The Cell Cycle

Chromatin A combination of DNA and protein molecules

Chromosomes As a cell prepares to divide, its chromatin fibers condense, becoming visible as a compact structure

Sister Chromatids Two identical, joined copies of chromosomes

Centromere The region where the two chromatids are joined tightly together

Crossing Over The exchange of genetic material between homologous chromosomes

Spindle Apparatus (Fiber) Involved in moving and separating chromosomes during nuclear division

Homologous Chromosomes Two chromosomes of each matching pair; one inherited from each parent

Gametes Sex cells – egg and sperm

Haploid A cell with a single set of chromosomes Sex cells – 23

Diploid Contain two homologous sets of chromosomes In humans – 46

The Cell Cycle Consists of G1 phase, S phase, G2 phase, Mitosis, and Cytokinesis

G1 Phase Cell is growing and performing normal functions

S Phase Cell replicates its DNA

G2 Phase Cell makes microtubules in preparation for cell division

Interphase G1, S, and G2 phases combined

Mitosis Chromosomes move to opposite poles of the cell. Nucleus divides.

Cytokinesis Cytoplasm divides. Two daughter cells are formed

http://www.youtube.com/watch?v=Q6ucKWIIFmg http://www.youtube.com/watch?v=65SODTL_QsA