1. UNIT 1 BIOLOGY/2010 MR. EVANS EVANS.ANTHONY.G@EDUMAIL.VIC.GOV.AU 1Cells: discovery and exploration

2. Cell Theory Cells were first identified and named by Hooke in 1665. The nucleus in a cell was identified and named by Brown in 1831. The Cell Theory arose in the mid-1800s. The Cell Theory recognises that all living things are composed of one or more cells and that new cells are produced by existing cells. The life span of cells in a multicellular organism varies. The unit of measure often used in relation to cell size is the micrometre (Mm).

4. Microscope technologies Various types of microscopes can be used to examine cells. Light microscopes (LMs) reveal details about the arrangement of cells and the internal structure of cells. Compound light microscopes (CLMs) have at least two sets of lenses: objective lenses and ocular (or eyepiece) lenses.

6. Microscope technologies Cells are often stained with one or more dyes to make their various components easier to see. Phase contrast microscopes allow the study of unstained living cells. Fluorescent microscopes reveal details of chemical substances present.

8. Microscope technologies Confocal microscopes use lasers to produce a sharply in-focus image of a thin layer of a specimen. Electron microscopes use beams of electrons instead of beams of light. Transmission electron microscopes (TEMs) reveal fine detail of the internal structure of cells. Scanning electron microscopes (SEMs) reveal details of cell surfaces. Technological advances involving equipment and stains associated with microscopy continue to be developed.

9. Microscope technologies