BACTERIANotes

October 19, 2009

Anton van Leeuwenhoek

First to see what would become known as bacteria

Cell Structure Bacteria

› Are prokaryotes› No nucleus

Parts› Genetic material› Cell wall› Cell membrane› Ribosomes› Cytoplams› Flagella

Parts Genetic Material

› Located: inside the cell, but NOT in a nucleus

› Purpose: contains the DNA Cell Wall

› Located: around the outside› Purpose: protects the cell

Parts Continued … Cell Membrane

› Located: inside the Cell Wall› Purpose: controls what material enters and leaves the cell

Ribosomes› Located: in the cytoplasm› Purpose: chemical factories where proteins are made

Cytoplasm› Located: inside the cell membrane

› Purpose: gel-like material that fills the cell

Flagellum› Located: on the outside of the cell

› Purpose: helps the cell move

Parts Continued …

Cell Shapes

Spherical

Rod-like

Spiral

Sizes of Bacteria

Vary Greatly Largest: size of a period at

the end of a sentence Average: much smaller

› .5 to 1 nm

Obtaining Food

Autotrophs› Capture and use the sun’s light› Uses energy from chemicals in its surroundings

Heterotrophs› Consumes other organisms or food that other organisms make

Respiration

Definition: Process of breaking down food to release the food’s energy

Most bacteria need oxygen Those that don’t need

oxygen die if oxygen is present

Reproduction Needs for reproduction

› Plenty of food› Right temperature› Suitable conditions

Types of Reproduction

Asexual› Definition: process involving only one parent to produce offspring that are identical to the parent

› Type: binary fission

Types of Reproduction

Sexual› Definition: process involving two parents who combine their genetic material to produce a new organism which differs from both parents

› Type: conjugation

Endospore Formation

Endospore› Form when conditions become unfavorable for growth

› Definition: small, round, thick-walled, resting cell that forms inside the bacterial cell Contains cell genetic material and some cytoplasm

Role of Bacteria in Nature

Increases oxygen Increases food production Helps with recycling and

environmental cleanup Helps in health maintenance

and medical production

Infectious Diseases Definition: illnesses that pass

from one organism to another How they spread?

› Contact with: infected person infected animalcontaminated objectenvironmental sources

Infected Person

Direct contact› Hugging› Kissing› Touching

Indirect contact› Inhaling germs in the air from sneezes or coughs

Infected Animal

Animal bites› Rabies

Tick bites› Lyme Disease

Mosquito bites› West Nile› Encephalitis

Contaminated Objects Touching or using others

eating utensils Drinking from someone else’s

glasses, water bottles, soda’s Touching objects that were

sneezed or coughed on, then touching your eyes, mouth, or nose

Environmental Sources

Eating foods that are contaminated› salmonella

Bacteria that enters a wound› Clostridium tetani

Toxins- poison that causes deadly diseases› tetanus

Treating Infectious Disease

Bacterial Infections› Antibiotics

Definition: chemical that kills bacteria without harming a person’s cells

Example: penicillin

› Antibiotic Resistance Definition: when bacteria are able to survive in the presence of an antibiotic

Treating Infectious Disease

Viral Infections› No current cures› To help:

Over-the-counter medications Bed rest Drink lots of fluids Eat well-balances meals

Preventing Infectious Disease Vaccines

› Definition: substance introduced into the body to stimulate the production of chemicals that destroy specific viruses or bacteriaMade by dead or altered viruses or bacteria

Protecting Yourself How?

› Keep your body healthy› Eat nutritious foods› Get enough sleep› Get enough fluids› Get enough exercise› Wash your hands often› Don’t share drinks, food, or utensils

Protecting Yourself› Store food properly› Keep kitchen surfaces clean› Cook meat completely› When you get ill

Get plenty of restDon’t come to school sick

You might infect others—including me

Follow your doctors orders