Bacteria are microscopic uni-cellular organism. The cells don’t have a membrane-bounded nucleus and they also don’t have other membrane-bounded organelles.
Properties of Bacteria
  • Prokaryotic- no membrane- enclosed nucleus.
  • They have no mitochondria or chloroplasts.
  • Have a single chromosome.
1. closed circle that is of double slandered DNA
2. no associated histones

  • If there is flagella they are made of a single filament of the protein that is called flagellin.
  • Ribosomes differ in structure from eukaryotes.
  • Have a cell wall made of peptidoglycan.
  • Bacteria don’t have mitosis.
  • They mostly use asexual reproduction.
  • They also don’t have meiosis.
  • Many bacteria form a spore when their food supply begins to run low, most of the water is removed from the spore and metabolism stops.
Classification
· Shape
1. bacilli- rod shaped
2. cocci- spherical
3. spirilla- curved walls


· ability to create spores
· form of energy production
· nutritial requirement
· reaction to the gram stain

The gram stain- named after the 19th century Danish bacteriologist who developed it.


· The bacterial cells are first tainted with a purple dye called crystal violet.
· The preparation is treated with alcohol or acetone.
· It washes the stain out of Gram- negative cells.
· Bacteria that aren’t decolorized by the alcohol or acetone are Gram-positive. \
Mitochondria and Chloroplasts

There is a lot of evidence that chloroplasts and mitochondria evolved from once free-living bacteria.


· Alpha- proteobacteria like the rickettsias for mitochondria.
· cyanobacteria for chloroplasts.


Videos

http://www.youtube.com/watch?v=p3jHBOibin8&feature=fvw

http://www.youtube.com/watch?v=41aqxcxsX2w