1-4 Tools and Procedures Key Concepts: Vocabulary: What measurement system do most scientists use? How are light microscopes and electron microscopes similar? How are they different? Vocabulary: Metric system Microscope Compound light microscope Electron microscope Cell culture Cell fractionation

Metric System Length Mass Volume Temperature Meters Grams Liters ºCelsius

UNITS! SCALE= multiples of 10 kilo hecto deka (g, m, or L) deci centi milli .001 .01 .1 1 10 100 1000

Analyzing Biological Data The simple way to record data Make a table… Then make a graph Graphs make patterns easier to recognize and understand

Organizing Data Data is organized and presented in tables, charts, and graphs. GRAPHING... Graph-visual representation of data 1) DESCRIPTIVE title 2) x and y axis labeled 3) units for both the x and y axis 4) scale is evenly and correctly spaced for data 5) legend/key when appropriate

LINE GRAPH LINE GRAPH: best for displaying data that CHANGE. Manipulated (independent) Variable: x-axis Responding (dependent) variable: y-axis

BAR GRAPHS BAR GRAPH: useful when you want to compare data for several individual items

“Water Released and Absorbed by Trees” Turn to page 25 in your books What is on the x-axis? What is on the y-axis? At what time of day is the rate of water released by leaves equal to the rate of water absorbed by the roots?

Microscopes Light Microscopes Electron Microscopes

MICROSCOPE NOTES COMPOUND LIGHT MICROSCOPE: most common scope Advantages: get higher magnification than with a dissecting scope. Drawbacks: the light comes from below so sample must be very thin so you can see Useful for viewing single cells Usually view dead things with this microscope. Limit of resolution: if you magnify beyond this point, the object will be blurry.

DISECTING MICROSCOPE: used to view dissection or small live (sleeping) animals such as fruit flies. Advantages: can view samples that are alive; large field of view Drawbacks: magnification is not as high as other microscopes.

SCANNING ELECTRON MICROSCOPE (SEM): used to see very small “stuff” Advantages: can study very small objects such as viruses and individual molecules; limit of resolution is 1000x that of a light microscope. Drawbacks: done in a vacuum, so object must be dead; also very expensive!

Face of an ant! IMAGES PINHEAD

Laboratory Techniques Cell Culture A group of cells develops from a single original cell. Cell fractionation Used to separate the different parts of a cell Cells are blended Added to a liquid and placed in a tube Centrifuge at 20,000 revolutions per minute Spinning separates the cell parts by density.

EYEPIECE COURSE ADJUSTMENT FINE ADJUSTMENT ARM LOW-POWER OBJECTIVE ARM HIGH-POWER OBJECTIVE STAGE STAGECLIPS FINE ADJUSTMENT STAGECLIPS BASE IRIS MIRROR COURSE ADJUSTMENT LAMP DIAPHRAGM