Download What are Viruses ?

What are Viruses ?
A virus is a nonnon-cellular particle made up
of genetic material and protein that can
invade living cells.
cells
Some examples areare- Rabies virus, HIV
Aids virus, Herpes virus
Herpes Virus
Rabies Virus
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
p
capsid
The Nucleic core is
either made up of
DNA or RNA but
never both
b h
HIV/AIDS
HIV/
HIV is the virus that causes the syndrome
syndrome,
AIDS
HIV = “Human
Human Immunodeficiency Virus”
Virus
AIDS = “Acquired
“Acquired Immune Deficiency
S d
Syndrome”
”
HIV/AIDS
1981 - First cases of AIDS
1983 - Virus
Vi
id
identified
tifi d
The number of infected people worldwide
continues
ti
tto grow att an alarming
l
i rate
t
OH MY GOSH!!!
Florida is #3 in the nation for AIDS cases
Palm Beach County is #6 in AIDS
cases.
cases
What is looks like:
HIV attacks our Immune System
1. Virus ((antigen)
g ) enters the body
y
2. Macrophages find the virus and call the
lymphocytes to help
3. Helper T lymphocyte cells signal B cells to make
antibodies to kill antigen.
4 HIV iinfects
4.
f t the
th Helper
H l
T cells
ll changing
h
i th
them tto
HIV making factories
5 T cells now can’t
5.
can t protect you,
you and a bunch of
other infections take over your body
“Opportunistic Infections”
Exactly What Happens?
ENTRY
„
„
HIV enters through break in skin barrier
Virus targets T4 cells because they have a special
protein on their membranes that fit the HIV virus
envelope
Transcription
„
„
„
„
„
HIV leaves protein coat and HIV capsid enters T4 cell
Releases RNA and enzyme reverse transcriptase for
transcritption
Enzyme causes cell to create complimentary DNA
strand from
f
HIV RNA
Inserts itself into the T cell DNA
Can remain inactive for up
p to 8 yyears
Exactly what Happens Con’t
Con t
Translation and Assembly
„
Once activated, HIV DNA uses T4 cell machinery to
make more HIV RNA and protein coats.
Lysis
„
„
New HIV bud out of original T4 cell and infect other
T4 cells.
ll N
Now, th
the T4 cells
ll can’t
’t signal
i
l B cells
ll tto
make antibodies because too many are infected.
Immune System is very weak and can’t
can t even fight the
smallest infections.
Death
People do not die of AIDS
(it is a SYNDROMESYNDROME- NOT A DISEASE)
They die from the opportunistic infections