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Bacteria
Chapter 23
Intro To
Bacteria
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2:55-end)
Bacterial Classification
Section 23.1
REVIEW: All Bacteria are
Prokaryotes

Prokaryotes:

Eukaryotes:

“Before nucleus”

“True nucleus”

No nucleus

Have nucleus

No membrane bound
organelles

Have membrane bound
organelles
Two Domains of Bacteria
1.
1.
DIFFERENCES BASED UPON RNA MAKEUP
Domain Bacteria

2.
Kingdom Eubacteria
Domain Archaea
Kingdom Archaebacteria
 More related to eukaryotes


based upon rRNA & gene comparison
1. Domain Archaea

Lack peptidoglycan (protein-carbohydrate
compound) in cell wall

Usually located in extreme conditions like:
swamps, salt lakes, and hot springs

Three main types:
A. Methanogens
 B. Extreme halophlies
 C. Thermoacidophiles

Pyrodictium occultum is a
marine organism commonly
found in deep-sea hydrothermal
vents.
A. Methanogens

Energy source: from converting H2 and CO2
into methane gas.

Live in areas absent of oxygen like swamps,
sewage, and intestinal tract

Gas build up is released as a fart
B. Extreme Halophiles

Salt loving bacteria

Location: anywhere there is a high salt
concentrations like the Great Salt Lake and the
Dead Sea.

Energy source: salt need for them to make ATP
C. Thermoacidophiles

As their name
suggests, these like it
hot and acidic

They are found in
such places as acidic
sulfur springs
,undersea vents
(smokers) and
volcanoes.
2. Domain Bacteria

Most abundant domain!

Examples of eubacteria are:
 salmonella
 Escherichia coli (E. coli)
 treponema (syphilis)
 borrelia (lyme disease)
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Identifying Bacteria:
1.
Shape
A.
B.
C.
Bacilla (rod-shaped)
Spirilla (spiral-shaped)
Cocci (sphere-shaped)
Are they always alone? 
Nope!
cocci are known for
living in groups:
•
Streptococci
(cocci in chains)
•
Staphylococci
(cocci in clusters)
1.
2.
Shape
Gram Stains:
Bacteria turn red or purple depending on the makeup of their cell walls.
+ Gram-positive: (purple)
(Simple cell wall with
lots of peptoglycan)
- Gram-negative: (red)
(Complex cell wall with
little peptoglycan)
3. Classifying bacteria by
what they need…
1. Energy:
Phototrophs – energy from sun
Chemotrophs – energy from other organisms
2. Carbon:
Heterotrophs – gets carbon from other sources
Autotrophs – carbon from CO2 or other gasses
Ridiculously Long Words:
Photoheterotroph
Chemoheterotroph
Photoautotroph
Chemoautotroph
4. Oxygen or not?
THINK OBLIGATION
Obligate
Aerobes
O
2
Facultative
Anaerobes
idc.
Obligate
Anaerobes
O
2
Practice…
Please classify these specimens according to:
1. Shape
2. Gram-Stain
3. Energy/Carbon needs
4. Oxygen Preference
Specimen A:
This bacteria is rodshaped, colored purple
when Gram-stained,
gets both its energy and
Carbon from a host
organism
that it infects, and
cannot live in the
presence of oxygen.
•
Specimen B:

This bacteria is
round, but found in
chains. It turns red
in a Gram-stain, and
gets its energy from
the sun, and carbon
from gas in the
atmosphere. It
cannot live without
oxygen.
Bacterial Groups (that you DO need to know!)
1.
2.
3.
4.
5.
Proteobacteria
Gram-Positive Bacteria
Cyanobacteria
Spriochetes
Chlamydia
1. Proteobacteria


Largest and most diverse group
Many live symbiotically with other organisms


Nitrogen-fixing bacteria
Some cause diseases
Rocky Mountain spotted fever
 Stomach ulcers
 Foodborne illnesses

2. Gram-Positive Bacteria

Some cause diseases
Strep throat
 Botulism (Botox)
 Anthrax
 TB
 Leprosy


A few make antibiotics that kill other bacteria
3. Cyanobacteria

Undergo photosynthesis for energy

Simplest life requirements

First oxygen-producing organisms
on Earth!
4. Spirochetes

Gram-negative

Spiral-shaped bacteria

Examples: syphilis & Lyme disease
5. Chlamydia

Gram-negative
Coccoid shaped, no peptidoglycan

Causes a STD that lives inside animals

Biology of Prokaryotes
Section 23.2
Bacterial Structures

Most bacteria are composed of the following
parts:
Outer cell wall
 Cell membrane


Internal foldings = thylakoids (photosynthesis)
Cytoplasm
 Ribosomes
 DNA
 Small molecules and ions

Endospores



Can form in gram + bacteria
Thick-coated, resistant structures
Form when environmental conditions are poor

Resistant to high temp, strong chemicals, radiation,
drying, etc.
Prokaryotic Movement

Taxis: movement toward or away from stimuli



Chemotaxis: chemical stimuli
Physical movement aided by flagella or slime
Patterns of movement: wave-like contractions or
corkscrew rotation
How do bacteria reproduce?

Asexually via….
 Binary fission
 Budding
 permits the development
of more complex colonial
structures
Budding
Binary
fission
Genetic Recombination

Three ways that bacteria can exchange and
acquire new combinations of DNA
1. Transformation
 2. Conjugation
 3. Transduction

1. Transformation

When a bacteria takes on
DNA from its external
environment.
 Then this new DNA
is substituted into the
bacterial DNA
2. Conjugation

When two bacterium
bind together and one
bacterium transfers
genetic information
to the other.

DNA channeled
through the sex pilus
3. Transduction
Steps:
1. Virus obtains a fragment
of bacteria DNA from its
host
2. Virus multiplies inside
host (replicating the
bacterial DNA as well)
3. Virus breaks out of host
cell and invades new
bacteria
4. New bacterial host will get
old host’s DNA via the
virus
Know these parts of the bacteria!
Cell Wall
 Outer Membrane
 Cell Membrane
 Cytoplasm
 Chromosome
 Plasmid
Capsule & Slime Layer
 Endospore
 Pilus
 Flagellum


Click above for more info!
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Bacteria and Humans
Section 23.3
Bacterial Diseases

Pathology – The study of diseases

Pathogens – anything that causes disease
Bacteria
 Viruses
 Fungi
 Protists

Cholera attacking a cell
Bacterial Poisons

Toxins – bacterial poisons that cause disease
1.
Exotoxins – made up of proteins
Secreted by the gram + bacteria to surroundings
 Example: tetanus

2.
Endotoxins – made up of lipids and carbs.
Released by dead gram – bacteria
 Cause fever, body ache, weakness, and damage

How to treat diseases…

Antibiotics – fungi or
bacteria that combat
infection by interfering
with various cellular
functions

May lead to Antibiotic
Resistance
 Caused by not
taking full dose of
antibiotics
= 1 day to die
= 4 days to die
= 2 days to die
= 6 days to die
Initial
infection
After 1 day
w/ antibiotics
After 3 days
w/ antibiotics
Emerging Infection Diseases

Zoonosis: a disease that passes from wild
animals to humans
Increase due to global travel of humans &
destruction of natural habitat
 Example: Lyme disease


Other examples
Useful Bacteria to Humans







Break down wastes
Recycle compounds from dead organisms
Create organic compounds
Food production (buttermilk, sour cream,
yogurt, cottage cheese, sauerkraut, pickles)
Produce fuels
In insecticides
Bioremdiation: break down pollutants
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