Transcript Slide 1
Microscopes, Cell Theory EYEPIECE ARM OBJECTIVES STAGE COARSE FOCUS DIAPHRAGM FINE FOCUS BASE - Always carry microscope by ARM and BASE. - Always begin by finding image using COARSE FOCUS. - Use coarse focus only with LOW POWER. Otherwise, use fine focus. - Magnification = Eyepiece x Objective Ex. Eyepiece is 4x. Objective is 20x. Overall magnification equals 80x. Cell Theory Cell definition – the basic unit of structure and function for all living things. onion blood sperm and egg bacteria Cell Theory What allowed us to discover cells? Microscope http://micro.magnet.fsu.edu/primer/java/electronmicroscopy/magnify1/i ndex.html Robert Hooke; 1665; cork cells . . . I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular. . . . these pores, or cells, . . . were indeed the first microscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this. . . Cell Theory In the mid-1800’s , Cell Theory was developed which states: 1. All living things are made of cells. 2. Cells are the basic unit of structure and function. 3. All cells come from pre-existing cells. Cell Theory Two different classes of cells: 1. Eukaryotes: have a nucleus; plants and animals 2. Prokaryotes: no nucleus; bacteria Cell Theory How big are cells? http://www.cellsalive.com/howbig.htm 1. Plants and animals: 10 – 50 micrometers (millionths of a meter) 2. Bacteria: 1 - 2 micrometers or less (less than 1/10th size of plant and animal cells) Cell Theory Can some cells live on their own? Yes! http://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/stentor/t1/stentor08.html http://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/euglena/rostrifera/t1/rostrifera08.html http://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/paramecium/t1/paramecium09.html Cell Theory Cellular Organization Simple complex 1. Cell 2. Tissue 3. Organ 4. Organ System Many systems put together is an ORGANISM.