 Discovered in the late 1600s by Anton van Leeuwenhoek, by accident.  Bacteria are prokaryotes (single celled)  Their genetic material is not contained in a nucleus.

 Surrounded by a rigid cell wall.  Just inside the cell wall is the cell membrane.  The region inside the cell membrane is called the cytoplasm.  Within the cytoplasm are tiny structures called ribosomes and the cells genetic material.  May also have a flagellum, which helps with movement.

 Spherical  Rodlike  Spiral  The chemical makeup of the cell determines its shape.  Shapes, help identify types of bacteria

 The average size for a bacterial cell is 0.5 to 1 micrometer. EcoliStreptococcus

 Some bacteria are autotrophs, to eat they  Capture the sun’s energy  Energy form chemical substances in their environment.  Some bacteria are heterotrophs, to eat they  Consume other organisms  Consume food other organisms make  Consume a variety of foods from milk and meat to decaying leaves.

 Respiration is the process of breaking down food to release its energy.  Most Bacteria need oxygen to break down their food,(Aerobic bacteria)  There are a few kinds of bacteria that few do not need oxygen(Anaerobic bacteria).

 When bacteria have plenty of food, the right temperature, and other suitable conditions they thrive and multiply quickly.  Bacteria can reproduce as often as every 20 minutes!  There are three types of bacterial reproduction.

 Asexual reproduction is a reproductive process that involves only one parent and produces offspring that are identical to the parent.  Bacteria reproduce by a form of asexual reproduction called binary fission.  Binary fission means one cell divides to form two identical cells.  Each bacteria has an exact copy of the parent cell’s genetic material

 Some bacteria under go simple sexual reproduction, which means two parents combine their genetic material to produce a new organism which is different from the parent cells.  This is called conjugation, when one bacterium transfers some of its genetic material into another bacterium through a thin, threadlike bridge that joints the cells. Figure 10 pg 52  The result is a new bacteria with a new combination of genetic material.

 Bacteria that live in harsh conditions use the process of forming endospores.  An endospore is a small, rounded, thick-walled resting cell that forms inside a bacterial cell.  It contains the cell’s genetic material and some cytoplasm  Because endospores can resist freezing, heating, and drying they can survive for many years, until if finds a suitable environment, then the bacterial opens up and multiplies.

 Most bacteria are harmless or helpful!  Bacteria are involved in oxygen and food production, environmental recycling and cleanup, and in health maintenance and medicine production.

 As autotrophic bacteria use the sun’s energy to produce food, they also release oxygen into the air.

 Cheese, sauerkraut, pickles, apple cider, milk, buttermilk, yogurt, sour cream all need bacteria.  Bacteria can cause food to spoil by breaking down the food’s chemicals.  Heat  Cold  Pasteruization

 Decomposers  Organisms that break down large chemicals in dead organism into small chemicals.  “Nature’s recyclers” breaking down dead leaves  Nitrogen-fixing bacteria  Live in soil  Help convert nitrogen gas from the air into nitrogen products that plants need to grow.

 Some bacteria cleanup oils spills in the ocean or gas that leaks into the soil under a gas station.

 Bacteria help you digest food!  Make vitamins for your body.  Take the place of disease causing bacteria  Scientist make medicine from bacteria  Human insulin