Bacteria: : Bacteria: Evolution and Classification
Slide 2 : Review Recall that cells are either:
*Prokaryotes – have No membrane bound organelles or nucleus
*Eukaryotes – have membrane bound organelles and a nucleus
Eukaryote : Eukaryote
Prokaryote : Prokaryote
Slide 5 : General characteristics of Bacteria Prokaryotes
microscopic
Oldest organisms (existed 3.5 billion years ago)
Adapted and evolved greatly over time (result:many species, part of every environment on Earth)
Most numerous organisms
Smallest, simplest organisms
There are 6 Kingdoms of living things: : There are 6 Kingdoms of living things: Animals
Plants
Fungi
Protists
Archaebacteria
Eubacteria
Bacteria make up two kingdoms : Bacteria make up two kingdoms Archaebacteria
Eubacteria
Classification of Bacteria : Classification of Bacteria Four ways to classify bacteria:
Structure
Molecular composition
Physiology
Reaction to specific dyes
Why are bacteria divided in to two separate kingdoms?The RNA in the ribosomes of archaebacteria is different from that of RNA in the ribosomes of eubacteria : Why are bacteria divided in to two separate kingdoms?The RNA in the ribosomes of archaebacteria is different from that of RNA in the ribosomes of eubacteria
What other differences exist between the two kingdoms? : What other differences exist between the two kingdoms?
Kingdom Archaebacteria : Kingdom Archaebacteria More ancient than eubacteria
Live in extreme environments (very hot, cold, salty, acidic)
Less commonly found around us
Don’t cause disease to humans
Have unique lipids in their cell membrane
Have introns in their DNA
Don’t have peptidoglycan in their cell walls
(compound of protein and sugar)
have genes that resemble eubacterial and eukaryotic genes (common asncestor)
What are Introns? : What are Introns? These are parts of DNA that do not carry a code for making proteins (protein synthesis)
Kingdom Eubacteria : Kingdom Eubacteria Less ancient
More common around us (we refer to them as “germs”)
Found everywhere around us
No introns in DNA
Have peptidoglycan in cell wall
Cause disease to humans
Archaebacteria : Archaebacteria Three major groups:
Methanogens
Extreme halophiles
Thermoacidophiles
Methanogens : Methanogens Anaerobic (cannot live in the presence of oxygen)
Live in bottom of swamps, sewage and intestinal tracts of humans and animals
Obtain energy by converting H2 and CO2 into methane gas
Extreme Halophiles : Extreme Halophiles Salt-loving bacteria
Live in the Dead Sea, Great Salt Lake, and other very salty areas where no organism can survive
Obtain energy (ATP) from salt
Thermoacidophiles : Thermoacidophiles Thermo (heat) acido (acid) phile (loving)
Live in temperatures up to 110°c (230°F) and pH less than 2
Live in hot springs, volcanic vents and hydrothermal vents (cracks in ocean floor miles below the surface)
Eubacteria: Photosynthetic Autotrophs : Eubacteria: Photosynthetic Autotrophs Photosynthetic: make their own food from light
Cyanobacteria: blue-green, yellow, or red
ponds, streams, moist areas
Eubacteria: Chemosynthetic Autotrophs : Eubacteria: Chemosynthetic Autotrophs Get energy by breaking down inorganic substances like sulfur and nitrogen
Make nitrogen in the air usable for plants {Very Important}
Structure of Bacteria : Structure of Bacteria Two parts to Bacteria Structure:
Arrangement
Shape
Arrangement : Arrangement Paired: diplo
Grape-like clusters: staphylo
Chains: strepto
Shape : Shape Rod: bacillus
Spheres: coccus
Spirals: spirillum
Examples : Examples Streptococcus: chains of spheres
Staphylospirillum: Grapelike clusters of spirals
Streptobacillus: Chains of rods