Have your body changed in the pass six months?

Tall/Weight

Are you taller?

Did your hair grow?

Clip your toenails?

Broken a bone recently?

Wound – how does your body repair itself?

What do the following examples have in common?

• Scraping your knee and the cut healing.• Growing taller.• Hair growing continuously if not cut.• Finger and toenails growing continuously if not

cut.

How do these examples relate to the cell theory?

What are the basic parts of the cell theory?

• All living things are composed of cells.• Cells are the basic unit of life.• All cells come from pre-existing cells.

How do our cells produce new cells?Mitosis

MitosisDefinition:To create two identical daughter cells

that are genetically identical to the parent cells

Q: What kind of cells would perform mitosis?

Somatic cells (all body cells except gamete cells)Gamete: sex cell (ex: sperm & egg)

Acronym for MITOSIS

IPMAT (C)InterphaseProphase

MetaphaseAnaphaseTelophase

(Cytokinesis)

Watch the video on the Cell Cycle and make observations about what you see

on your handout using this drawing

Interphase

Interphase

•Interphase is not part of mitosis•It involves creation of new organelles (G1), replication of chromosome (S), and synthesis of proteins necessary for mitosis (G2).•Chromosomes appears as thread-like structures called chromatin.

Chromosome Count:G1- 23 pairs/ 46 totalS – 46 pairs/92 totalG2- 46 pairs/ 92 total

Prophase

Prophase• Chromatids form (replicated chromosomes condense and become visible in a light microscope)• The nucleolus disappears• Paired centrioles (centrosomes) move opposite ends of the cell• Spindle forms• Asters (short microtubules radiating from centrioles) form

A closer view of Chromatids

Metaphase

Metaphase• Sister chromatids line up at the middle of the spindle (equator)• Each centromere attaches itself to the spindle fiber• At the end of metaphase, the centromeres divide.

Chromosome Count:Beginning- 46 pairs/92 total

Anaphase

AnaphaseCentromere splits and homologus chromosomes

go to opposite poles of cell

Anaphase• The separated chromatids, now called chromosomes are pulled apart towards the opposite poles by the contraction of spindle fibres• Anaphase is completed when chromosomes arrive at the poles

Telophase

Telophase•Chromosomes reach the poles of the cell and cannot be seen clearly•The spindle fibers disappear and centrioles replicate•Nuclear membrane re-forms around chromosomes and the nucleolus reappears in each nucleus•Telophase may lead straight into cytokinesis

Chromosome Count:Each new cell has 23 pairs/ 46 total

Cytokinesis• Cytokinesis is the separation of the parent cell’s cytoplasm at the end of a mitosis

• Cytokinesis in animal and plant cells are different• In animal cell:• CLEAVAGE FURROW (animal cells)• CELL PLATE (plant cells)

Chromosome Count:Each new cell has 23 pairs/ 46 total

GROUP ACTIVITY: IDENTIFY THE PHASE OF MITOSIS SHOWN IN THE FOLLOWING SLIDES

Answer: Prophase

Answer: Anaphase

Answer: Interphase

Answer: Telophase/Cytokinesis

Answer: Metaphase

Activity 1: Mitosis in ActionWatch the videos on mitosis in animal and plant cells.

Answer the following questions after watching:1. What did you notice about how the chromosomes

changes from interphase to prophase? Observe their characteristics.

2. What did you notice happening during metaphase?3. What did you notice happening to the cell during

anaphase?4. What happened to the cell during

telophase/cytokinesis?

Activity 2: Mitosis Chart

• Make a chart that details the stages of mitosis including interphase, prophase, metaphase, anaphase, and telophase/cytokinesis.

• Include drawings for each stage. • Label key parts of the cell.• Include the # of chromosomes present during

interphase, anaphase, and telophase/cytokinesis.