VOCABULARY
asexual reproduction A type of reproduction involving only one parent that
produces genetically identical offspring by budding or by the division of a single cell
or the entire organism into two or more parts
autosome A chromosome that is not directly involved in determining sex, as
opposed to a sex chromosome
binary fission The type of cell division by which prokaryotes reproduce. Each
dividing daughter cell receives a copy of the single parental chromosome
cancer cells Do not have a properly functioning cell-cycle system; instead, they
divide excessively and can invade other tissues of the body
cell cycle An ordered sequence of events in the life of a eukaryotic cell, from its
origin in the division of a parent cell until its own division into two; composed of the
M, G1, S, and G2 phases
cell cycle control system A cyclically operating set of molecules in the cell that
triggers and coordinates key events in the cell cycle
crossing over The reciprocal exchange of genetic material between nonsister
chromatids during synapsis of meiosis I
cyclin A cellular protein that occurs in a cyclically fluctuating concentration and that
plays an important role in regulating the cell cycle.
cyclin dependent kinases A protein kinase that is active only when attached to a
particular cyclin
diploid cell A cell containing two sets of chromosomes (2n), one set inherited from
each parent
G0 A nondividing state occupied by cells that have left the cell cycle.
G1 The first gap, or growth phase, of the cell cycle, consisting of the portion of
interphase before DNA synthesis begins.
G2 The second gap, or growth phase, of the cell cycle, consisting of the portion of
interphase after DNA synthesis occurs.
genetic recombination The general term for the production of offspring with new
combinations of traits inherited from the two parents
genome The complete complement of an organism's genes; an organism's genetic
material
growth factor A protein that must be present in the extracellular environment
(culture medium or animal body) for the growth and normal development of certain
types of cells
haploid cell A cell containing only one set of chromosomes (n)
homologous chromosomes Chromosome pairs of the same length, centromere
position, and staining pattern that possess genes for the same characters at
corresponding loci. One homologous chromosome is inherited from the organism's
father, the other from the mother. Also called homologues or homologous pair.
independent assortment A general rule in inheritance that when gametes form
during meiosis, each pair of alleles for a particular characteristic segregate
independently; also known as Mendel's second law of inheritance
kinetochore A structure of proteins attached to the centromere that links each
sister chromatid to the mitotic spindle.
maturation promoting factor (MPF) Maturation-promoting factor (M-phasepromoting factor); a protein complex required for a cell to progress from late
interphase to mitosis. The active form consists of cyclin and a protein kinase.
meiosis A two-stage type of cell division in sexually reproducing organisms that
results in cells with half the chromosome number of the original cell
mitosis A process of nuclear division in eukaryotic cells conventionally divided into
four stages: prophase, metaphase, anaphase, and telophase. Mitosis conserves
chromosome number by equally allocating replicated chromosomes to each of the
daughter nuclei
mitotic phase The phase of the cell cycle that includes mitosis and cytokinesis
mitotic spindle An assemblage of microtubules and associated proteins that is
involved in the movements of chromosomes during mitosis
nondisjunction An accident of meiosis or mitosis, in which the members of a pair
of homologous chromosomes or sister chromatids fail to move apart properly
S phase The synthesis phase of the cell cycle; the portion of interphase during
which DNA is replicated.
sex chromosomes One of the pair of chromosomes responsible for determining
the sex of an individual
sexual reproduction A type of reproduction in which two parents give rise to
offspring that have unique combinations of genes inherited from the gametes of the
two parents
sister chromatids Replicated forms of a chromosome joined together by the
centromere and eventually separated during mitosis or meiosis II
somatic cell Any cell in a multicellular organism except a sperm or egg cell
zygote The diploid product of the union of haploid gametes in conception; a
fertilized egg