Tools used in Biological Research

Any tool used to magnify the image of a close object. Microscopes Any 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 Microscope AKA 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 Microscope Different from light microscopes : Use beams of electrons rather than beams of light. Gives High Magnification and Excellent Resolution Two 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 mixtures of substances for analysis Centrifuge Chromatography Electrophoresis

Centrifuge Used to spin a solution to separate the particles based on their density. Heavy to the bottom, light on top

Chromatography The 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

Electrophoresis A 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 Techniques Indicators: -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.

Used in medicine and research to help investigate problems. Diagnostic Tools Used in medicine and research to help investigate problems.

Magnetic Resonance Imaging

Positron Emission Tomography PET