Cell Theory & Microscope Notes

Primary Learning Objectives 1. To know the three parts of the cell theory and the scientists who help to develop it. 2. To know the functions of the microscope.

Robert Hooke 1635-1703 In 1665 Hooke was the first person to use the term CELLS when he looked at thin slices of cork.

Hooke’s Drawing of Cells Cork Cells (Stained) Hooke’s Drawing of Cells

Although best known as the leading British botanist to collect in Australia during the first half of the 19th century, In 1838 he was the first to note that all plant cells contained a small, round mass that he called the nucleus. Robert Brown 1773-1858

Matthias Schleiden (1804-1881) German Botanist who, in 1838, put forward the idea that all plants are made of cells.

Theodor Schwann 1810-1882 The following year in 1839 German biologist Theodor Schwann proposed that all animals were also made of cells.

German Doctor who in 1855 stated that all cells come from other living cells. Rudolph Virchow 1821–1902

The Ideas of these five scientists were put together to form THE CELL THEORY Robert Brown Robert Hooke Matthias Schleiden Theodor Schwann Rudolph Virchow

THE CELL THEORY Part One 1. All living things are made up of one or more cells.

THE CELL THEORY Part Two 2. The cell is the smallest form of life. Bacterial cells are between 1 & 10 micrometers in size.

THE CELL THEORY Part Three 3. All cells come from other living cells.

Parts of the Microscope

1. Eyepiece: contains the lens that you look through.

2. Coarse Focus Adjustment: Controls the movement of the body tube, used only for large adjustments in focusing and to bring objects into view under low power only.

3. Fine Focus Adjustment: Controls movement of body tube, used to sharply focus image after coarse adjustment has been used.

4. Low Power Objective Lens: used first to bring object into view.

5. Arm: supports the body tube 5. Arm: supports the body tube. Along with the base is one of the two points you should be holding when carrying a microscope.

7. Body Tube: connecting piece between the eyepiece and the objective lens.

8. Revolving Nosepiece: Contains the objective lenses and can be rotated.

9. Medium Power Objective Lens: Used only after getting object into focus under low power objective lens.

10. High Power Objective Lens: Used only after object has been focused under medium objective lens.

11. Stage Clips: Holds microscope slides in place.

12. Stage: Platform that holds slides.

13. Diaphragm: Rotates to control the amount of light that reaches eyepiece.

14. Light Source: Electrical light that directs light up to the stage.

15. Base: Supports microscope 15. Base: Supports microscope. Along with the arm is one of the two points you should be holding when carrying a microscope.

How To Focus a Microscope STEP 1: Start on Low power. Use coarse adjustment knob to bring object into view. Then use fine adjustment focus to sharpen image.

How To Focus a Microscope STEP 2: Take eye away from eyepiece and turn nosepiece to Medium Power. Use fine adjustment ONLY to focus.

How To Focus a Microscope STEP 3: Take eye away from eyepiece and turn nosepiece to High Power. Use fine adjustment ONLY to focus.

How to Calculate the Magnification Power of a Microscope Multiply the magnification power of the eyepiece (ocular lens) by the magnification power of the objective lens (Low, Medium or High). Eyepiece X Objective Lens = Total Magnification 10x X 43x = 430x

How to Prepare a Wet Mount 1. Place a drop of water on a slide. 2. Place your specimen into the water. 3. At an angle, gently place the coverslip on top of the specimen.

How to make a Wet mount Slide It is important to place the coverslip at an angle to avoid getting air bubbles trapped between the coverslip and the slide because this makes viewing your specimen more difficult.