BACTERIA

BACTERIA• Bacteria are microscopic, single celled organisms

that exist all around you and inside you.• Unlike other single celled organisms, bacteria do

not have a nucleus or organelles. They just have hereditary material floating in cytoplasm contained in a cell wall and cell membrane.

• If a bacterium does not have a nucleus or organelles, is it larger or smaller than other single celled organisms?

Hereditary Material

Cytoplasm

Cell Wall

Cell Membrane

Bacterial Shapes• Bacteria have three basic shapes:• Spirilla (sprial) • Bacillus (rode shaped)• Coccus (round)

• Bacteria can occur alone, in pairs, in clumps, or in chains.

Where bacteria live• Bacteria live everywhere! In your body, in our

food, on the surfaces you touch, in hot springs, on ice, etc.

• On the outside of a bacterium is a capsule. This capsule:• Prevents the cell from drying out. • Helps the cell stick to other things (they cannot move on

their own)• Helps it survive in a variety of environments.

• Bacteria need warmth, moisture, and food to survive. They grow best at body temperature.

• If adverse conditions arise, the bacterium forms an endoscope. This covering protects the hereditary material conditions improve.

What bacteria eat• Bacteria need food for energy• Autotrophs: make their own food through photosynthesis.• Heterotrophs: find and consume food.

• Bacteria break down their food through a process called respirations. • Aerobic respiration: with oxygen• Anaerobic respiration: without oxygen

• Some bacteria are decomposers. They consume the remains of dead organisms and break down the organic matter.

• Some people consider decomposers to be harmful, but consider if the remains of every living thing (insects, animals, plants, etc.) that ever lived were still on the Earth today. Bacteria breaks down these remains and turn them back into their original chemicals which are carried into the ground where they nourish new plant growth. That is very helpful.

How bacteria reproduce• Bacteria reproduce through Binary Fission. This

means they split in half and create a perfect copy of themselves. The frequency of fission depends on the temperature.

• ½ hour at 90 degrees.• 1 hour at 70 degrees.• 2 hours at 60 degrees.• 6 hours at 40 degrees.• 20 hours at 32 degrees• 60 hours at 28 degrees.• If bacteria are capable of doubling every 30

minutes, how many bacteria can be formed in a half day from just one starting bacterium?

• This is the growth pattern for one bacterium during the course of one afternoon. How many bacteria are on Earth?

• On average there are:• 40 million bacteria cells in a gram of soil.• 1 million bacteria cells in a milliliter of fresh water.

• it is estimated there are approximately five nonillion bacteria on Earth!

Bacteria are Helpful and Harmful• Bacteria are both helpful and harmful.• Helpful• Sewage treatment• Digest food• Nitrogen for plants• Make some foods

• Harmful• Disease• Infection

• Ways to protect yourself from harmful bacteria:• Wash your body with soap and warm water.• Wash your clothes.• Brush your teeth.• Keep the house clean