1. What are the two kingdoms that contain bacteria?
Archaebacteria “The extremists”
Eubacteria “Found everywhere”

2. Section 18.2 Summary – pages 484-495
Bacteria
A bacterial cell is a very small prokaryotic cell.
Although tiny, a bacterial cell possesses all the characteristics of life.
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3. Section 18.2 Summary – pages 484-495
Ribosomes (makes proteins)
Plasma Membrane Inner-most layer
Flagella (helps it move) not all bacteria have this
Cell Wall Middle layer
Capsule (outer-most layer) not all bacteria have this
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4. Section 18.2 Summary – pages 484-495
Bacterium Structure
A bacterial cell remains intact (together) as long as its cell wall is intact.
If the cell wall is damaged, water will enter the cell by osmosis, causing the cell to burst.
Scientists used a bacteria’s need for an intact cell wall to develop a weapon against bacteria that cause disease.
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5. Section 18.2 Summary – pages 484-495
Antibiotics
In 1928, Sir Alexander Fleming accidentally discovered penicillin, the first antibiotic—a substance that destroys bacteria.
He had been looking at bacteria under the microscope. He left the dirty slides in the sink, and a mold began to grow on them. He later noticed that the mold was killing the bacteria.
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6. Section 18.2 Summary – pages 484-495
Antibiotics
Later, biologists discovered that penicillin can destroy the cell walls of bacteria.
When bacteria are put in penicillin, holes develop in their cell walls, water enters their cells, and they rupture and die.
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7. Unfortunately, antibiotics kill both good and bad bacteria.
You have good bacteria that live in your intestine that help you digest food.
Eating foods that contain these good bacteria while you are taking an antibiotic can help keep and/or replenish your body’s supply…yes, the above foods contain LIVING good bacteria.

8. Section 18.2 Summary – pages 484-495
Identifying Bacteria
One trait that helps classify bacteria is how they react to Gram stain.
Gram staining is a technique that stains bacteria a certain color, which lets doctors/scientists know what kind of cell wall the bacteria possess This helps doctors decide which antibiotics to use.
GRAM POSITIVE
GRAM NEGATIVE
Stain purple- thicker cell wall
Stain pink- thinner cell wall
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9. Section 18.2 Summary – pages 484-495
Identifying Bacteria
Bacterial cells often grow in characteristic patterns that provide another way of categorizing them.
Diplo–is a prefix that refers to bacteria that pair up.
The prefix Staphylo–describes an arrangement of cells that resemble grapes.
Strepto–is a prefix that refers to an arrangement of chains of cells.
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10. Section 18.2 Summary – pages 484-495
Bacterium Shapes
The three most common shapes are:
Spheres, called “coccus”
Rods, called “bacillus”
Spirals, called “spirillum”
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11. 1. The above bacteria stained a dark purple
1. The above bacteria stained a dark purple. What does that tell you about this bacteria?
Strong/Thick cell wall
2. The above bacteria grows in chains and the cells are round. What is the name of this bacteria?
Strepto-coccus

12. Section 18.2 Summary – pages 484-495
Bacteria Reproduction
Bacteria reproduce asexually by a process known as binary fission.
Basically, it is mitosis for a bacterial cell. The end result is two identical bacterias.
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13. Section 18.2 Summary – pages 484-495
Bacteria Reproduction
Under ideal conditions, some bacteria can reproduce every 20 minutes, producing enormous numbers of bacteria quickly.
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Bacteria Reproduction
Some bacteria communicate in a process called conjugation.
During conjugation, one bacterium transfers all or part of its chromosome to another bacteria through or on a bridge-like structure called a pilus that connects the two cells.
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Survival Mechanism
Some bacteria, when faced with unfavorable environmental conditions, produce a tiny “escape pod” called an endospore.
An endospore is a tiny structure that contains a bacterium’s DNA and a small amount of its cytoplasm, encased by a tough outer covering that resists drying out, temperature extremes, and harsh chemicals.
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Survival Mechanism
As an endospore, the bacterium rests and does not reproduce.
Endospores can survive a temperature of 100˚C, which is the boiling point of water.
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17. Section 18.2 Summary – pages 484-495
GOOD BACTERIA
IN YOUR BODY
• Trillions of “good” bacteria live in your body Most are found in your intestinal tract.
Write what is in blue and underlined
Lactobacillus acidophilus
• It protects intestines, helps aid in digestion, helps build immunity to food allergies, and lowers blood cholesterol.
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18. Section 18.2 Summary – pages 484-495
GOOD BACTERIA
Makes Some Foods and Medicines
Some foods that you eat—mellow Swiss cheese, crispy pickles, vinegar, sauerkraut, and tangy yogurt—would not exist without bacteria.
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GOOD BACTERIA
Makes Some Foods and Medicines
In addition to food, some bacteria produce important medicines.
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GOOD BACTERIA
Help with Farming
Remember, bacteria help convert nitrogen in the soil so that plant’s can use it and grow better!
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21. GOOD BACTERIA Recycle Nutrients
Life could not exist if bacteria did not break down decomposing organisms and return the nutrients to the environment.

22. Form groups of two or three
We will use an agar dish to grow bacteria.
Agar is a jelly-like polysaccharide where certain cells can grow. It’s a “food” for the bacteria.