Mitosis animation:

 Influenced by  Function (ex/eggs), Surface Area, Volume, and Mass

 Must be large enough to have enough DNA for cell to function  Can not be too large- metabolic processes need to be to occur  Surface area to volume ratio decreases Everything passes through plasma membrane!

 If a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome).  Why is this important? So every cell has the correct amount of DNA!  ASEXUAL RPRODUCTION!  Reproduction from a single parent  Inherit genes of that parent only – CLONING!!  Ex/ bacteria

 MITosis takes the cell and Makes It Two (diploid)  From the cell’s point of view:  mITosis results in Identical Twins Clyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New York

MAJOR EVENTS IN MITOSIS

 Mitosis animations:

VOCABULARY  Chromosome  Chromosome = Carries genes (DNA) from 1 cell to another during cell division. Contain DNA from both parents  Humans have 46 Chromosomes!  23 sex chromosomes ( Just ½ the #)

Diploid Diploid = Two copies of each chromosome, one paternal, one maternal Haploid: Haploid: 1 copy of each chromosome (sex cells: must combine with other sex cells)

DNA is replicated along with organelles and other cellular components and the cell prepares for division. DNA is replicated so the daughter cells have the correct number of chromosomes

THE CELL CYCLE: INTERPHASE 3 stages Series of events that take place as they grow and divide

Animal cellPlant cell Photographs from: Longest Phase

The DNA recoils, and the chromosomes condense (visible); the nuclear membrane disappears, and the mitotic spindles begin to form.

Photographs from: Animal cell Plant cell

The chromosomes line up the middle of the cell with the help of spindle fibers attached to the centromere of each replicated chromosome.

Animal cellPlant cell Photographs from:

The chromosomes split in the middle and the sister chromatids are pulled by the spindle fibers to opposite poles of the cell. Identical sets of chromosomes

Animal cell Plant cell Photographs from:

The chromosomes, along with the cytoplasm and its organelles and membranes are divided into 2 portions. This diagram shows the end of telophase.

Animal cellPlant cell Photographs from:

The actual splitting of the daughter cells into two separate cells is called cytokinesis -Occurs differently in both plant and animal Cells.

 2 diploid cells  (start with diploid, end with diploid!)  Genetically identical cells (clones)  In somatic cells, NOT gametes  Only 1 division occurred

Interphase Prophase Metaphase Anaphase Telophase Cytokinesis IPMATC I Play Music At The Curb Julie Camp’s mitosis power point -

 Meiosis animation:

 Diploid  Haploid  Germ cell (gametes)  Somatic cell  Interphase  Prophase  Metaphase  Anaphase  Telophase  Cytokinesis

MEIOSIS Fusion of two gametes, sex cells, (1 form each parent) to produce a single zygote. Sexual reproduction: Introduces greater genetic variation

Same as in Mitosis: -Cell cycle -G1, S, G2 stages

-Chromosomes are visible, -Nuclear envelope disappears. -Centrioles begin to form spindle fibers (same as mitosis) DIFFERENCE: **Exchange of DNA occurs- “crossing over”. Chromosomes double** LONGEST PHASE!!!

 When DNA is exchanged it contributes to genetic variation.  Crossing over occurs in different locations in each cell

-Nuclear membrane dissolves -The homologous chromosomes attach to the spindle fibers. -Lined up in center *Mitosis difference 

The chromosomes (not chromatids) separate and move to opposite ends of the cell. -Mitosis difference 

The cell begins to divide into two daughter diploid cells. **Each daughter cell can get any combination of maternal and paternal chromosomes. Mitosis difference 

 No new chromosome replication occurs in Meiosis II  2 diploid cells (from meiosis 1) divide again  **No Interphase II

The cell has divided into two daughter cells. Prophase II is identical to prophase of mitosis except that there is half the amount of chromosomes- nuclear membrane dissolves

As in Meiosis I, the chromosomes line up on the spindle fibers.

The two cells each begin to divide. As in Meiosis I, the chromosomes move to opposite ends of each cell.

As in Mitosis, the cells divide. *4 haploid cells are made!

 Diploid to haploid cells  4 haploid cells are made  Gametes (sex cells)  Genetically different cells, unique!  Sex cells have 23 chromosomes