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.

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Introduction to CellsCells are the basic units of

organismsCells can only be observed under

microscopeBasic types of cells:

Animal Cell Plant CellBacterial Cell

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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

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Prokaryotes

• Most numerous organisms on Earth

• Include all bacteria

• Earliest fossils date 2.5 billion years old

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Characteristics of

Bacteria

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Bacteria can have Different shapes

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Bacillus - E. coli

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Staphylococcus

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Bacterial Structure

• Microscopic prokaryotes

• unicellular• No nucleus or

membrane-bound organelles

• Contain ribosomes – make proteins

• Single, circular chromosome in nucleoid region - DNA

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Bacterial Cell

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Protection

• Cell Wall made of Peptidoglycan

• May have a sticky coating called the Capsule for attachment to host or other bacteria

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Sticky Bacterial Capsule

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Flagella• Bacteria that are

motile have appendages called flagella

• A bacteria can have one or many flagella

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Monotrichous Lophotrichous

Amphitrichous Peritrichous

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Pili• Short protein appendages

• Smaller than flagella

• Adhere bacteria to surfaces

• Used in conjugation for Exchange of genetic information

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Pili in Conjugation

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Bacteria Replication

Binary fission

ConjugationUse pilus

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Bacteria

• Most grow best at pH of 6.5 to 7.0

• Large portion of bacteria are useful

• Only some cause disease

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Useful Bacteria

• Some bacteria can degrade oil

• Used to clean up oil spills

• Act as decomposers – nitrogen cycle

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Useful Bacteria

• Other uses for bacteria include making yogurt, cheese, and buttermilk.

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• E. Coli = Gram Negative

• Bacillus = Gram Positive

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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..

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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

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Zone of inhibition

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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

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