disjunction |
selective breeding | the process of breeding plants and animals for desirable traits |
artificial insemination | the process by which sperm are collected and concentrated before being introduced into the female's reproductive system |
embryo transfer | the process by which an egg that has been fertilized artificially is transferred into a recipient female's uterus |
in vitro fertilization | the technique used to fertilize egg cells outside the female's body |
cloning | a process that produces identical copies of genes, cells, or organisms |
gene cloning | the use of DNA manipulation techniques to produce multiple copies of a single gene or segment of DNA |
recombinant DNA | a molecule of DNA that includes genetic material from different sources |
therapeutic cloning | the process of replacing an egg cell's nucleus with the nucleus from a somatic donor cell of genetically identical cells |
reproductive cloning | the process of producing genetically identical organisms |
stem cell | an undifferentiated cell that can develop and become specialized into different cell types of the body |