BacteriaBacteria are one-celled prokaryotes, some of which

can cause a disease.

• Most bacteria reproduce by simply dividing into two.

• Antibiotics are drugs that kill bacteria or slow their growth and are used to treat bacterial infections.

• Infections they cause include pneumonia, cystitis and food poisoning bugs like salmonella.

But, did you know not all bacteria are bad? In fact, some friendly types actually help protect us from disease.

Bacteria Bacteria is classified according

to their structure.1. Coccus: spherical bacteria2. Bacillus: rod- shaped3. Spirillum: spiral or

corkscrew- shaped

All bacteria is enclosed by a cell wall which provides extra protection and structure.

Is it Alive?

Characteristics of Organisms:1. Composed of cells2. Perform life functions (growth, digestion, etc.)3. Reproduce4. Interact with environment5. Respond to stimuli

Microbes are a wide variety of organisms. Some microbes do not meet these requirements for living things.

VirusesA virus is a pathogen that

consists of a microscopic core of genetic material surrounded by a protein coating.

• Requires a living cell for reproduction

• Is not made of cells and does not carry out any of the functions of life.

• Viruses ARE NOT considered to be living organism.

A virus reproduces by invading a host cell and taking over the cell causing it to make

copies of the viral DNA/RNA.

Viruses

• Some diseases caused by viruses include smallpox, yellow fever, chickenpox, measles, AIDS, influenza and the common cold.

• Vaccines are used in the prevention of a virus. A vaccine is a weakened or dead form of a pathogen that causes an organism to develop immunity against that pathogen.

Fungi

• A fungus is a single or multi-cellular organism.

• Contains a nucleus and organelles.

• Reproduces through releasing spores.

• Ex. Yeast, mold, mildew, and mushrooms.

• Diseases caused by fungi include: ringworm and athlete’s foot.

Parasite

• A parasite is an organism that lives on or in another organism and benefits at the other’s expense.

• Ex. Protists, tapeworms, mosquitoes, ticks, etc.

• Diseases caused by parasites include: African Sleeping Sickness, Tapeworm, Malaria, etc.

Some diseases are spread by vectors

A vector is an organism that transmits a disease.

Malaria is a disease caused by a parasite in the blood. A mosquito bites a person who has malaria, then bites another person, and the disease is passed to that person.