Microscopes
Two important factors in microscopy are:
1) Magnification: an increase in the object’s apparent size compared with its actual size.
2) Resolving Power: the ability of an optical instrument to show two objects are separate.
Three types of microscopes:
1) Light Microscope (LM) M: 1000x RP 0,2 micrometer (small bacterial cell)
2) Electron Microscope (EM) uses a beam of electrons to resolve electrons, better resolving powers than light microscope M:100,000x RP 0,2 nanometer
A) Scanning Electron Microscope (SEM) Surface
B) Transmission Electron Microscope (TEM) Internal Structure
Preparing specimen for electron microscope hard, light microscope still very useful as a window on living cells.
The Two Major Categories of Cells
Prokaryotic Cells (Bacteria and Archaea) | Eukaryotic Cells (Protists, plants, fungi and animals) | Older in Evolutionary Sense | Younger in Evolutionary Sense | Smaller | Bigger | Simpler in structure | Complexer | | Have organelles, membrane-enclosed structures that perform specific functions | Nucleoid, not partitioned from the rest of cell. | Most important organelle: nucleus, double membrane, hosts most of the DNA | Circular DNA | Linear DNA |
In common:
1) All bounded by Plasma Membrane: regulates the traffic of molecules between the cell and its surroundings.
2) DNA
3) Ribosomes: tiny structures that build proteins according to instruction from the DNA
Overview of Eukaryotic Cells
Plant cells have:
1) Central vacuole
2) Cell Wall
3) Chloroplast
Animal cells have:
1) Centriole
2) Lysosome
3) Flagellum
Membrane Structure
The plasma membrane is the boundary that separates the living from its non-living environment
The plasma membrane can regulate the traffic of chemical into and out of the cell.
Plasma membrane and others composed of mostly lipids and proteins. Lipids belong to special category phospholipids: two tails (water fearing) + phosphate