Chapter 1.4 Tools and Procedures

A Common Measurement System Most scientists use the metric system when collecting data and performing experiments. Metric System – is a decimal system of measurement based on certain physical standards and scaled on multiples of 10

Problems: 300 1. 3 meters = _____ centimeters 2. 40 liters = _____ dekaliters 3. 600 milligrams = _____ grams 4. 5 kilometers = ______ hectometers 5. 70 centimeters = _______ meters 6. 900 deciliters= ______ dekaliters 7. John's pet python measured 600 centimeters long. How many meters long was the snake? 8. Faith weighed 5 kilograms at birth. How many grams did she weigh? 9. Jessica drank 4 liters of tea today. How many deciliters did she drink? 4 0.6 50 0.7 9 6m 500g 40dL

Analyzing Biological Data The simplest way to collect data is to record the data in a table and then make a graph. Computers are good tools to figure out data or to make models. Computers are necessary when comes to collecting data by satellite and recording results at different intervals. Analyses of satellite data are used to make predictions about complex phenomena such as global climate change.

What is a microscope? Micro- ‘small’ Scope- ‘see, to look at’ Microscope – a device that produces magnified images of structures that are too small to see with the unaided eye

Compound microscope Electron microscope

2 kinds of microscopes: Compound light microscope – a microscope that allows light to pass through a specimen and uses two lenses to form an image Electron microscope – a microscope that forms an image by focusing beams of electrons onto a specimen. It’s very precise device and can form images of objects 1000 times smaller than those visible under a light microscope.

Functions of the two microscopes: Compound light microscope – can used to observe dead organisms, or tiny living organisms or cells Electron microscope – can be used to observe only dead and preserved cells (it must be completely dried out to be placed under electron microscope)

Laboratory Techniques Cell culture – group of cells grown in a nutrient solution from a single original cell. It’s usually used for growing different bacteria on sugar medium (usually agar). Petri dish with bacterial cultures

Cell fractionation Cell fractionation – technique in which cells are broken into pieces in a special blender and then the broken cell bits are added to a liquid and centrifuged. Spinning causes the cell parts to separate, with the most dense parts settling near the bottom and the least dense parts rising toward the top.

Cell Fractionation

1.4 Section Assessment 1. Why do scientists use a common system of measurements?

2. What is the difference in the way light microscopes and electron microscopes produce images?

3. Describe the techniques and purpose of cell fractionation.

4. What types of objects can be studied with a light microscope 4. What types of objects can be studied with a light microscope? What types can be studied with an electron microscope?

5. It has been said that many great discoveries lie in wait for the tools needed to make them. What does this statement mean to you? If possible, include an example in your answer.