Ch 7.1: Cellular Theory

Microscopes: Compound Light Microscope Most common microscopes Light passes through the object in order to see it Example: Plant cells / Animal cells Since the light scatters when it passes through the object, you can only see objects clearly up to 1000 times Since most cells are glass-like, you have to use stains to be able to see the cells Certain stains will stain specific organelles / cells certain color Example: Methyl Blue  acidic cell parts blue Example: Iodine  carbs in plants and animals brown and glycogen red

Microscopes: Electron Microscope Focus beams of electrons using magnetic fields to see even smaller cells Examples: RNA / DNA Two Types: Transmission Electron Microscope (TEM): looking through a thin-sliced sample Scanning Electron Microscope (SEM): scans over the surface of the species They can be used to see cells that are 1 billionth of a meter in size Only used to see the cells of non living thing because electrons are easily scattered by molecules in the air; so, the sample must be placed in a vaccum and need to be chemically preserved

Cell Theory Cells: the most basic unit of living things Robert Hooke found living cells in the cork of plants Anton van Leeuwenhoek found living cells in a sample of water, as well as bacteria in his own mouth Cell Theory All living things are made up of cells Cells are the basic unit of structure and function in living cells New cells come from existing cells

Cell Types: Prokaryote Smaller and Simpler Has an outer cell membrane DNA is NOT enclosed in a nucleus They must do the 9 things to be considered living Example: bacteria

Cell Types: Eukaryote Larger and more complex Has an outer cell membrane DNA is enclosed in a nucleus Has cellular membranes that are specialized for certain functions Some are unicellular (uni- = one) → protists Some are multicellular (multi- = more than one) → plants and animals

Plant Cell Animal Cell