Bacteria Bacteria are small living organisms found almost everywhere on the earth. Bacteria are prokaryotes which are typically unicellular. *There.

Bacteria

Bacteria are small living organisms found almost everywhere on the earth.

Bacteria are prokaryotes which are typically unicellular.

*There are more bacteria living in your mouth than there are people living on Earth!

Classification of Bacteria

Bacteria are classified into two major Kingdoms : Archaebacteria and Eubacteria.

Archaebacteria : live without oxygen, and obtain their energy from inorganic compounds.

Archaebacteria

Archaebacteria can survive and thrive in “harsh” environments.

Examples of archaebacteria include : methane-producting bacteria in cows stomachs, salt-loving bacteria, and heat and acid loving bacteria which thrive in hot springs.

Archaebacteria

Archaebacteria found in the stomachs of cows allow for the cow to break down and digest the “cellulose” in plant cells. These bacteria help cows turn cellulose into glucose. The bacteria produce methane gas in this process.

Eubacteria

Eubacteria differ from Archaebacteria in differences of cell walls, plasma membrane, and sequence of DNA bases.

Eubacteria

Most common bacteria are classified as eubacteria.

Eubacteria include the phostosynthetic bacteria called cyanobacteria.

Bacteria Structure

Flagella (some) Capsule (some) Cell wall Plasma membrane DNA Pili (some)

Bacteria have different shapes and structures, but structures found in bacteria include :

Bacteria Shapes

Most bacteria are found in “colonies”.

Bacteria can be round, spiral, or rod shaped.

Round : coccus Spiral : spirillum Rod : bacillus

Bacteria are also classified into the shape of groups or colonies they form.

• Diplo : paired cells

• Staphylo: grapelike clusters

• Strepto: long chains

Bacteria Reproduce by:

Binary Fission (Asexual)

Binary fission involves the copying of the DNA and the splitting into two new cells.

Conjugation (Sexual)In conjugation one bacteria is able to transfer its DNA into another bacteria by means of a pilus (pili)

Bacteria Reproduction

Under optimum conditions bacteria can reproduce every 20 minutes.

Bacteria reproduction is controlled by various factors including : temperature and food availability.

Bacteria- Cell Wall Structure

Bacteria are divided into two groups based upon the composition of their cell walls.

Gram positive : two layers ( lipid, peptidoglycan – sugar/amino acids network)

Gram negative : three layers, lipid, peptidoglycan, and lipopolysaccharide.

Gram +

Gram -

Antibiotics

Most antibiotics aim to break down part of the cell wall to cause water to move in and rupture the bacteria cell.

Penicillin is one bacteria to work this way.

Bacteria

One major role of bacteria in the envrironment is to “fix” nitrogen from the atmosphere into a useable form for plants.

Rhizobium bacteria live on legume roots.

Bacteria - Decomposers

Bacteria break down organic matter in dead organisms.

These heterotrophic bacteria help recycle nutrients from dead plants and animals back into the soil.

Bacteria help break down leaves into useable compounds in the soil.

Bacteria

Bacteria also are used to make antibiotics. Some helpful bacteria will produce chemicals which will kill pathogenic bacteria.

Streptomycin and erythromycin are a few examples of antibiotics made from bacteria.

Bacteria Caused Diseases

Bacteria can cause the following diseases:

Tuberculosis Pneumonia Strep throat Staph infections Scarlet fever Syphilis Gonorrhea Chlamydia Boils Tetanus Lyme disease Ear infections

Bacteria and Disease

Bubonic Plague/Black Death.

In the 1330’s the bubonic plague originated in China. This disease caused by bacteria spread quickly to England and other parts of present day Europe.

This bacteria was mainly found on rodents but fleas are thought to have carried it to humans.

Bubonic Plague

The bubonic plague killed an estimated 1/3rd of all Europeans.

The bacteria caused boils which started as red bumbs on the skin, and then turned into black dots. “Black Death”.

The bacteria Yersinia pestis is thought to have caused this disease.

Exit Slip

1. What is the name of this bacteria?

2. What is the name of this bacteria?

3. Draw a staphylobacillus bacterial colony.