Bacteria

Title :

Bacteria

Author :

Kim Foglia & Kelly Reidell

Number of slides:

14

Slideshow :

Content transcript :

Classification

* Old 5 Kingdom system

* Monera, Protists, Plants, Fungi, Animals

* New 3 Domain system

* reflects a greater understanding of evolution & molecular evidence

* Prokaryote: Bacteria

* Prokaryote: Archaebacteria

* Eukaryotes

* Protists

* Plants

* Fungi

* Animals

Prokaryotes

Domain Bacteria

Domain Archaebacteria

Bacteria live EVERYWHERE!

* Bacteria live in all ecosystems

* on plants & animals

* in plants & animals

* in the soil

* in depths of the oceans

* in extreme cold

* in extreme hot

* in extreme salt

* on the living

* on the dead

Bacterial diversity

Prokaryote Structure

* Unicellular

* bacilli, cocci, spirilli

* Size

* 1/10 size of eukaryote cell

* 1 micron (1um)

* Internal structure

* no internal compartments

* no membrane-bound organelles

* only ribosomes

* circular chromosome, naked DNA

* not wrapped around proteins

Prokaryote vs. Eukaryote Chromosome

Variations in Cell Interior

Prokaryote Cell Wall Structure

Prokaryotic metabolism

* How do bacteria acquire their energy & nutrients?

* photoautotrophs

* photosynthetic bacteria

* chemoautotrophs

* oxidize inorganic compounds

* nitrogen, sulfur, hydrogen…  

* heterotrophs

* live on plant & animal matter

* decomposers & pathogens

Genetic variation in bacteria

* Mutations

* bacteria can reproduce every 20 minutes

* binary fission

* error rate in copying DNA

* 1 in every 200 bacteria has a mutation

* you have billions of E. coli in your gut!

* lots of mutation potential!

* Genetic recombination

* bacteria swap genes

* plasmids

* small supplemental 

circles of DNA

* conjugation

* direct transfer of DNA

Bacteria as pathogens

* Disease-causing microbes

* plant diseases

* wilts, fruit rot, blights

* animal diseases

* tooth decay, ulcers

* anthrax, botulism

* plague, leprosy, “flesh-eating” disease

* STDs: gonorrhea, chlamydia 

* typhoid, cholera 

* TB, pneumonia

* lyme disease

Bacteria as beneficial (& necessary)

* Life on Earth is dependent on bacteria

* decomposers

* recycling of nutrients from dead to living

* nitrogen fixation

* only organisms that can fix N from atmosphere

* needed for synthesis of proteins & nucleic acids

* plant root nodules

* help in digestion (E. coli)

* digest cellulose for herbivores

* cellulase enzyme

* produce vitamins K & B12 for humans

* produce foods & medicines

* from yogurt to insulin