Download Viruses - Mrs. Simmons` Biology

Viruses
Viruses:
-NONLIVING (not made
of cells)
-Smaller than Prokaryotes
(bacteria)
-Able to reproduce
rapidly (only in
host cell)
Viruses consist of:
-Capsid-Protein Coat (helps
virus enter cells)
-RNA or DNA
What do Viruses look like?
Tailed phages
Viruses may attack:
-Eukaryotes (plant or animal)
-Prokaryotes
called Bacteriophages
Uses the host’s organelles
to replicate (copy)
 Illnesses caused by viruses
 Common cold
 Flu
 AIDS
 Bird flu
 Polio
HIV
Smallopx virus
Aeromonas virus 31
Herpes simplex virus
Electron micrographs of viruses.
Influenza virus
Orf virus
Viruses:
Bind to specific host cell
before it can enter it
(lock and key)
Can plant viruses infect animals?
How Viruses Replicate1) Lytic Cycle- destroys host
cell quickly
OR
2) Lysogenic Cycle- its DNA
becomes part of host cell
and tells it to replicate (like
a Zombie Cell)
Common Viruses
Influenza (flu)
Spread by:
1) Direct Transmission (sneeze/cough
directly into eyes, nose mouth)
Common Viruses
Human Immunodeficiency Virus (HIV)
HIV
Specific to “Helper” T Cell
(T-Cells help the immune system
respond to different pathogens
like bacteria/viruses)
Kills “Helper” T Cells
-eventually destroying Immune
System
HIV
Transmitted 4 ways:
-Sexually
-Contaminated Needles
-Infected blood
-Breast milk
-At birth (mother to baby)
HIV
After years of battling HIV,
body becomes unable to fight
off infections and person will
have developed Acquired
Immune Deficiency Syndrome
(AIDS)
HIV & AIDS
Not virus or disease that
eventually kills the person–
inability to fight off anything,
including the common cold