Tools usedin Biological

Research

MicroscopesAny tool used to

magnify the image of a close object.

Light Microscopes

All use rays of light, either transmitted through a thin slice or section or bounced off the surface of a specimen.

Dissecting MicroscopeAKA

Stereomicroscope

• Light source above stage – Light bounces off of specimen.

• Can be used with opaque specimens.

• Two oculae allow for binocular, 3-D image.

• No image “flip.”

Phase Contrast Microscope

• Uses polarized light to give good contrast.

• No stains necessary• Used on clear specimens• Can view living

specimens.

Electron MicroscopeDifferent from light microscopes : Use beams of electrons rather

than beams of light.

Gives High Magnification andExcellent ResolutionTwo Types:

Transmission aka TEM : electron beams pass through the specimen

Scanning aka SEM : electron beams bounce off of the specimen

TEM

SEM

Scanning Electron

Micrographs

What are these?

How does a person eat an elephant?

• One bite at a time• Science is often reductionist aka empirical.• Complex problems can be understood by

breaking them down into all of the parts and trying to understand each individual part.

• Put the understood parts together and you come closer to understanding the whole problem.

Picture: http://commons.wikimedia.org/wiki/File:African_Elephant_8.jpg

Separation Techniques

These separate mixturesof substances for analysis

1. Centrifuge

2. Chromatography

3. Electrophoresis

Centrifuge

Used to spin a solution to separate the particles based on their density.

Heavy to the bottom, light on top

ChromatographyThe process of separating chemicals based on their molecular size by using

special filter paper.

A few drops of different inks at the bottom produced these bands of color showing what colors make up the ink

ElectrophoresisA process that is used to separate pieces of

DNA by placing the DNA in a special gel and adding electricity.

First the strand of DNA is cut into pieces by special chemicals called Restriction Enzymes

Then the pieces are loaded into the gel

Other Tools and TechniquesIndicators:

-Compounds that show chemical properties, usually by a color change.

-”Low Tech”

-examples: pH paper, pool water test kits.

Image from: http://wikimediafoundation.org/wiki/File:PH_indicator_paper.jpg

Tissue Cultures• Growing tissue

outside the body• Skin is grown

outside the body to help burn victims

• One day many organs may be grown for transplant

• Ethical alternative to animal testing

Micro-Dissection

Using very small tools to dissect objects as small as

individual cells

This technique is used when cloning cells or in-vitro

fertilization.

Diagnostic ToolsUsed in medicine and

research to help investigate problems.

Magnetic Resonance Imaging

Positron Emission Tomography

PET