Domain Bacteria and Domain Archaea

Bacteria: Archaea

BASIC CHARACTERISTIC of Both:• Unicellular• Heterotrophic or Autotrophic• Prokaryotic

Eubacteria “True Bacteria”

• Archaea “Ancient”- extremophiles

- Thermophiles, - Methanogens

(salt)

(anaerobic waste removal) (Hydrothermal vents)

- Halophiles

How do Bacteria and Archaea

differ? Domain Bacteria

Structural:

Peptidoglycan in cell wall

Molecular: Simple RNA

polymerases

• Domain Archaea• Structural:

• No peptidoglycan in cell wall.

• Molecular:• Complex RNA

polymerase

Gram staining is used to identify bacteria.

Gram-negative bacteria have a thin layer of peptidoglycan and stain red/pink.

Gram-positive bacteria have a thicker peptidoglycan layer and stain purple.

– Stains the peptidoglycan layer. – Gram-positive = Stain color - purple, Thick

peptidoglycan cell wall– Gram-negative = Stain color - Pink, Thin

peptidoglycan cell wall + outer membrane.

E. coli B.subtilis

Why are some bacteria resistant to certain

antibiotics?

GRAM NEGATIVE GRAM POSITIVE

How bacterial resistance occurs!

Basic Bacterial Structure

flagellum

pili

cell wall

Nucleic Acid

cellmembrane

Ribosome

Plasmid

Bacteria are Classified by Shape and Growth Pattern

– Spirilla = spiral shaped

– Bacillus = rod shaped

– Coccus = spherical shaped

- Diplo = pair- Strepto = chain- Staphylo = cluster

Test yourself…Classify these bacteria?

Streptobacillus

Diplococcus

Streptococcus

Spirillus

Genetic Variation in Bacteria

Transformation – Bacterial picks up free DNA and adds it in to its own DNA.

Conjugation –One bacteria transfers DNA to another.

Mutation – Random change in a DNA sequence.

How are Bacteria helpful? Benefit to Ecosystems

Decomposition (CO2)

Chemical Cycling Fix nitrogen in the soil (air to soil) Cyanobacteria (photosynthesis)

Bioremediation – The use of organisms to remove or neutralize pollutants from a contaminated site

Provide Nutrients: Digestion of food in gut Cheese, butter, yogurt, sauerkraut

How are bacteria harmful? Pathogens: Cause Disease

Scarlet Fever - Streptococcus pyogenes Strep Throat – Streptococcus pyogenes Bacterial Meningitis - Neisseria meningitidis Lyme Disease - Borrelia burgdorferi

Produce toxins Botulism

Clostridium botulinum The chemical used in botox

Food Spoilage

Antibiotic Resistance

What do we use to fight infection?

Antibiotics

Vaccines

Antiseptic

Antibiotics Vs Vaccines Antibiotics only treat

bacterial infections Given after someone

is infected Prevents bacterial

growth

Vaccines treat viral or bacterial diseases Given prior to

infection Is made up of a

small dose of the pathogen

Creates antibodies to fight future infections

Antibiotic Sensitivity

Antibiotic Sensitivity - the susceptibility of bacteria to antibiotic

To test antibiotic sensitivity - Thin wafers containing an antibiotic are

placed on an agar plate that is growing bacteria. The bacteria are can’t grow next to the antibiotic they are sensitive to.

Zone of inhibition - area around antibiotic disc where bacterial growth is inhibited.

Antibiotic Resistance - No clear zone (indicate antibiotic resistance) Antibiotic discs are identified by the letter on

the top. Antibiotic Identifier

Penicillin P

Chloramphenicol C

Doxycycline D

Streptomycin S

Ciprofloxacin CIP

Control CNTL

Zone of inhibition

P

D

C

CIP

S

CNTL

2cm

4 cm

5 cm

4 cm 1 cm

CIP

S

P

CNTL

D

C

1 cm

2 cm

3 cm

4 cm 0 cm