Mitosis (Cell Division) MITOSIS

Vocab 1.Cell Cycle: the life cycle of a eukaryotic cell, consisting of growth and division 2.Chromatin: uncoiled DNA 3.Chromosomes: coiled DNA and protein Chromatin

4.Chromatids: identical chromosome copies, ½ of the X shape chromosome 5.Centromere: holds the chromatids together Chromosome Chromatid Centromere

Vocab cont. 6.Homologous Chromosomes: a pair of chromosomes with matching information 7.Cytokinesis: when the cytoplasm divides after mitosis

Limits to Cell Growth: 1.DNA Overload: - DNA would not be able to instruct all of the activities going on in the cell 2.Exchanging Materials: - As the cell size increases it would be more difficult for a larger cell to get oxygen and nutrients in and wastes out

Cell Division process by which a cell divides and produces 2 IDENTICAL daughter cells Why do cells divide? 1) Growth of the organism 2) Repair damaged cells 3) Reproduction

The Steps of the Cell Cycle: 4 phases: 1. G1: cell growth

The Steps of the Cell Cycle: 4 phases: 1. G1: cell growth 2. S: DNA replication

The Steps of the Cell Cycle: 4 phases: 1. G1: cell growth 2. S: DNA replication 3. G2: cell growth

The Steps of the Cell Cycle: 4 phases: 1. G1: cell growth 2. S: DNA replication 3. G2: cell growth 4.Mitosis: cell division (P, M, A, T)

Interphase - this is the longest phase of the cell cycle and includes the G1, S, and G2 phases chromatin: (DNA) Nucleolus Nuclear Membrane Cell Membrane

Mitosis Cell Division of body cells Shortest phase of the Cell Cycle Consists of 4 phases 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase

Mitosis Step 1: Prophase - DNA coils up into chromosomes, with 2 copies of each chromosome (sister chromatids) held together by a centromere

Mitosis Step 1: Prophase cont. - Nucleolus and Nuclear Mem. disappear - Spindle fibers form Spindle Fibers Chromosomes

Mitosis Step 2: Metaphase - Chromosomes attach to spindle fibers by centromeres and line up across the middle Spindle Fibers 2 nd chromatid One chromatid Centromere

Mitosis Step 3: Anaphase - Centromeres split apart - Sister chromatids are pulled to opposite ends of the cell by the spindle fibers Spindle Fibers Centromere One chromatid 2 nd chromatid

Mitosis Step 4: Telophase Chromatids reach opposite ends of the cell Nucleolus and Nuclear Membrane reappears

Mitosis Step 4: Telophase - Cell membrane begins to separate - Cytokinesis occurs: division of cytoplasm - animal cells: cleavage furrow - plant cells: cell plate Cleavage Furrow (Animal cell only)

The Result: 2 new identical daughter cells, the old cell no longer exists

Animal Cell Mitosis

Plants Cell Plate