1.6 The Cell Cycle And Cell Division Flashcards
Chromosome
A long thin structure of dna and protein, in the nucleus of eukaryotic cells, carrying genes
Chromatid
One of the two identical copies of a chromosome, joined at the centromere, prior to cell division
Centromere
Specialised region of a chromosome where two chromatids join and to which the microtubules of the spindle attach at cell division
Haploid
Having one complete set of chromosomes (human gametes)
Diploid
Having two complete sets of chromosomes (human body cells)
Homologous
The chromosomes in a homologous pair are identical in size and shape and they carry the same gene loci, with genes for the same characteristics. One chromosome from each pair comes from each parent.
Mitosis
A type of cell division which produces two daughter cells that are genetically identical to & have the same no of chromosomes as the parent cell and each other
Cell cycle
The sequence of events that takes place between one cell division and the next
When does DNA replication occur in interphase
S phase
Meiosis
A two-stage (two divisions) cell division in sexually reproducing organisms that produces gametes. Produces 4 genetically different daughter cells each with half the number of chromosomes as the parent cell
Bivalent
The structure formed from the association of the two chromosomes of a homologous pair at prophase I of meiosis
Synapsis
The pairing of homologous chromosomes and crossing over at prophase I of meiosis
Chiasma (pl chiasmata)
The site at which two chromosomes exchange DNA in crossing over
Crossing over
The reciprocal exchange of genetic material between the chromatids of homologous chromosomes during synapsis in prophase I of meiosis
Independent assortment
Either of a pair of homologous chromosomes faces either pole at metaphase I of meiosis (independently of the chromosomes of the other homologous pairs) and either of a pair of sister chromatids faces either pole at metaphase II of meiosis (independently of the other chromatids of the other chromosomes)
