Chapter 1 in “C” section of book.

 Our living structure is determined by the amazing variety of ways in which cells are put together.

 Wait—what is a function? A function is the processe(s) that enable an organism to stay alive and reproduce.  1. Obtaining oxygen  2. Getting rid of wastes  3. Obtaining food  4. Growing.  Cells are involved in all of the above functions and many more.

 Our digestive system will  absorb food. The food  provides our body with energy and materials  for growth.

 Until the 1600’s no one knew about cells because we could not see them.  About 1590 microscopes were invented.  Robert Hooke, an English scientist and inventor built a compound microscope. He looked at a thin slice of cork. He thought the empty spaces in the cork looked like rectangular rooms and called them “cells” which means small rooms.

 He began using a microscope about the same time as Robert Hook. He would observe drops of lake water, scrapings from teeth and gums, water from rain gutters, and such items. He found many one-celled organisms living in these substances—much like you found in the pond water.  He called them “ animalcules” which means “little animals”.

 Schleiden, Schwann, and Virchow were German scientists that gave us very important contributions about cells.  1838-Matthias Schleiden concluded that all plants are made of cells.

 The cell theory is a widely accepted explanation of the relationship between cells and living things.  The cell theory states:  1. All living things are composed of cells.  2. Cells are the basic units of structure and function in living things.  3. All cells are produced from other cells.

 Because we have the ability to look at cells and bacteria and even virus through microscopes, all the knowledge of the early scientists has become better for us today.

 Microscopes combine two properties to work:  Magnification and resolution  Magnification makes things look larger than they are. The lenses in light microscopes magnify an object by bending the light that passes through them. The lens is curved and the light bends inward which makes the things appear larger than they are.

 This type of microscope uses more than one lens. The light passes through the specimen and then through two lenses.  The first lens will magnify and the second lens, near the eye will also magnify. That is how you get the 10 power X the 40 power lens which will equal a 400 times larger image.  This is the type of microscope we use in lab.

 This is the ability to see the individual parts of an object. Another term would be “sharpness” of the object and you could tell different parts from each other.

 Since 1930’s scientists developed electron microscopes. They used a beam of electrons instead of light to produce a magnified image.  The images are better and they can look at much smaller organisms that what can be seen with a light microscope. The resolution is also much better.