CELL DIVISION

REVIEW OF CELL THEORY All living organisms are made of cells.

Cells are the basic unit of structure and function in all living things.

Cells come from pre-existing cells.Through both sexual and asexual

reproduction.

ASEXUAL REPRODUCTION

• Look at the picture to the left.

• The green part of the potato will grow into a second potato.

• Asexual reproduction is a type of reproduction in which a new organism is produced from one parent and has the same DNA as the parent.

• How does this happen?

PHASES OF CELL DIVISION IN ASEXUAL REPRODUCTION

Interphase - preparing for cell division by copying/replicating the DNA. This is the longest phase of the cell cycle.

Mitosis - dividing the material to be able to form 2 new cells

Cytokinesis - the actual separation or division of the cell

INTERPHASE Interphase- The first stage of the cell

cycle. Interphase happens BEFORE cell division.

Several things must occur first before the cell can divide.

The most important thing is for the DNA to be copied or replicated so that each cell has a copy of the original DNA. It is “unzipped” and base pairs match up to

create 2 strands from the original.

MITOSIS Mitosis- The stage of the cell cycle where

the cell’s nucleus actually divides into 2 new nuclei resulting in an exact copy.

Both cells now have the same genetic code. Two identical copies come from one original. Start with one cell and get two that are the

same. Mitosis is divided into four stages of its own.

Prophase Metaphase Anaphase Telophase

PHASES OF MITOSIS

WHY IS MITOSIS IMPORTANT? Cells have a limited lifespan. They

eventually can’t function and need to be replaced.

The cell cycle with mitosis is the beginning of the process by which the cells are replaced with exact clones of the old cell.

Mitosis Video Clip

WHEN MITOSIS GOES WRONG Cancer happens when a mistake is

made in mitosis. For reasons that scientists are still

trying to figure out, a cell or group of cells begins to replicate themselves very quickly.

These abnormal cells then can spread to other parts of the body.

Cancer Cell vs Normal Cell Growth

CYTOKINESIS Cytokinesis - the last stage of the cell

division cycle.The cell membrane pinches in around the

middle of the cell. The cell splits in two daughter cells. Each daughter cell ends up with an identical

set of chromosomes and about half of the organelles.

At the end of cytokinesis, each new cell enters interphase and the cycle starts over.

cytokinesis in plant and animal cells

HOW MUCH TIME IS SPENT IN EACH STAGE? PG. 100

ASEXUAL REPRODUCTION REVIEW A type of reproduction in which a new

organism is produced from one parent and has the same DNA or genetic material as the parent.

Making an exact copy of a cell.To allow growth and developmentTo replace old cellsTo repair damaged cellsTo create new organismsBrain Pop Asexual Reproduction

SOME TYPES OF ASEXUAL REPRODUCTION

Mitosis Cloning Budding Animal Regeneration