An introduction to bacteriaAn introduction to bacteria

They Are EverywhereThey Are Everywhere

ProkaryotesProkaryotes ProkaryoteProkaryote: : Single-celledSingle-celled organism organism

that lacks a that lacks a true nucleustrue nucleus (also called (also called bacteriabacteria))

DNA is not surrounded by a DNA is not surrounded by a nuclear nuclear membranemembrane, have no membrane , have no membrane bound bound organelles.organelles.

Cover almost every Cover almost every

cmcm22 of earth! of earth!

Size MattersSize Matters Prokaryotes = 1-5 micrometersProkaryotes = 1-5 micrometers Eukaryotes = 10-100 micrometersEukaryotes = 10-100 micrometers

Vs.

Prokaryotic cells are much smaller than eukaryotic cells.

One to TwoOne to Two *Until recently all prokaryotes were *Until recently all prokaryotes were

one kingdom, Moneraone kingdom, Monera Monera is now split into 2 Monera is now split into 2 kingdomskingdoms:: Eubacteria, ArchaebacteriaEubacteria, Archaebacteria

Now three domains

1)Eubacteria/Bacteria

2)Archaea

3)Eukaryota/Eukarya

ArchaebacteriaArchaebacteria!!

A hot springs in Yellowstone National park!

ArchaeabacteriaArchaeabacteria

Lack Lack peptidoglycanpeptidoglycan walls and have walls and have different membrane lipids than different membrane lipids than EubacteriaEubacteria

DNA sequences are DNA sequences are closercloser to to Eukaryotes than BacteriaEukaryotes than Bacteria

ExtremoExtremophilesphiles – – ‘‘phileo’ in Greek means phileo’ in Greek means

lovelove Extremophiles:Extremophiles:– Live in extreme environments!Live in extreme environments!

HalophilicHalophilic: salt loving: salt loving

Thermophilic: Thermophilic: heat lovingheat loving

Methanogens – produce methane gas

Live in the gut of mammals,

sewage disposalplants and swamps

EubacteriaEubacteria Largest of prokaryote groupsLargest of prokaryote groups *Have cell walls that contain *Have cell walls that contain

peptidoglycanpeptidoglycan (carbohydrate) (carbohydrate) Find everywhere on earth.Find everywhere on earth.

ShapesShapes Three ShapesThree Shapes

1) Bacilli

(rod-shaped)

2) Cocci

(spherical)

3) Spirilla

(spiral or corkscrew)

“Strep” throat

ShapesShapes

SS S

SSSSSS S

Streptococci Streptobacilli Streptospirilla

Staphylococci Staphylobacilli Staphylospirilla

Form chains or strings

Form clumps like grapes

Rod shaped = Bacilli

Round = Cocci

Spiral shaped = spirilla

Cell WallsCell Walls Two Types of Eubacteria:Two Types of Eubacteria:

– Gram-PositiveGram-Positive ThickThick peptidoglycan walls peptidoglycan walls Turn Turn dark purpledark purple when stained when stained

– Gram-NegativeGram-Negative Much thinner walls inside an outer lipid layerMuch thinner walls inside an outer lipid layer Appear Appear pink or light redpink or light red

FlagellaRibosome

Pili

Cell membrane

DNA

Cytoplasm

Plasmid

Cell wall

Capsule

Pili - Help withconjugation – transferring of genetic material p.558,Stickto host’s cells

Flagella:Movement

Ribosomes- Makingproteins

DNA - Carries the genetic material

Cytoplasm - Contains DNA, Proteins and plasmid

Plasmid – piece of DNA , plays role during conjugation

Capsule – Protects against drying out, chemicals and host’s white blood cells.

Cell wall - Protects, givescell shapeEubacteria–has peptidoglycan

Cell membrane – Regulates the movement of materials in and out of the cell

Conjugation

Pili – forming conjugation bridge

EnergyEnergy

HeterotrophsHeterotrophs Parasitic – Cause diseases Parasitic – Cause diseases

(pathogens)(pathogens)

Saprophytic Saprophytic – Feed on dead tissues – Feed on dead tissues - Decomposers- Decomposers

AutotrophsAutotrophs

Photoautotrophs:Photoautotrophs: – Use light energy to convert COUse light energy to convert CO22 and H and H22O O

to food (like plants)to food (like plants)– Ex: Ex: cyanobacteriacyanobacteria

Chemoautotrophs:Chemoautotrophs:– Use Use chemicalchemical energy to convert CO energy to convert CO22

and Hand H22O to food O to food

Releasing EnergyReleasing Energy Obligate AerobesObligate Aerobes::

– Require constant supply of oxygenRequire constant supply of oxygen Obligate AnaerobesObligate Anaerobes::

– Do notDo not require oxygen . . . It kills them require oxygen . . . It kills them Facultative AnaerobesFacultative Anaerobes::

– Do not require oxygen, but can live with Do not require oxygen, but can live with itit

– Ex: E. coli Ex: E. coli

*Growth and Reproduction*Growth and Reproduction

Some bacteria can divide every 20 Some bacteria can divide every 20 minutesminutes– If there was unlimited resources 1 If there was unlimited resources 1

bacteria could grow into a mass 4000 bacteria could grow into a mass 4000 times the mass of earth in just 48 times the mass of earth in just 48 hours!!!hours!!!

ReproductionReproduction

Binary fission

1) Binary Fission1) Binary Fission Binary Fission: Binary Fission:

– Asexual reproduction where organism Asexual reproduction where organism replicates replicates DNA DNA and divides in halfand divides in half

– Produces two Produces two identical identical daughter cellsdaughter cells

2) 2) ConjugationConjugationConjugation: (“Sexual” reproduction)

A type of sexual reproduction where organism exchange genetic information

3. Forming Endospores

• Help survive unfavorable conditions.

Anthrax spores

Some are BAD and make us ill

StreptococcusStreptococcus

Strep throat

Pneumonia

Tetanus (lock jaw)Tetanus (lock jaw)

E. coliE. coli

Affects nervous system

Some in our intestines … others are

pathogens that can cause kidney

failure

BacteriaBacteriaCan be bad … but can be good

Make vitamins that Make vitamins that we cannot makewe cannot make

ourselvesourselves

DecomposersDecomposers *Help breakdown sewage treatment *Help breakdown sewage treatment

waterwater

Feel better with??

Nitrogen FixationNitrogen Fixation Converting nitrogen gas into a form Converting nitrogen gas into a form

plants can use (plants can use (nitrates – NOnitrates – NO33))– Allows nitrogen to cycle through Allows nitrogen to cycle through

biospherebiosphere

For example Rhizobium living in the roots of legumes such as soybean plants.

Other UsesOther Uses Oil digestion/Oil digestion/Clean up of pollutantsClean up of pollutants

(Bioremediation)(Bioremediation)

Are living:1. Made up of cells2. Have DNA3. Grow and develop4. Use energy5. Homeostasis6. Reproduction7. Respond to stimuli8. Evolve/Show adaptations – resistant

bacteria9. Show some type of organization – Flagella,

pili, ribosomes, cell wall