• Identify and describe the main phases of the cell cycle

• Identify what form DNA is in during dif ferent stages of the cell cycle

• Describe 3 key events during interphase

• Identify and describe 4 main phases of mitosis

• Compare cytokinesis in plant and animals cells

5A: CELL CYCLE &

5B: MITOSIS

The life of a cell is described as the cell cycle.

Divided into three stages:

INTERPHASE: Cells carry out normal functions

MITOSIS: Duplication of genetic material and division of the nucleus

CYTOKINESIS: Cell with 2 nuclei splits to form two identical daughter cells.

THE CELL CYCLE

Longest stage in the cell cycle

During this phase DNA is in the form of chromatin

Divided into three parts

1. Growth and Preparation: Cell increases in size while performing its

usual functions

1. DNA Replication: DNA replicates making an exact copy of itself

1. Continued Growth and Preparation: Cell continues to grow and

makes copies of its organelles

INTERPHASE

INTERPHASE – DNA REPLICATION

Shortest stage in the cell cycle

Contents of the nucleus divide resulting in two daughter

nuclei that are identical to the original parent cell

MITOSIS

Important structures:

Spindle Fibers: Protein structures that move chromosomes during

mitosis

Centrioles (Animal cells only): Organelles that control the spindle

fibers. *add label to animal cell diagram

MITOSIS

Mitosis is divided into 4 stages (PMAT)

1. Prophase (early prophase & late prophase)

2. Metaphase

3. Anaphase

4. Telophase

MITOSIS

Early Prophase

Duplicated chromosomes

condense into X-shape

Nucleolus disappears

Spindle fibers start to form

and spread across the cell

Centrioles move to opposite

ends of the cell

Late Prophase

Spindle fibers complete

forming

Spindle fibers attach to

chromosomes at the

centromere

Nuclear membrane

disappears

MITOSIS - PROPHASE

Spindle fibers pull chromosomes into a line across the

metaphase plate at the center of the cell

MITOSIS - METAPHASE

Spindle fibers contract and shorten to separate sister

chromatids and pull to opposite ends of the cell

Once separated, sister chromatids are now considered

daughter chromosomes

MITOSIS - ANAPHASE

Final stage of mitosis

A complete set of chromosomes is at each end of the cell

Nuclear membranes form around each set of chromosomes

Nucleolus reappears

Spindle fibers disappear

There are two nuclei in one cell

MITOSIS - TELOPHASE

Final stage of the cell cycle

Cell with two nuclei splits into two daughter cells

New cells are identical to each other and to the parent cell

Cytokinesis is dif ferent in plant and animal cells due to the

presence of a cell wall in plants.

Animal cell: Cell membrane pinches together to separate two halves

Plant cell: Cell plate forms along center of the cell

CYTOKINESIS

MITOSIS: http://youtu.be/aDAw2Zg4IgE