Transcript Chap. 19/24 : Bacteria - Fort Thomas Independent Schools

Chap. 23 : Bacteria
I.
Characteristics of Bacteria
1. Unicellular – live in colonies
2. Prokaryotes
3. A sample is called a culture
4. Grown in lab on media
called agar (algae)
5. Domain Archae or Bacteria
A. Archeabacteria
Peptidoglycan - sugar/protein found in
cell walls but only in Eubacteria.
 3 Groups :
--- Methanogens – convert H and CO2 into
methane gas. Forms marsh gas.Found in
cows intestines
--- Halophiles – salt-loving
--- Thermoacidophiles – acid and hot places.
Volcanos and ocean vents.
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B. Eubacteria :Classified by their shape

1. Coccus ( cocci ) – round shape
a. diplococus – pairs of cocci
b. staphylococcus – (boils) – clusters of
cocci.
c. streptococcus – (strept throat) –
chains of cocci
2. Bacillus (bacilli)- rod-shaped
ex. E. coli – found in our intestines and used for
digestion.
ex. Botulism – type of deadly food poisoning
(can goods and oysters)
3. Spirillium (spirilla) – spiral-shaped ~~
ex. Syphyllis – STD
-- Gram staining – process used to identify
eubacteria
a. gram negative – red/pink. Little
peptidoglycan.
b. gram positive – purple. More peptidoglycan
II. Bacterial Structure
III. Respiration
 1. Obligate aerobes – requires oxygen to
live. Ex. Diptheria ( trachae) and TB
(lungs)
 2. Obligate anaerobes – cannot live in
presence of oxygen.
Ex. Tetanus, Syphillis, Halotosis, and
Botulism
3. Facultative Bacteria –can live with or
without oxygen. Ex. E.coli
IV. Adaptations for survival
Endospores – hard outer covering around
some bacteria used to survive harsh
conditions. Some can survive up to a
thousand years. Ex. Botulism and tetanus
V.Reproduction
1. Binary fission – one cell pinching into
two. Asexual ( occurs about every 20
min.) Reason you should take antibiotic
until completely gone.

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2. Conjugation – sexual – two bacteria
exchange their genetic information
through their pili
VI.Benefits of Bacteria
1. Make products like Swiss cheese, pickle,
yogurt, butter, sauerkraut, coffee, cocoa
 2. Breakdown our food
 3. Breakdown waste and return nutrients
back to soil
 4. Fix nitrogen (change N to a form we
can use)
 5. Used as medicines (antibiotics)

VII.Controlling Bacteria
Need warm, wet, dark environment to grow
 1. Canning – heat food, seal containers
while hot, no air
 2. Pasteurization – heating milk to kill
bacteria
 3. Refrigeration and freezing – slows
bacterial growth
 4 Dehydration – getting rid of water in
foods – kills bacteria – ex. pasta
5. Antiseptics – chemicals that kill bacteria
on living things. Ex. Iodine, alcohol
6. Disinfectant – chemicals that kill bacteria
on non-living things. Stronger than
antiseptic. Ex. bleach, ammonia, chlorine
7. Antibiotics (kill bacteria once in body) and
Vaccines ( prevent bacteria from
occurring)
VIII. Blue-green Bacteria: Cyanobacteria
Once considered a plant because they
can photosynthesize. Has cell structure
like bacteria
 Help produce oxygen and fix nitrogen
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