Bacteria. Hand Washing 1800’s: 25% of women died after childbirth Why? Streptococcus pyogenes...
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Transcript of Bacteria. Hand Washing 1800’s: 25% of women died after childbirth Why? Streptococcus pyogenes...
Bacteria
Hand Washing 1800’s: 25% of women died after childbirth
Why? Streptococcus pyogenes bacteria
But most women were perfectly healthy before entering the hospital.
Doctors were passing the deadly microbes on to healthy women because they NEVER washed their hands!!
*Prokaryotes vs. EukaryotesBefore we examine bacteria we need to know the difference between Prokaryotes and Eukaryotes
There are two types of cells that exist: Prokaryotes and Eukaryotes
Property Eukaryotes Prokaryotes
True nucleus Yes No
Genetic Material Many chromosomes usually
Single chromosome
Cell Division Mitosis + Meiosis Binary or Other
Number of cells in organism
1 or more (to trillions)
1 (unicellular)
Size Larger cells Smaller cell
Metabolism Aerobic (require O2) Anaerobic (no O2 needed)
BacteriaAll bacteria are:
Unicellular
Have prokaryotic cells
Live in a moist environment.
Reproduce mainly through binary fission.
Have one circular chromosome called a plasmid.
There are 2 types of bacteria:ArchaebacteriaEubacteria
Defining Features of Bacteria
1) Shape/Arrangement
2) Cell Wall
3) Nutrition & Gas Exchange
4) Movement
5) Genetic Components/Reproduction
1. Shapes & Arrangements
Eubacteria have many different shapes and arrangements.
Shape Latin Arrangement Latin
Round Coccus (Cocci) Paired Diplo-
Rod Bacillus (Bacilli) Chain Strepto-
Spiral Spirilla Clump Staphylo-
Corkscrew Spirochete
1. Shapes & Arrangements
E. ColiEscherichia coli
(E. coli)
Where is E. coli?- In the human intestines- They help in digestion and vitamin B
and B production
What shape?-Bacillus
How big is E. coli?
2. Cell Wall
Some bacteria are classified by the cell wall’s response to gram stain
Gram stains show differences in amino acid and sugar molecules
Identifying Bacteria
3. Nutrition & Gas ExchangeBacteria can exist as:
1) Aerobic (need oxygen) or anaerobic (do not need oxygen to survive
2) Autotrophic (make own food) or heterotrophic (need to eat food)
3. Nutrition : Types of Autotrophic Bacteria
Photosynthetic Organisms make their own food using energy from light
Chemosynthetic Obtain energy from inorganic compounds such as hydrogen gas to hydrogen sulfide
Do not require light
4. Movement
Cilia: Hair-like projections that work together in rhythm
Flagella (sing: flagellum): Tail-like projection that helps push bacterium (similar to a tad pole)
5. Reproduction in Bacteria
1) AsexualBinary Fission
2) SexualConjugation
Asexual: Binary Fission Similar to mitosis but simpler
DNA replicates and half moves to one end and other half goes to the other
Cross wall divides two identical bacteria
Bacteria can separate or remain together
Makes Diplo-, Staphylo-, Strepto- bacteria
Sexual: Conjugation
Donor and recipient bacteria make cell to cell contact
Via a sex pilus
Plasmids (DNA) are exchanged from donor to recipient
Plasmids are small loops of DNA that separated from the bacterium chromosome
EndosporesSome bacteria form endospores
This allows them to survive under high temperatures, freezing, radiation, drying out etc.
When conditions are suitable, the endospore germinates back into an active bacterium (ranges from weeks to 1000’s of years)
Bacteria and Humans
Strep throat caused by Streptococcus pyogenes
Tooth decay (cavaties) cause by Streptococcus mutans
Bacteria and Humans
Leprosy caused by Mycobacterium leprae
Tetanus (muscle spasm) caused by Clostridium tatani
Archaea• Oldest organisms on
earth = very primitive.• Live in extreme
conditions.• 3 Types:
1. Thermophiles (survive in high temp)
2. Methanogens (survive in high levels of gas)
3. Halophiles (survive in high salt concentrations)
*Comparing Bacteria and Archaea
Homework
Read pages 59-66#1-6, 8, 10 (p.66)