1 4 Tools and Procedures Objectives 1 What

1 -4 Tools and Procedures Objectives: 1) What measurement system do most scientists use? 2) How are light microscopes and electron microscopes similar? How are they different?

A Common Measurement System § Scientists use a common measuring system called the International System of Units, or SI. § Most use the metric system § Metric system: multiples of 10 § Centi-100, milli-1000, kilo-1000

Analyzing Biological Data § Often trying to find out whether certain factors changed or remained the same § Record the data in a table § Then make a graph § Can make a pattern much easier to recognize and understand

Analyzing Biological Data Cont’d § Biologists have lots of data to analyze § Use computers § Help determine § The structure of molecules § DNA molecules § Gathering data by satellite § Analyzing the data § Presenting the results

Quick Question § How can a graph help biologists analyze data?

Quick Answer § A graph of collected data can make a pattern much easier to recognize and understand.

Microscopes § Microscopes: devices that produce magnified images of structures that are too small to see with the unaided eye § 2 Kinds § Light microsopes: make magnified images by focusing visible light rays § Electron microscopes: makes magnified images by focusing beams of electrons

Microscopes Cont’d § 2 problems for microscope makes § How large can we make the image while still keeping it in focus?

Light Microscopes § Most commonly used § Can produce images clearly up to 1000 x’s § Compound light microscopes: allow light to pass through the specimen and use 2 lenses to form an image § Ways to make the light microscope more effective § Chemical stains § Fluorescent dyes

Electron Microscopes § Electron microscopes: use beams of electrons to produce images § Can make images 1000 x’s more detailed than light microscopes

Electron Microscopes Cont’d § 2 Main types § Transmission electron microscopes (TEMs): shine a beam of electrons through a thin specimen § Details inside § Scanning electron microscopes (SEMs): shines a beam of electrons back and forth across the surface § 3 D images

Laboratory Techniques § 2 common laboratory techniques § Cell culturing § Cell fractionation

Cell Cultures § Cell culture: § Place a single cell into a dish containing a nutrient solution § Reproduces cells § Used to test cells

Cell Fractionation § Cell fractionation: to separate the different cell parts § Cells are § § § Broken into pieces Added to a liquid Placed in a tube Put in a centrifuge Spun around Cell parts separate

Quick Question § What is a cell culture?

Quick Answer § A group of cells that develops from a single cell placed into a dish containing nutrient solution

Working Safely in Biology § Laboratory Safety Rules § Make sure clothing and/or will not disturb the experiment § Tie hair back § Read all directions for the experiment § Follow directions exactly § ASK QUESTIONS! § Tell the teacher if there accidents § Wear goggles as instructed § Keep a clean work area § Do not eat or drink in the laboratory § Cut away from you § Clean work area and put everything away as instructed § Wash your hands with soap

Exit Ticket § Answer the following question. § Use complete sentences. § You may NOT use your book. You MAY use your notes. § This is a quiz grade. 1) What measurement system do most scientists use? 2) How are light microscopes and electron microscopes similar? How are they different?