Bacteria BACTERIA

Bacteria (Monerans)– Kingdoms Archaebacteria and Eubacteria There are more bacteria on Earth than stars in the sky! The closest estimate is that there are 5 million trillion trillion bacteria on Earth – that’s a 5 with 30 zeroes after it. Bacteria produce the air we breathe, clean the water we drink, and create fertile soil. Less than one percent of bacteria cause diseases.

Bacteria structure – prokaryotic cell plasmid

Bacteria Growth Curve

Most bacteria die when conditions get bad: These conditions could be a change in temperature, loss of food, change in pH, etc. Some bacteria can preserve themselves during bad times, then they can regrow and resume their lives. They do this by producing an endospore. Endospores can preserve the cell’s DNA until conditions get better again. They are resistant to all the bad conditions.

Steps in formation of an endospore Endospore production – preserves the cell during hard times– not a form of reproduction Steps in formation of an endospore

Endospore Bacteria that are harmful to humans and that form endospores: Clostridium tetani – causes tetanus Clostridium botulinum – causes food deadly poisoning

Binary Fission – bacteria can divide as often as every 20 minutes!

Origin of Monerans Archaebacteria usually found in harsh environments – hot, salty, smelly! Ancient – probably resemble the first bacteria

Methanogens produce methane – live in digestive tract of mammals, in swamps and sewage.

thermophiles can live in extremely hot water – found in hot springs

halophiles Live in very salty water, such as the Great Salt Lake in Utah and the Dead Sea

Eubacteria – true bacteria Many types – modern bacteria Classification is by: Cell shape Cell wall composition Nutrition Respiration

Cell Shape Coccus - round Bacillus - rod spirillum

Names can tell a lot about the bacterial growth Some bacteria grow alone Diplo…means two Diplococcus Diplobacillus or Strepto… means chain - as in streptococcus - and streptobacillus Staphylo… means cluster As in staphlyococcus

Cell Wall Composition – gram positive or gram negative Gram Positive Gram negative Stains blue stains pink

Nutrition – Autotrophic or Heterotrophic Autotrophs – make their own food Use sun’s energy or chemical energy

Most Monerans are Heterotrophs Escherichia coli spirillum anthrax

Respiration – process of getting energy from food Aerobic Need oxygen Can’t live without oxygen = obligate aerobes EX – TUBERCULOSIS BACTERIUM Prefers to live with oxygen = facultative aerobes Tb lung

Anaerobic – don’t need oxYgen SOME CAN’T SURVIVE WITH OXYGEN – THESE ARE OBLIGATE ANAEROBES EX – TETANUS This baby probably got tetanus from honey – don’t give honey to a baby!

SOME CAN LIVE WITH OXYGEN BUT PREFER TO LIVE WITHOUT IT – fACULTATIVE ANAEROBES E. coli

How Important are bacteria to the world? Decomposition – most important function for living things. What happens to all the dead bodies? Here is a bacterium of decay

Food web

Nitrogen cycle

Cow Digestion Bacteria in the stomach

Tooth Decay Don’t forget to brush and floss your teeth!

Foods from bacteria cheese yogurt sauerkraut

What conditions do bacteria need for the best growth? Food source (your soup is good) Proper temperature - human pathogens (disease causers) live best at 98.6 F. Moisture Oxygen (aerobes) or not (anaerobes) Change any of these and the growth of bacteria can be slowed down or stopped.

We compete with bacteria for our food – they eat the same stuff we do… We compete with bacteria for our food – they eat the same stuff we do…. How do we preserve our food? Drying (prunes) salting refrigeration pickling freezing

Diseases caused by bacteria Anthrax – a natural pathogen that can be used for bioterrorism

Lyme disease – causes illness and can lead to arthritis

plague gonorrhea Strep throat

Food poisoning Salmonella food poisoning – from eggs, chicken, mayonnaise Botulism – from improperly canned foods

Antibiotics, if used cautiously, can cure bacterial infections

Antibiotics are tested using Petri dishes and paper soaked in the antibiotic – anywhere the antibiotic inhibits growth, a zone of inhibition will be seen Most effective Not effective

Here is a white blood cell attacking a bacillus

Uses of bacteria other than food production Bioremediation – using microorganisms to rid environment of harmful substances Ex – oil spill site Hazardous waste site Sewage treatment

Medical uses of bacteria Genetic engineering to produce medical products – Insulin Human growth hormone Gene for human insulin or hgh Now all cells will have the gene and will make the product

That’s all folks!