CELLULAR HISTORY

A. Cellular Scientists Knowledge of cells originated from English scientist Robert Hooke in 1665 Studied thin sections of cork and saw boxlike cavities he called “cells” Robert Hooke

Water flea daphnia found in pond water Dutch scientist Antony van Leeuwenhoek examined pond water in 1676 observed “animalcules” or tiny animals Were single-celled amoeba, paramecium, and other water-borne pathogens Water flea daphnia found in pond water Anton van Leeuwenhoek

Matthias Schleiden in 1838 studied plants cells make up every part of plant – stems, roots, leaves, flowers Matthias Schleiden

Theodor Schwann in 1839 viewed cartilage tissue cells animals are also made out of cells Published theory that cells are basic unit of life Theodor Schwann

Rudolf Virchow used work of Schwann and Schleiden to advance cell theory in 1858 1821-1902

Apple cells Cell theory All living things are made of one or more cells Cells are basic units of structure and function in organisms All cells arise from pre-existing cells Apple cells

Staphylococcus aureus living organisms may consist of one cell (bacteria) or many cells (plants and animals) that act as a unit or in coordination with each other Elodea plant Staphylococcus aureus

B. MICROSCOPE STRUCTURE Microscope: instrument used to magnify very small objects 9 1 2 10 3-5 11 6 12 7 13 8 14

Microscope Parts Function Arm Connects to base and supports microscope head, also used to carry the microscope. Base Bottom of microscope, supports it and houses light source Body tube Holds eyepiece in place above objective lens Course adjustment Focuses microscope by moving stage up and down in large increments Diaphragm Controls amount of light reaching specimen, located above light source and below stage Fine adjustment Sharpens focus of microscope by moving stage up and down in slight increments Light source Low voltage, halogen bulb for microscope, typically located in base

Microscope Parts Function Objectives Primary optical lenses on a microscope that magnify image Scanning 4X – used to locate specimen Low power 10X – used to locate specific area on specimen High power 40X – used to magnify specific area on specimen Ocular lens (eyepiece) 10X Lens at top of microscope that eye looks through Revolving nosepiece Houses objectives mounted on a rotating turret so different objectives can be conveniently selected Stage Where specimen to be viewed is placed Stage clips Holds the slide in place

Accessories Function Cover slip Square piece of glass or plastic to hold specimen on slide Forceps Type of tweezers used to grasp specimen Slide Piece of rectangular glass on which specimen is placed; held by stage clips Wet mount Setting specimen on slide, covering with a drop of water to stabilize specimen

QUIZ – can you name all the parts?

C. MAGNIFICATION Magnification of objective is not total magnification – must consider power of ocular lens, too Multiply ocular lens by objective lens for correct magnification Ex: ocular lens has magnification of 4X. If objective lens is 40X, what is total magnification? 4 x 40 = 160X Ex: ocular lens has magnification of 10X. If objective lens is 100X, what is total magnification? 10 x 100 = 1,000X