• Prokaryote: no nucleus or organelles– Chromosome &
plasmids float freely in cytoplasm
• Ribosomes: create proteins
• Flagella: used in movement
• Pili: act as anchors• Capsule: outer coating• Endospore: “cocoon”
that forms around DNA to protect in harsh times
• Many bacteria grow in colonies
• 3 Basic Shapes:
• 1) Bacilli/Bacillus = Rod• 2) Cocci/Coccus = Spherical• 3) Spirilla/Spirillum = Spiral
Bacteria Reproduction
• Binary Fission: asexual reproduction where one cell splits into two cells– Both cells have
identical sets of DNA– Less genetic diversity
• Conjugation: process where DNA is exchanged– Cells connect by pili– DNA exchanged
• Creates genetic diversity
Nutrition• Heterotrophs: feed
on matter produced by others– Saprophytes:
absorb nutrients from dead matter
– Parasites: absorb nutrients from living matter
• Essential to healthy ecosystems
• Obligate Aerobe = must live in oxygen• Obligate Anaerobe = cannot live in oxygen• Facultative Aerobe = can live with or without
oxygen
The bacteria that causes TB lives in your lungs… which type is it?
O2O2 O2 O2
• Cyanobacteria: autotrophic bacteria• Evolutionary Importance
– Early life lived in oceans (no ozone layer)
– Cyanobacteria released O2 into the atmosphere
– O2 recombined into ozone (O3) in the stratosphere
– Protective layer allowed life to evolve on land
UV
UV
Cyanobacteria in Ocean water
Ozone layer (O3) develops over millions of years
Uninhabited land
UV
UVUV
UVBacteriaBacteria
Helpful Bacteria• Helpful in nature
– Cyanobacteria: create O2
– Decomposers: recycle C
– Nitrogen fixer bacteria
• Bacteria have been engineered for human uses:– Food: cheese, bread, yogurt,
sauerkraut
– Medicine: antibiotics
– Industry: insecticides, fuel, environmental cleanup
GRAM NEGATIVE GRAM POSITIVE
Identifying Bacteria Identifying Bacteria • Identified by Gram
Stain test– Gram negative:
• stains pink• harder to treat
– Gram positive:• stains purple• easier to treat
• Treatments differ depending upon results
Kingdom Bacteria
Gram Positive
• Thinner capsule• Stains purple
Gram Negative
• Thicker capsule• Stains pink
Cyanobacteria
• Autotrophs• Created ozone layer
• Live in extreme environments• 1) Methanogens:
– Anaerobic (Obligate Anaerobe)– Produce methane gas as a waste product– Habitat: Swamps, sewage, digestive tract
2) Thermophiles
• Heat and acid loving archaea
• Habitat: Deep sea vents, volcanoes, hot springs (230°F)
3) Halophiles
– Thrive in areas of high salt concentration• Salt normally dehydrates organisms
– Use salt to make energy
Kingdom Archaea
Halophiles
• thrive in salty environments
Methanogens
• live in anaerobic environments• produce methane as waste
Thermophiles
• thrive in extremely hot environments
1) What is the main difference between bacteria and all other life on Earth?
2) What is the purpose of…– ribosomes?– pili?– endospores?– capsule?
3) Name the process where bacteria divide themselves?4) Examine the next slide and identify the cell parts.5) How do the 3 types of respiration differ among bacteria?6) Which archaebacteria love salt?7) How do Gram + and – bacteria differ?8) Which beneficial gas do cyanobacteria release into the
atmosphere?9) What did this gas eventually create?