3. The Discovery of Cells In 1665 Robert Hooke looked at cork under the microscope and described what he saw as “tiny rooms” or “cells”

4. Cell theoryCell theory includes three principles. Getty Images

5. Concept #1- A polar bear is made up of many cells! Concept #3- All polar bears cell came from a single living cell. They divide and they grow to replace old dead cells! Concept #2- Different cells in a polar bears body does different jobs (functions). Example: Fat cells provide insulation and energy, while red blood cells carry oxygen.

6. The main ingredient in any cell is water. A water molecule has two areas: The negative (–) end can attract the positive part of another substance. The positive (+) end can attract the negative part of another substance. Basic Cell Substances

7. All cells have: 1.Cell membrane –a flexible covering that protects the inside of a cell –controls movement of materials in & out of the cell

8. All cells have: 2. Hereditary material- DNA A nucleic acid, such as DNA, contains the genetic information for a cell.

9. All cells have: 3. Cytoplasm- Clear, thick, gel-like fluid that contains most of the cell’s water, salts, other molecules, and all organelles *It is constantly moving

10. All cells have: 4. Organelles- tiny membrane- surrounded structures inside the cell that carry out specific functions. –They enable the cell to live, grow, and reproduce