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Bacteria
Chapter 23
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
DIFFERENCES BASED UPON RNA MAKEUP
1.
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
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

hot and acidic enviornments

They are found in such places
as acidic sulfur springs,
undersea vents (smokers) and
volcanoes
2. Domain Bacteria


Most abundant domain!
Examples: Cyanobacteria,
chlamydia, Lyme Disease,
botulism, TB, E. coli, anthrax,
nitrogen-fixing bacteria

Classified based on:
 Gram stain
 Shape
 Biochemical properties
Gram Stain
Gram Positive Bacteria
 Simple cell wall with lots
of peptidoglycan
 Stains purple
Gram Negative Bacteria
 Complex cell wall with
little peptidoglycan
 Stains pink
Bacterial Shapes

Spirilla (spiral-shaped)

Bacilli (rod-shaped)

Cocci (sphere-shaped)
Streptococci – long chains
 Staphylococci - clusters

Bacterial Groups
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
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







Probiotics- useful bacteria in your gut
Recycle compounds from dead organisms
Create organic compounds
Food production (buttermilk, sour cream,
yogurt, cottage cheese, sauerkraut, pickles)
Produce fuels
Insecticides
Bioremdiation: break down pollutants
Video