The Importance of Cell Division

Why would a cell want to divide?

Purpose of Cell Division Three purposes of cell division: Reproduction Repair Growth

Cell Division For Reproduction All cells use cell division to reproduce Each division results in two new cells

Involves one parent cell Types of Cell Division Asexual Reproduction Involves one parent cell Produces two identical daughter cells each with a complete set of identical genetic information

Examples of Asexual Reproduction Hydra and Planaria

Types of Cell Division Sexual Reproduction Involves two parent cells Each parent provides half the DNA found in the daughter cells. Produces offspring with characteristics from both parents.

Cell Division for Repair Replacement of damaged cells – cuts, broken bones. Production of new red blood cells.

Cell Division for Repair Millions of skin cells are shed and replaced daily.

Cell Division for Growth Growth is a matter of increasing the number of cells that are present Cells getting bigger doesn’t work

Cell Division for Growth Cells all need energy, nutrients, water and gases to grow. Chemicals need to be in solution to be used. Cells need water to use chemicals and get rid of waste.

Cell Division for Growth

Cell Division for Growth Chemicals enter a cell across the cell membrane, and travel through the cell to where it is used. Movement of chemicals is called DIFFUSION

Cell Division for Growth Water enters a cell across the cell membrane in a process called OSMOSIS.

…why do chemical particles move? Osmosis/Diffusion …why do chemical particles move? Chemicals move from an area of high concentration to low concentration. Water moves to where the solution is more concentrated.

Particles will diffuse through the first cell and into the next cell. Osmosis/Diffusion Particles will diffuse through the first cell and into the next cell.

Osmosis/Diffusion Concentration is the amount of a substance present in a given volume of water.

Vocabulary you need to become familiar with! Asexual Reproduction Sexual Reproduction Diffusion Osmosis Concentration

Homework! Page 37 Questions #1 - 6

Microscopes Let’s read the rules! Identify parts and functions Use Pg 605

Drawing Biological Diagrams Draw a Biological diagram for the following image Total Mag = Ocular Mag x Objective Mag x 100%

Switch your Work

Did he/she? Name (first and last), date and teacher's name in top right hand corner Title is appropriate Title is underlined and centred in middle of page Pencil is used for diagram and labels Clean, thick, sharp lines; stippling is used for dark areas Diagram takes up at least ½ of the page Accurate drawing (draws what is seen)

Records total magnification; is correctly calculated Total magnification is recorded under drawing Labels are printed to the right of the diagram Labels are aligned under each other Label lines are drawn with a ruler and do not cross each other All structures are labeled correctly