1 Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal CellPlant Cell Bacterial Cell

2  Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles  Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals) Cells May be Prokaryotic or Eukaryotic copyright cmassengale

3 Prokaryotes Most numerousMost numerous organisms on Earth bacteriaInclude all bacteria Earliest fossils dateEarliest fossils date 2.5 billion years old

4 Characteristics of Bacteria

5 Bacteria can have Different shapes

6 Bacillus - E. coli

7 Staphylococcus

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9 Bacterial Structure Microscopic prokaryotesMicroscopic prokaryotes unicellularunicellular No nucleus or membrane- bound organellesNo nucleus or membrane- bound organelles Contain ribosomes – make proteinsContain ribosomes – make proteins Single, circular chromosome in nucleoid region - DNASingle, circular chromosome in nucleoid region - DNA

10 Bacterial Cell

11 Protection Cell Wall made of PeptidoglycanCell Wall made of Peptidoglycan May have a sticky coating called the Capsule for attachment to host or other bacteriaMay have a sticky coating called the Capsule for attachment to host or other bacteria

12 Sticky Bacterial Capsule

13 Flagella Bacteria that are motile have appendages called flagellaBacteria that are motile have appendages called flagella A bacteria can have one or many flagellaA bacteria can have one or many flagella

14 MonotrichousLophotrichous AmphitrichousPeritrichous

15 Pili Short protein appendagesShort protein appendages Smaller than flagellaSmaller than flagella Adhere bacteria to surfacesAdhere bacteria to surfaces Used in conjugation for Exchange of genetic informationUsed in conjugation for Exchange of genetic information

16 Pili in Conjugation

Bacteria Replication 17 Binary fission Conjugation Use pilus

18 Bacteria Most grow best at pH of 6.5 to 7.0Most grow best at pH of 6.5 to 7.0 Large portion of bacteria are usefulLarge portion of bacteria are useful Only some cause disease Only some cause disease

19 Useful Bacteria Some bacteria can degrade oilSome bacteria can degrade oil Used to clean up oil spillsUsed to clean up oil spills Act as decomposers – nitrogen cycleAct as decomposers – nitrogen cycle

20 Useful Bacteria Other uses for bacteria include making yogurt, cheese, and buttermilk.Other uses for bacteria include making yogurt, cheese, and buttermilk.

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E. Coli = Gram Negative Bacillus = Gram Positive 24

BIOFILM The plaque that forms on teeth and causes tooth decay Form when bacteria adhere to surfaces and secrete a slimy, gluelike substance Forms communities of disease causing bacteria Biofilms can form anywhere – clogged drains, slippery rocks ect.. 25

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How Antibiotics Work Interferes with cell wall – loses protections Interferes with the bacteria’s ability to make proteins Interferes with the ability to replicate DNA 27

28 Zone of inhibition

INQUIRY LAB Test different types of mouthwash to determine which type kills the most bacteria. Use the principles of antibiotic testing Determine procedure – lab writeup –Purpose, hypothesis, materials, procedure, data, analysis, conclusion Decide which two types of mouthwash you will test Measurements – zone of inhibition Come to a conclusion 29

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