Bacteria

The Bacteria Cell• Not discovered until 1600 by our

buddy Anton van Leeuwenhoek• Bacteria are prokaryotes (have no

nucleus)• Their genetic material in their cells is

not contained in a nucleus• Bacteria are living organisms

because they use energy, grow, and respond to their surroundings.

Bacteria Structure

• Bacterial cells are surrounded by a rigid cell wall. Inside the cell wall is the membrane

• The inside is filled with cytoplasm, ribosomes and genetic protein

• May have flagellum that helps a cell to move

•ALL are prokaryotes•All are unicellular•Some are Autotrophs & Some are Heterotrophs

Bacteria Cell Shape and Size

• One of three basic shapes1. Spherical2. Rodlike3. Spiral

• It is the chemical make up of the cell that determines its shape

• The shape helps scientist determine type

Cell Shape

Cell Size• Size vary greatly; average is .5 to 1 micrometer

• A micrometeri(um) is one millionth of a meter

I’m Hungry(Obtaining Food and Energy)

• Bacteria must have a source of food and a way of breaking down the food to release energy

• Some bacteria are autotrophs making their own food through the process of photosynthesis or using chemical substances in their environment

I’m Still Hungry

• Other bacteria are heterotrophs• They must consume other organisms

or the food that other organisms make

• May consume a variety of foods – from milk to meat, which you might also eat, to the decaying leaves on forest floor

Respiration• The process of breaking down food to

release its energy is called respiration

Organic compounds + Oxygen → Carbon dioxide + Water +

Energy

Reproduction• When bacteria have plenty of food, the

right temperature, and other suitable conditions, they thrive and reproduce frequently

• Two Type– Asexual Reproduction

• Binary fission is a form of asexual reproduce– Sexual Reproduction

• Conjugation; transfers some of its genetic material into another bacterium through thread-like bridge

  Asexual Reproduction Sexual ReproductionName of Process Binary Fission Conjugation

Number of Parents 1 2What   Occurs  in the Process

The cell duplicates its genetic material, then divides into 2 separate 

cells

One bacterium transfers some genetic material to another through threadlike 

bridgeResult  of Process

New cells identical to parent

Bacteria are genetically different 

from parent

Endospore Formation• When conditions in the environment

become unfavorable for growth some bacteria form endospores

• Endospores are small rounded, thick-walled resting cell that form inside a bacteria cell containing the cell’s genetic material and some cytoplasm

• Can resist freezing, heating and drying they can survive for many years

The Role of Bacteria in Nature

• Bacteria are involved in:

–O2 production

–food production, –environmental recycling and cleanup, –Medicine production

Oxygen Production

• Scientist credit autotrophic bacteria for making our earth habitable for life.

• The autotrophic bacteia use the sun’s energy to produce food and a waste product is oxygen

Food Production• Can help create food such as

sourdough bread, yogurt, sour cream, and cheeses

• Can also cause food to spoil• Refrigerating and heating help slow

down spoilage• Pasteurization (Louis Pasteur) is

heating food to a temperature that is high enough to kill most harmful bacteria with changing the taste.

Environmental Recycling

• Bacteria are the “decomposers” –organism that break down large chemicals in dead organisms into small chemicals

• Return basic chemicals back to the environment to be used again

• Nitrogen-fixing bacteria help plants by converting nitrogen gas from the air into nitrogen products the plants can use.

Cleanup Crew• Cup of oil anyone?  Some bacteria can break down oil converting poisonous chemicals into harmless substances

What role do bacterial decomposers play in the

environment?

Bacterial decomposer play a very important role in the environment by breaking down dead organism into basic chemicals that other organism can reuse.

Health and Medicine

• In your digestive system• Make vitamins• Prevent harmful bacteria

from attaching to your intestines

• genetically altered bacteria help make scientist produce insulin to help people with diabetes