Glossary of Key Terms
genetics - the study of heredity and variation of living organisms and how genetic information is passed from one generation onto the other
somatic cell - a plant or animal cell that forms the body of an organism; excludes reproductive cells
chromosome - a structure in the nucleus that contains DNA
sister chromatids – a chromosome and its duplicate, attached to one another by a centromere. The pair remains attached until separated during mitosis.
chromatin – the tangled fibrous complex of DNA and protein within a eukaryotic nucleas
centromere – the region where two sister chromatids are held together in a chromosome
centrosome - a structure that helps to form the spindle fibres
spindle fibres – protein structures that guide chromosomes during cell division
haploid – a cell that contains half the number of chromosomes as the parent cell
diploid - a cell that contains pairs of homologous chromosomes
prophase – the first phase of mitosis; chromosomes condense; centrioles assemble; spindle fibres attach to centromeres; nuclear membrane dissolves
interphase – the time interval between nuclear divisions. During this phase, a cell increases in mass, roughly doubles the cytoplasmic components, and duplicates its chromosomes
prophase – the first phase of mitosis; chromosomes condense; centrioles assemble; spindle fibres attach to centromeres; nuclear membrane begins to dissolve
metaphase – the second phase of mitosis; chromosomes line up at the equatorial plate; the nuclear membrane completely dissolves
anaphase – the third phase of mitosis; the centromeres divide and the resulting chromosomes move to opposite poles of the cell
telophase – the last phase of mitosis; chromosomes lengthen again; the spindle fibres dissolve, and a nuclear membrane forms around the chromosomes
cytokinesis – the division of cytoplasm
karyotype - a photograph of homologous chromosomes in a 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
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 I in meiosis I
spermatogenesis - the process of producing male games (sperm) in mammals
oogensis - the process of producing female games (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
cloning - the process that produces identical copies of genes, cells, or organisms
stem cell - an undifferentiated cell that can develop and become specialized into different cell types of the body
somatic cell - a plant or animal cell that forms the body of an organism; excludes reproductive cells
chromosome - a structure in the nucleus that contains DNA
sister chromatids – a chromosome and its duplicate, attached to one another by a centromere. The pair remains attached until separated during mitosis.
chromatin – the tangled fibrous complex of DNA and protein within a eukaryotic nucleas
centromere – the region where two sister chromatids are held together in a chromosome
centrosome - a structure that helps to form the spindle fibres
spindle fibres – protein structures that guide chromosomes during cell division
haploid – a cell that contains half the number of chromosomes as the parent cell
diploid - a cell that contains pairs of homologous chromosomes
prophase – the first phase of mitosis; chromosomes condense; centrioles assemble; spindle fibres attach to centromeres; nuclear membrane dissolves
interphase – the time interval between nuclear divisions. During this phase, a cell increases in mass, roughly doubles the cytoplasmic components, and duplicates its chromosomes
prophase – the first phase of mitosis; chromosomes condense; centrioles assemble; spindle fibres attach to centromeres; nuclear membrane begins to dissolve
metaphase – the second phase of mitosis; chromosomes line up at the equatorial plate; the nuclear membrane completely dissolves
anaphase – the third phase of mitosis; the centromeres divide and the resulting chromosomes move to opposite poles of the cell
telophase – the last phase of mitosis; chromosomes lengthen again; the spindle fibres dissolve, and a nuclear membrane forms around the chromosomes
cytokinesis – the division of cytoplasm
karyotype - a photograph of homologous chromosomes in a 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
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 I in meiosis I
spermatogenesis - the process of producing male games (sperm) in mammals
oogensis - the process of producing female games (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
cloning - the process that produces identical copies of genes, cells, or organisms
stem cell - an undifferentiated cell that can develop and become specialized into different cell types of the body