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Chapter 1 Section 4

Chapter 1 Section 4. Tools and Procedures. Tools play a major role in science. A common Measurement System. Most scientists use the metric system when collecting data and performing experiments.

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Chapter 1 Section 4

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  1. Chapter 1Section 4 Tools and Procedures

  2. Tools play a major role in science.

  3. A common Measurement System • Most scientists use the metric system when collecting data and performing experiments.

  4. The Metric System is a decimal system of measurement whose units are based on certain physical standards and are scaled on multiples of 10.

  5. A revised version of the original metric system is called the International System of Units, or SI.

  6. Because the metric system is based on multiples of 10, it is easy to use.

  7. Analyzing Biological Data • In science today, the amount of data being produced by biologists is so huge that no individual can look at more than a tiny fraction of it. • To make sense of the data, biologists often turn to computers.

  8. Check Point • How can a graph help biologists analyze data?

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

  10. Microscopes • Microscopes are devices that produce magnified images of structures that are too small to see with the unaided eye.

  11. Light microscopes produce magnified images by focusing visible light rays.

  12. Electron microscopes produce magnified images by focusing beams of electrons.

  13. Light Microscopes • The most commonly used microscope is the light microscope.

  14. Mid-Section Review • What is the most commonly used microscope? • What do light microscopes produce? • What are microscopes? • The metric system is based on multiples of? • What is the metric system?

  15. Compound Light Microscopes allow light to pass through the specimen and use two lenses to form an image.

  16. Electron Microscopes • Electron Microscopes focus beams of electrons on specimens.

  17. These microscopes can form images of objects 1000 times smaller than those visible under a light microscope.

  18. Biologists use two main types of electron microscopes, Transmission electron microscopes and Scanning electron microscopes.

  19. Transmission Electron Microscopes (TEMs) shine a beam of electrons through a specimen.

  20. Scanning Electron Microscopes (SEMs) run a pencil like beam of electrons back and forth across the surface of a specimen.

  21. Check Point • What are microscopes used for?

  22. SEMs produce realistic and often dramatic three dimensional images of the surfaces of objects.

  23. Cell Cultures • The cell is able to reproduce so that a group of cells, called a Cell Culture, develops from the single original cell.

  24. Cell cultures can be used to test cell responses under controlled conditions, to study interactions between cells, and to select specific cells for further study.

  25. Cell Fractionation • Biologists often use a technique known as Cell Fractionation to separate the different cell parts.

  26. Section Review • Page 28 1-5

  27. Think, Pair, Share • Figure 1-24, 1-27, and 1-28.

  28. Quiz • Compare and contrast the two main types of electron microscopes. • What is a cell culture? • What is Cell Fractionation? • What is a Compound Light Microscope? • What is the Metric System? • What multiples is the Metric System base on? • What is the purpose of a microscope?

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