Term
|
Definition
| The basic unit of heredity; a sequence of DNA nucleotides on a chromosome that encodes a protein, tRNA or rRNA molecule, or regulates the transcription of such a sequence. |
|
|
Term
|
Definition
| The position on a chromosome where a gene is located. |
|
|
Term
|
Definition
| One of two or more alternative states of a gene. |
|
|
Term
|
Definition
| A pair of the same kind of chromosome in a diploid cell. |
|
|
Term
|
Definition
| Having only one set of chromosomes in contrast to diploid. |
|
|
Term
|
Definition
| Having two sets of chromosomes; in animals twice the number characteristic of gametes. |
|
|
Term
|
Definition
| One of two identical copies of each chromosome, still linked at the centromere, produced as the chromosomes duplicate for mitotic division, similarly, one two identical copies of each homologues chromosome present in a tetrad at meiosis. |
|
|
Term
|
Definition
| A visible point of constriction on a chromosome that contains repeated DNA sequences that bind specific proteins. These proteins make up the kinetochore to whch microtubules attach during cell division. |
|
|
Term
|
Definition
| The first rond of cell division in meiosis; it is referred to as a "reduction division" because homologues chromosomes separate and the daughter cells have only the haploid number of chromosomes. |
|
|
Term
|
Definition
| The second round of division in meiosis during which the two haploid cells from meiosis 1 undergo a mitosis like division without DNA rplication to produce four haploid daugher cells. |
|
|
Term
|
Definition
| The point by point alignment (pairing) of homologous chromosomes that occurs before the first meiotic division; crossing over takes place during synapsis. |
|
|
Term
|
Definition
| An X-shaped figure that can be seen in the light microscope during meiosis; evidence of crossing over, where two chromatids have exchanged parts; chiasmata move to the ends of the chromosome arms as the homologues separate. |
|
|
Term
|
Definition
| In meiosis the exchange of corresponding chromatid segments between homologous chromosomes; responsible for genetic recombination between homologous chromosomes. |
|
|
Term
|
Definition
| A haploid reproductive cell. |
|
|
