“Cell division is part of the cell cycle” Section 3.2 & 3.3

Do Now C A B Label the following diagram 1- chromosome 2- chromatid 3- centromere C A B

Objectives Describe the main events of the cell cycle Differentiate interphase from mitosis Construct a cell cycle model from paper plates.

Cell Cycle Two main phases: Interphase & M-phase (Mitosis) The normal sequence of development and division of a cell Two main phases: Interphase & M-phase (Mitosis)

Interphase G1: organelles duplicate, cell grows There is no division in interphase, just growth. G1: organelles duplicate, cell grows S: DNA replicates (is copied) G2: cell grows, prepares to divide

M-phase (Mitosis) Mitosis: Cellular Division (Nuclear Material divides!) PMAT+ C Prophase Metaphase Anaphase Telophase Cyokinesis

M I T O S I S

Mitosis Creates 2 genetically IDENTICAL daughter cells.

Prophase DNA condenses to form chromosomes. Each chromosome has 2 chromatids and a centromere The nuclear membrane disappears

Metaphase – “Middle” Chromosomes line up in the middle of the cell at the “equator”

Anaphase – “away” Chromatids split Spindles pull to opposite sides of the cell AWAY from each other

Telophase 2 Nuclei form Nuclear membrane forms around each group of chromosomes. The chromosomes become chromatin again.

Cytokinesis Division of the cytoplasm. Occurs differently in plant and animal cells. 2 New daughter cells!

http://cellsalive.com/mitosis.htm http://www.youtube.com/watch?v=pOsAbTi9tHw

Cytokinesis Animal Cells: Membrane pinches together and forms a cleavage furrow until the cells separate.

Cytokinesis Plant Cells: Cell plate forms which becomes the cell wall and divides the two cells.

Do Now Please hand in your homework in the bin. Then answer: What does asexual reproduction mean? What are some examples of asexual reproduction that you can think of?

“Both sexual and asexual reproduction involve cell division” Most unicellular organisms use cell division to reproduce through asexual reproduction. Asexual Reproduction: one organisms produces one or more new organisms that are identical to itself and that live independently of it Live independently of parent Ex. New skin cells are part of skin tissue and cannot live independently!

Asexual Reproduction: Binary Fission A form of asexual reproduction in prokaryotes. The parent organism splits in two, creating two independent daughter cells. Genetically all the same! https://www.youtube.com/watc h?v=Th4v_Q1iHfY

Asexual Reproduction: Budding Budding- Tiny Buds on organisms body! Genetic material the same! Detaches when it reaches a certain size Both Unicellular and Multicellular organisms can reproduce by budding. Ex. Unicellular- Some Yeast Multicellular - Hydra Hydra

Asexual Reproduction: Regeneration The process of new tissue growth at sites with wounds or lost limbs. Asexual Reproduction: Regeneration

Bacteria Many bacteria have a very short generation time. Some can have a new generation of cells in less than 30 min. Ex: E. Coli can double every 20 minutes. Why you get sick so fast!