1. CHAPTER 7 Cell Structure and Function Page 188 and 189

2. 7.1 LIFE IS CELLULAR  Key Questions:  What is the cell theory?  How do microscopes work?  How are prokaryotic and eukaryotic cells different?

3. EARLY MICROSCOPES  Seeing is believing  In the early 1600’s, eye glass makers discovered that they could use several lenses to magnify even the smallest objects  In 1655, Robert Hooke used an early microscope to look at a cork. He saw tiny chambers that he called cells  During the same time, Anton van Leeuenhoek used a single lens microscope to look at pond water. He saw tiny organisms everywhere!

4. THE CELL THEORY  Cells are the basic units of life.  Rudolf Virchow concluded that new cells can only be produced from old cells  The cell theory states  All living things are made up of cells  Cells are the basic units of structure and function in living things  New cells are produced from existing cells

5. EXPLORING THE CELL  Most microscopes use lenses to magnify the image of an object by focusing light or electrons.  Today’s biologist still use microscopes to explore cells. The microscopes are just much more powerful.

6. LIGHT MICROSCOPES AND CELL STAINS  A typical light microscope allows light to pass through a specimen and uses two lenses to form an image.  Light microscopes can only work to a magnification of about 1000 times.  Most cells are clear and difficult to see. Chemical stains or dyes help this problem. Some stains are so specific they can only reveal certain compounds or structures.  Fluorescence is another type of staining that gives off a particular color when viewed under certain wavelengths of light.

7. ELECTRON MICROSCOPES  Transmission electron microscopes make it possible to explore cell structures and large protein molecules. Samples must be cut very thin or the electrons can not pass through them.  Scanning electron microscopes, a pencil-like beam of electrons is scanned over the surface of a specimen. The specimens do not have to be cut and the images are stunning 3-D images.  Images of what the types of microscopes ‘see’ are on page 192

8. PROKARYOTES AND EUKARYOTES  Cells fall into two broad categories, depending on whether they contain a nucleus. The nucleus is a large membrane enclosed structure that contains genetic material in the form of DNA and controls many of the cell’s activities.

9. PROKARYOTES  Are generally smaller and simpler  Do not separate their genetic material within a nucleus  Despite being simple, they are a living thing and carry out life processes

10. EUKARYOTES  Generally larger and more complex than prokaryotic cells.  The nucleus separates the genetic material from the rest of the cell.  Come in a great variety.  Some live solitary, unicellular lives  Others form large, multicellular organisms and have specific functions.

11. 7.1 ASSESSMENT  Page 194 Questions 1-5. Turn in by placing it in the folder at lab station A