cell division

Cell DivisionMitosis & Meiosis

Why cells divide?

Replace old, damaged or dead cells

Growth of organism (multicellular)

Reproduce new organisms

Prokaryotic Cell Division

Binary Fission:

Cell GrowsChromosome copies

Cell Splits Into Two

Eukaryotic Cell Division

2 kinds of cell division

Mitosis- Process in which 2 new cells with identical genetic material are made from the parent cell (1 diploid cell divides to produce 2 new diploid cells)

Meiosis- Process in which gametes (sex cells) are made in which they recieve half of the genetic information

Cell Cycle

Repeating events of life of a cell

Three events:

Interphase: cell growing (not dividing)

Mitosis or Meiosis: Genetic material dividing

Cytokinesis: Division of cell itself

Cell Cycle

Interphase

G1 phase

cell grows to mature size

S phase

Cell’s DNA copies

G2 phase

Cell prepares for cell division

G0 phase- cell no longer divides (nerve cells)

Interphase

MitosisDivision of chromosomes

4 Events

Prophase

Metaphase

Anaphase

Telophase

ProphaseChromatin (DNA) shortens and tightens into distinct rod-shaped chromosomes

Nucleus & nucleolus disappear

Two pairs of centrioles migrate to each pole of the cell and release spindle fibers that radiate throughout the cell and attach to the centromere of each chromosome

Metaphase

Each chromosome lines up at the equator of the cell

Anaphase

•Chromatids of each chromosome split and are pulled apart to opposite poles of the cell

Telophase

Chromosomes become less coiled and return to the less tightly coiled chromatin

Nucleus and nucleolus reappear in each new cell

Spindle fibers disappear

Cytokinesis

Cell & cytoplasm divide either by cleavage furrow in animal cells or cell plate in plant cells