Download Bacteria and Viruses

Bacteria and Viruses
Viruses
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What makes something ALIVE?
Maintains homeostasis.
Reproduction
Cellular organization
Metabolism
Contains Genetic Information
Are viruses ALIVE?
Viruses do reproduce and contain genetic information.
Viruses do not break down food, grow or move.
Viruses are helpless without living cells! Viruses need to live in other
cells called “host cells” so that they can reproduce!
VIRUSES ARE NOT ALIVE!!!
Viruses are made up of nucleic acid surrounded by one or two protein
coats.
I. Viruses
-Viruses are non-living
particles.
-They have a nucleic acid
core and a protein
containing capsid.
Viruses
-Viruses need a host cell in order
to make more viruses.
Diseases caused by viruses
-Many diseases are caused by viruses including:
Common cold, flu, small pox, warts and HIV.
How can you get a virus?
Airborne
Contaminated blood
products
Infected Animals or Vectors such as Mosquitoes
Contaminated food
or water
Sexual contact
II. Bacteria
-There are two kinds of bacteria:
1. Archaebacteria-live in extreme environments
(ex: hot springs, cold mountains).
2. Eubacteria-live everywhere else (ex: our bodies,
food).
Bacteria
-Bacteria are small, one-celled prokaryotes.
-Bacteria reproduce asexually by binary fission.
Bacteria
Structure of Bacteria:
-All bacteria have a cell wall.
-Bacteria are surrounded by a
capsule which keeps them from
being eaten by white blood cells.
-Only bacteria that have capsules
are infectious (can cause disease).
Bacteria
Bacteria
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1. Bacteria come in 3 shapes
a. cocci-spheres
b. bacilli-rods
c. spirilli-spirals
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2. Bacteria can be arranged in 3 ways
a. Diplo-paired
b. Staphylo-grapelike clusters
c. Strepto-long chain
3. Bacteria can live with or without oxygen
a. Aerobes-need oxygen (O2)
b. Anerobes-don’t need oxygen (O2)
Bacteria shapes
Streptococci
Diplobacillis
Streptospirilli
Bacteria
-Bacteria are all around us. Not all bacteria cause
disease-we have bacteria that live in our
stomachs that actually keep us healthy!
-Some bacteria do cause diseases such as Strep
Throat, pneumonia, diphtheria.
Bacteria
-Penicillin kills bacteria by
making holes in the cell
wall. Water then enters
the cell by osmosis, and
the cells explode and die.