Scientific Tools & Techniques

Why do we need Scientific Tools & Techniques?

Scientific Tools& TechniquesCompound Light MicroscopeUses lightImage appears upside down and backwards

Under Low Power field of view is larger (4 times)Under High Power field of view is smaller (4 times)

How will the f appear in the field of view of a compound microscope?

Upside Down and Backwards

FOV in Low Power:4 cells are visibleHow many cells will be visible in high power?

FOV in High Power:1 cell is visible!

Microscope Rules:Always start with low powerField of view is large and brightHelps you find specimen Use the coarse adjustment knob to focusSwitch to High Power to see detailAdjust diaphragm (light) for smaller field of viewField of view is smaller and darkerHelps see fine detailOnly use fine adjustment knob to focus

Total Magnification:Eyepiece # X Objective # = Total Magnification #What is the highest totalmagnification in thisdiagram?Answer:10 X 40 = 400x

Eyepiece 10x40x10xWhat is the total magnification under low power in the diagram?

Eyepiece 10x40x10xAnswer:10 X 10 = 100xElectron MicroscopeA major breakthrough because they can magnify 250,000 xsShows much more detail than compound light microscopesShows great detail of inner structuresEx) The inside of mitochondria in a cell!

Microdissection tools/instrumentsSpecial micro-tools (very tiny)Used to take apart cellsEx) Removing a nucleus from one cell and putting inside another cell!Used in genetic engineering

Use of StainingStaining allows for cell parts to be seenThe nucleus for example becomes more visible under the microscope when a stain is usedIodine is often used to stain cells

Centrifuge (Ultracentrifuge)Spins at high speeds to separate substances by densityHeavier particles end up in the bottom of the test tube

ChromatographySeparates colorsChromatography paper is usedEx) Plant pigments can be separated using chromatography

Gel ElectrophoresisUsed to separate bands of DNADNA bands of different sizes move at different ratesDNA bands move because of the chargeUsed in forensic investigation (CSI)Also used to determine paternity

Gel ElectrophoresisHow do you know these samples are from different people?Whats responsible for the movement of DNA?

Which two species of bear are most similar?How do you know?

Which direction should the slide be moved to center the cell?

The diagram below shows the letter h under low power, which diagram shows the high power field of view?

1.2.3.4.How many micrometers in diameter does each cell measure?

How many millimeters in diameter does each cell measure?

In which direction should the slide be moved to center the cell?

Name 2 unsafe practices shown below.

Which lab technique was used to separate the substances in the test tube?