Chapter 19Bacteria and

Viruses

Did you know… The african lung fish has a breathing

adaptation that helps it survive in shallow waters that are subject to drought.

It burrows into the mud, covers itself with mucus and becomes dormant.

For several months until the rain falls it breaths through its mouth and lungs!

GRAB YOUR CLICKERS

Coming for a short time only…Thoughts to ponder… Why is it if you send something by boat it

is called cargo but if you send it by truck it is called a shipment?

Structure of a Eubacterium

NO NUCLEUS – still have genetic material, chromosomes, etc. and ribosomes

A B

CED F

G

Identifying Prokaryotes-Shapes

Bacilli Cocci Spirilla

STAPH – occurs in clusters

STREP – occurs in chains

Bacteria are identified based on… Type of cell wall shape Method of obtaining energy Gram staining characteristics

Evolutionary adaptations Reproduce rapidly Utilize substances that are harmful to

other organisms High rate of mutation Can exist under adverse conditions

Bacterial reproduction Conjugation – exchange genetic

information Binary fission replication

Gram + and Gram - Bacteria Eubacteria only Differ in response to antibiotics Gram + turn violet when treated with

gram stain

Controlling Bacteria Sterilization by heat – used in restaurants and

hospitals. Disinfectants – chemical solutions that kill

bacteria – overuse of purel, etc. will create problems making them more dangerous and harder to kill. (Tell your mom to lay off the 409 on the countertop, soap and water work just as well!0)

Food processing – either keeping food cold in a refrigerator, or heating it to high temperatures to kill bacteria

Diseases caused by bacteria

PATHOGEN Disease causing agent

Cause disease in 2 ways1. Damage the cells and tissue of the

infected organism by breaking down the cells for food.

2. Release toxins or poisons that travel through the body and disrupt normal activity.

Prevention Vaccines – weakened or dead pathogens,

prompts immune system to produce immunity to the disease.

Antibiotics – block growth and reproduction of bacteria

Some Diseases Caused by Bacteria

Lyme Disease Scarlett FeverTetanus ImpetigoTuberculosis SyphilisDiphtheria GonorrheaBacterial Meningitis Rocky Mountain Spotted FeverStrep Throat Salmonella

Tooth decayAnthraxBotulismCat’s Scratch DiseasePneumonia

Warm Up List the 2 ways bacteria can cause

disease. What three methods will prevent bacteria

growth in food.

Bacterium with flagella

Bacterial conjugation is the transfer of genetic material between bacteria through direct cell-to-cell contact

Some bacteria can form spores when living conditions become poor. They can remain dormant thousands of years if they have to…until conditions improve! The spores protect their DNA in a hard shell.

Bacteria are small but so very important. We have already studied how they decompose dead things and how they perform nitrogen fixation so plants can be fertilized.

But did you know what bacteria do for US as HUMANS?

Yogurt

Vinegar

Cheese

These are all made for us by bacteria.

And the yogurt has bacteria that help your digestion!!!

Other things bacteria do for us…. http://www.microbeworld.org/know/everyd

ay.aspx

Antibiotic Resistance in Bacteria Natural Selection is everywhere. One dramatic

example of evolution in action poses a serious threat to public health. Many kinds of disease-causing bacteria are evolving resistance to antibiotics. The high rate of DNA mutation found in bacteria causes them to mutate relatively quickly, and evolve antibiotic resistance. Scientists are racing to produce new antibiotics to combat this problem.

Bacteria on a piece of food (SEM)

Bacilli bacteria (one has just divided)