2. Bacteria

AIDS, Tuberculosis, Malaria

• bacteria
• eucaria
• archea

• smaller
• lacks nucleus an other membrane bound organelles

0.2-2um

• bacillus - rod
• coccus - spherical
• spirllum - spiral
• spirochaeta - corkscrew
• vibrio - comma

species with multiple shapes

large mass of bacteria descene from a single bacterium

entire set of chemical reactions whih maintain life in a cell

• phototrophs - energy from sunlight
• lithotrophs - energy from inorganic compounds
• organo(chemo)trophs - energy from organic compounds

• carbon from CO2: -autotroph
• carbon from organic compounds: -heterotroph

chemoheterotroph: most pathogens

need oxygen for growth

need reduced oxygen level for growth

need absence of oxygen for growth

able to grow with or without oxygen

• postive and negative chemotaxis
• movement
• attachment

filament is a triple helix of proteins

• found in sprial shaped bacteria
• internal to cell wall, wrap around body
• undulating contractions of proteins causes movement

• short filament extending from surface
• function in attachment, not locomotion

• thick polysaccharide coat exterior to cell wall
• important in protecting pathogens from engulfment and digestion by white blood cells

• metabolically dormant, non-reproductive
• protects against changes in temperature and moisture
• differentiates inside of the cell
• allows survival in extremely adverse environmental conditions

• protects against rupture due to changes in osmotic pressure
• consists of peptidoglycan:
• - unique carbohydrate
• - alternating units of NAM and NAG
• - peptide crosslinks

Gram +: thick layer of peptidoglycan with teichoic acid and lipteichoic acid, no outer membrane

Gram -: thin layer of peptidoglycan, outer membrane with protein, lipopolysaccharide

gram negative loses crystal violet and becomes pink

• thin layer of peptidoglycan, outer lipid layer
• - high mycolic acid content causes cell to resist decolorization by acid
• use alternate ziehl-neelsen stain

• have single chromosome - circular
• some have plasmids
• reproduce through binary fission
• genetic diversity made by transformation, conjucation and transduction

uptake of free DNA from environment

• begins with sex pilus, special structure to make bridge between cells (often plasmid encoded)
• DNA is replicated as it is transferred
• donor retains plasmid, recipient receives copy

transfer of DNA from one cell to another by way of a bacteriophage

• metabolisms (recycling of elements in nature, bioegradation, bioremediation, endosymbionts)
• industrial uses (antibiotics, food processing, biotechnology)
• disease prevention - microflora helps prevent colonization of pathogens
• model organisms

• food spoilage
• human disease