Download What is a Microbe?

What is a Microbe?
Microscopic organisms that exist
as single cells or cell clusters.
Too small to be seen w/out a
microscope.
Classified into 2 Categories
 Prokaryotes:
organisms that do NOT
have a membrane-enclosed nucleus.
Ex) Bacteria
 Eukaryotes: contain membraneenclosed organelles such as a nucleus.
Ex) Animal Cells and Protists
Viruses
 Tiny
NON-LIVING particle that enters
and then reproduces inside a living
cell.
 Considered to be NON-LIVING
because they are not cells and cannot
make or take in food.
Size of Viruses
Structure of a Virus
 All
viruses have 2 basic parts: a protein
coat that protects the virus and an inner
core made of genetic material.
 Come in different shapes.
Filovirus
 Do
not have a
distinct, uniform
shape
 Ex)Ebola
Polyhedral Virus
 Geometric
appearance, look
like crystals
 Ex) Polio
Envelope With Projections
 Spherical
shape
with projections
 Ex) Flu, HIV
Bacteriophage
 Resembles
a
spacecraft.
Attacks only
bacteria
 Ex) E.coli
How Viruses Multiply
 Although
viruses can multiply, they do
so differently than organisms. Viruses
can multiply ONLY when they are
inside a living cell.
 Host: organism that provides a source
of energy for a virus or another
organism.
 Parasite: an organism that lives on or
inside a host and causes it harm.
How Viruses Multiply
 Once
inside a cell, a virus’s genetic
material takes over many of the cell’s
functions.
 It instructs the cell to produce the
virus’s proteins and genetic material.
 The proteins and genetic material then
assemble into new viruses.
Active v. Hidden
 Active
viruses
 Hidden viruses
enter cells and
“hide” for a
immediately
while inside host
begin to multiply
cells before
leading to the
becoming active.
quick death of
the invaded cells.
Active Virus
Hidden Virus