aneuploidy
a condition in which the organism has an abnormal number of copies of a chromosome
asexual reproduction
a form of reproduction that does not involve fusion of gametes, producing offspring genetically identical to the parent
centromere
the point on a chromosome that attaches to the spindle fibers during cell division and at which sister chromatids are attached
chromosome
a structure that contains DNA, the genetic material that is passed from one generation to the next
crossing-over
the exchange of DNA between homologous chromosomes during meiosis
cytokinesis
the pinching off of the cytoplasm to form two new cells
diploid
having a double set of chromosomes in homologous pairs; the diploid condition is designated by 2n
gamete
the sex cell of a sexually reproducing organism, with a haploid set of chromosomes
gene
a unit of heritable material that codes for a particular trait
genetic disorder
any one of several diseases that are the result of mutations of damaged genes; they are often inherited
haploid
having a single set of chromosomes, which is half the total of the parent; the haploid condition is designated by 1n or n
homologous chromosomes
identical pairs of chromosomes which pair together during synapsis of meiosis I in diploid organisms
independent assortment
the random distribution of the pairs of genes on different chromosomes to the gametes during meiosis
meiosis
a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, resulting in the production of gametes
nondisjunction
the failure of chromosomes or chromatids to separate during anaphase I or II of meiosis that results in an uneven distribution of genetic material
oogenesis
the process of egg cell formation during meiosis
polar body
nonviable cell produced at the end of meiosis in females
polyploidy
a condition in which an organism has more than the normal full sets of chromosomes
sexual reproduction
a form of reproduction involving fusion of gametes, producing genetically unique offspring
spermatogenesis
the formation of sperm through the process of meiosis
spindle fiber
microtubule that attaches to chromosomes and pulls them to opposite poles of a cell during cell division
synapsis
the pairing of homologous chromosomes during prophase I of meiosis
tetrad
the two pairs of homologous chromosomes (which share the same genes) that are formed and align next to each other during prophase I of meiosis