Viruses & Bacteria

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Viruses Bacteria

• Chapter 17
• Biology 11
• Presentation put together by Mandie Lynn Walls

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What are Viruses

• A virus is a non-cellular particle made up of
  genetic material and protein that can invade
  living cells.

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T4 Bacteriophage
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Herpes Virus
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Escherichia Coli Bacterium

• E. coli is a bacterium. That is a crude cell, it
  is not a virus because viruses are protein
  containers with DNA cores or RNA cores.

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E. Coli and the Bacteriophage

• What it looks like in real life

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The Structure Of a Virus

• Viruses are composed of a core of nucleic acid
• The Nucleic acid core is surrounded by a protein
  coat called a capsid
• The Nucleic core is either made up of DNA or RNA
  but never both

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Cycle of Lytic and Lysogenic
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Vaccines

• Viruses grown on chicken embryos are attenuated
  vaccines
• Another type of vaccine is made by heat killing
  the virus

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Retrovirus

• Change DNA into RNA.
• Example of a Retrovirus is HIV

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• A typical, "minimal" retrovirus consists of
• an outer envelope which was derived from the
  plasma membrane of its host
• many copies of an envelope protein embedded in
  the lipid bilayer of its envelope
• a capsid a protein shell containing
• two molecules of RNA and
• molecules of the enzyme reverse transcriptase

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Bacteria Cell
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Prokaryotes

• Cells that do not have a nucleus
• Exist almost every where on earth
• Grow in numbers so great you can see them with
  the unaided eye
• Are placed in either the Eubacteria or the
  Archebacteria Kingdoms
• Make up the smaller of the two kingdoms

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Eubacteria

• Make up the larger of the two prokaryote kingdoms
• Generally are surrounded by a cell wall composed
  of complex carbohydrates

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Cyanobacteria

• Photosynthetic bacterium
• Bluish-greenish color
• Contain membranes that carry out the process of
  photosynthesis
• Do not contain the same type of chloroplasts as
  plants do
• This bluish-greenish algae can be found nearly
  everywhere on earth.
• Can survive in extremely hot environments and
  even extremely cold environment

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Archaebacteria

• Lack important carbohydrate found in cell walls
• Have different lipids in their cell membrane
• Different types of ribosomes
• Very different gene sequences
• Archaebacteria can live in extremely harsh
  environments
• They do not require oxygen and can live in
  extremely salty environments as well as extremely
  hot environments.

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Identifying Prokaryotes

• Cell Shape
• Cell Wall
• Movement

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Bacterium Shapes

• Cocci Sphere shaped bacteria
• Bacillus Rod shaped bacteria
• Spirrillium Spiral shaped bacteria
• Flagella Leg-like structures that help to propel
  the bacterium.

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Gram and Gram Bacterium Cell Walls
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Cellular Walls

• Chemical nature of a cell wall can be determined
  by Gram Staining
• By finding out what color the cell produces when
  it is gram stained you can figure out the type of
  carbohydrates in the cell wall

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Movement

• Flagella Tail like structure the whips around
  to propel the bacterium
• Cillia Miniature flagella surround the cell
  that help to swim
• Non motile Sticky cillia like structures that
  keep the bacterium from moving

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Flagella
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Bacteria and their energy

• Autotrophs
• Chemotrophs
• Heterotrophs

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Autotrophs

• Make their own energy
• Using Solar energy
• Eg. Cyanobacteria

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Chemotrophs

• Make own Energy
• Using Chemical energy
• Eg. Archaebacteria

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Heterotrophs

• Obtain food
• By eating
• Eg. E-coli

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Bacteria Respiration

• Live without Oxygen
• Can live with or without oxygen
• Cannot live without oxygen.

• Obligate Anaerobes
• Facultative Anaerobes
• Obligate Aerobes

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Bacteria Reproduction

• Binary Fission
• Conjugation
• Spore Formation

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Cellular organism copies its genetic information
then splits into two identical daughter cells
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Conjugation

• A type of Bacteria Sex
• Two organism swap genetic information, that
  contains the information such as a resistance to
  penicillin

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Spore Formation Endospore

• A type of dormant cell
• Exhibit no signs of life
• Highly resistant to environmental stresses such
  as
• -High temperatures
• -Irradiation
• -Strong acids
• -Disinfectants
• Endospores are formed by vegetative cells in
  response to environmental signals that indicate a
  limiting factor for vegetative growth, such as
  exhaustion of an essential nutrient.

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Symbiosis

• Close relationship between to species in which at
  least one species benefits from the other
• Live together for LIFE

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Parasitism

• Bacteria exploit the host cell, injuring them
• Eg. Mychobacterium tuberculosis

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Mutualism

• Symbiosis in which two of the species live
  together in such a way that both benefit from the
  relationship
• Eg. E-coli

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Nitrogen Fixations

• Process by which nitrogen in the atmosphere is
  converted into a form that can be used by living
  things

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THE END
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