1. 7.2 Bacteria Key Concepts:
How do the cells of bacteria differ from those of eukaryotes?
What do bacteria need to survive?
Under what conditions do bacteria thrive and reproduce?
What positive roles do bacteira play in people’s lives?
Key terms:
Bacteria, flagellum, binary fission, asexual reproduction, sexual reproduction, conjugation, endospore, pasteurization, decomposer

2. Bacterial Cell
Anton van Leeuwenhoek found cells by accident. He liked microscopes and was lookin’ at stuff. He thought they looked like monks’ chambers so he called them cells.
He also saw some tiny worm like stuff but he didn’t know what they were
Now we know they were bacteria (prokaryotes. Their genetic material is not contained in a nucleus)

3. Cell structure Cell structures
Most bacterial cells lack mitochondria and golgi bodies.
They are surrounded (like plant cells) by a rigid cell wall. Just inside the cell wall is the cell membrane.
They also have cytoplasm and ribosomes and genetic material (which looks like a string)
Flagellum – long whiplike structure that helps a cell move. It spins in place like a propeller. They may have one or more. Not all bacteria have flagella.

4. Cell sizes Bacteria vary greatly in size
The largest known bacterium is about as large as a period (.), but the average is much smaller than that (usually a micrometer or 1 millionth of a meter in size)

5. Cell shapes Most are of 3 basic shapes: spherical, rodlike, or spiral.
The chemical makeup of the cell wall determines shape

6. Obtaining food and energy
Some bacteria are autotrophs
They make food by using the sun’s energy OR chemicals they find around
Some bacteria are heterotrophs
They consume other organisms or the food that other organisms make

7. Respiration
Energy comes from breaking down food in the process of respiration. Some need oxygen, some don’t.

8. Reproduction
When bacteria have plenty of food, the right temperature, and other suitable conditions, they thrive and reproduce frequently.

9. Asexual reproduction
Bacteria reproduce by binary fission – one cell divides to form two identical cells
First a cell duplicates its genetic material then it divides it into new identical separate cells
Asexual reproduction – involves only one parents and produces offspring that are identical to the parent.

10. Sexual reproduction Sexual reproduction- some bacteria “do it”
Parents combine their genetic material to produce a new organism which differs from both parents
Conjugation – one bacterium transfers from genetic material to another bacterium through a threadlike bridge. After the transfer, they separate.
It results in bacteria with a new combination of genetic material . This passes to the offspring. It DOES NOT increase the number of bacteria, but it DOES result in genetically different bacteria.

11. Endospore formation
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 of its cytoplasm.
They help bacteria survive harsh conditions b/c they can resist freezing, heating, and drying.
They are also light – so a breeze can carry one to new places, then it opens up and the bacterium grows and multiplies.

12. The role of bacteria in nature
Bacteria are involved in oxygen and food production, also in health and medicine
Oxygen: autotrophic (self-feeder) bacteria use the sun’s energy to release oxygen into the air
Food: yogurt, apple cider, cheeses all use bacteria

13. Pasteurization
Food is heated to the point where the temp is high enough to KILL bacteria muahahahahahaaaaaa

14. Environmental recycling
Decomposers – organisms that break down large chemicals in dead organisms into small chemicals
They are “nature’s recyclers”
Some are “nitrogen fixing” – live in the soil and convert nitrogen gas into stuff plants need
Environmental clean-up: Some bacteria eat oil and other nasty stuff

15. Health bidness
Bacteria are all up in your bidness. They keep your digestive system healthy, for example. They also make vitamins that you need.
Insulin – can be made by genetically engineered bacteria for people with diabeetus (diabetes).