Do Now 1.31Objectives:

1. Be able to draw and describe what happens during each stage of mitosis.

2. Be able to define cytokinesis, and describe how it is different in plant and animal cells.

Task:Draw the chromosomes of a cell with a diploid chromosome number of 6 during the G1 phase of

the cell cycle.

Mitosis

• Mitosis is the process of a cell making two identical “daughter” cells.

Mitosis and the Cell Cycle

• The cell cycle is sometimes simplified into just two stages:– Interphase: the parts of the cell cycle when the

cell is not actively dividing. Includes G1,S, and G2– Mitosis: the process of nuclear division

(chromosomes separating to form two new nuclei)

Foldables Part Deux

• Add interphase to the outside of your foldable notes

G1 S G2 M I N T E R P H A S E

Add the 4 Stages of Mitosis

• Prophase• Metaphase• Anaphase• Telophase

G1 S G2 M

P M A T I N T E R P H A S E MP A T

M I T O S I S

What Happens During Each Stage of Mitosis

Chromosomes appear; nucleus disintegrates

Chromosomes line up in middle of cell

Chromosomes move apart

Chromosomes relax, new nuclei begin forming

Prophase: Chromosomes become visible and the nucleus disintegrates

Metaphase: Chromosomes Line Up in the Middle of the Cell

Anaphase: Chromosomes Move Apart

Note: it is at this stage that the two chromatids of each chromosome are pulled apart.Now, each chromatid from the old chromosome is called a chromosome

Telophase: Chromosomes uncoil, new nuclei develop

What pulls the chromatids apart? Spindle fibers attached to centrioles

Centrioles

PROTEINS DO IT ALL

Remember that proteins do almost all of the “work” a cell does.

PROTEINS connect the spindle fibers to centromeres

PROTEINS are what the centromeres, spindle fibers, and centrioles are made of

PROTEINS are what move the chromosomes through the cell

PROTEINS are what the DNA of a chromosome are coiled around

Mitosis vs. Cytokinesis

• Mitosis specifically refers to the division of a cell’s nucleus.

• Cytokinesis is the process of the cell’s cytoplasm dividing. It begins during telophase

Cytokinesis in Animal and Plant Cells• In animal

cells (and other cells without cell walls, a cleavage furrow develops.

• In plant cells a new cell wall is built. It is called a cell plate while under construction

Homework

• Read pp. 150-151• Answer SR #3 & 5 on p. 151