Microscope and Other Tools

One of the most important tools is the compound microscope. Used to see the microscopic world or objects too small for the naked eye. Plant cells, animal cells and bacteria cells can be observed. Used to diagnose cancer

How does it work? light passes through a specimen on the stage to form an image. It can make objects 1000 times its normal size. light

How to determine magnification: Multiply the eye piece by the objective. For example if the eye piece is 10X and the objective is 25X, your total magnification is 250X. 10 x 25 =250x 10x 25x

What is the total magnification of the following microscopes? Ocular: 10x Ocular: 15x objective: 40x objective: 100x

Parts of the microscope. 1. Ocular lens/eye piece: Contains a magnifying lens, usually 10x or 15x.

Objective lens: has three different magnifying lenses: Scanning lens: magnifies image 4X Low power: magnifies 10X C. High power: magnifies 40x

3. light source 4. diaphragm: regulates amount of light that passes up towards the eye piece.

5. Base: support microscope 6. Arm: supports body tube

7. Stage: supports slide to be observed. 8. Stage clips: Holds slide down on stage

Nosepiece: hold objectives, can be rotated. 10. Course Adjustment: moves body tube in order to focus the image.

Fine Adjustment: moves body tube slightly to sharpen image. 12. Body tube: keeps proper distance between eye piece and objectives.

F Images viewed under the light microscope are upside down and backwards This is a compound light microscope view of the letter F placed on a slide in its normal position.

Wet Mount Used for to see specimens under a microscope Step 1: Clean your slide- with filter paper Step 2: Place slide on flat surface Step 3: Place specimen in the middle of the slide with forceps Step 3: Add 1 drop of water with eyedropper *NOT TOO MUCH*

**this angle and speed eliminates air bubbles** Step 4: Holding a cover slip on the sides (see picture ), place the bottom edge along the outer side of the drop of water at a 45° angle  Step 5: Slowly lower the cover slip. **this angle and speed eliminates air bubbles** 45° https://www.youtube.com/watch?v=SPg5pfwPPu0

How to clean a wet mount slide: Over a waste paper basket and using a paper towel, wipe the coverslip and specimen into the garbage bag Rinse the slide off in sink Dry off with paper towel Return to teacher designated area

Staining Some specimens cannot be seen by themselves Staining gives more contrast Commonly used stains: Iodine (usually used on plant cells) Amber in color Methylene Blue (used on animal cells) Blue in color

Staining Technique Step 1- Prepare a wet mount slide Step 2- Collect stain with an eye dropper or pipette Step 3- Put a drop of stain on an outer edge of your cover slide.

Step 4- Place a piece of napkin or paper towel against the opposite side of your cover slip, right up against the edge. This will help draw the stain under the cover and across the specimen.

Step 5- You may need to add another drop to ensure complete coverage. Step 6- The slide is now ready for viewing https://www.youtube.com/watch?v=DJsf6nWjcA8

Other important lab techniques Chromatography Gel electrophoresis

A lab technique used to separate mixtures. Often done on paper Chromatography A lab technique used to separate mixtures. Often done on paper The chemicals separate based on density. The solvent is absorbed up the paper, separating the mixtures place on the paper by the scientist. Animation: https://www.youtube.com/watch?v=SnbXQTTHGs4 Solvent moves up paper

How paper chromatography works. Watch the water move up as it is absorbed by the paper. Separates the chemicals that make up the black dot as it moves.

Chromatography of a Leaf

2. Electrophoresis used to separate molecules such as DNA by size and charge charged molecules like DNA are placed in an electric field, they migrate toward either the positive or negative pole according to their charge .

Put DNA in the wells, Plug it in Separates based on size of molecules and charge DNA has a negative charge, so its attracted to the positive side. Smaller pieces move further. Every one’s DNA is unique. Everyone's DNA separates in a unique pattern.

Gel electrophoresis is one way to determine your baby’s momma Also used to solve crimes (DNA Fingerprinting) Animation: https://www.youtube.com/watch?v=mN5IvS96wNk

Electrophoresis pics The set up