Transcript Powerpoint Presentation of Viruses, HIV, & AIDS

Viruses consist of nucleic acids &
proteins.
Viruses replicate, but need a host
cell in order to do so.
1. Living things consist of cells
2. Cells are made up of complex
compounds: proteins, lipids,
carbohydrates, & nucleic acids
3. Living things reproduce
Viruses don’t grow, develop, or
carry out respiration
4. Living things grow & develop
Viruses are not cells (no membrane 5. Living things convert energy &
or cytoplasm)
carry out metabolism
Viruses have a
protein coat called
a capsid
The capsid encases
nucleic acid
(DNA or RNA)
Viruses may have
spikes
Viruses may have
an envelope that
consists of part of
cell membranes
Viruses are very
small (< 1mm)
Virus binds to membrane of host cell
Virus injects its nucleic acid into the host cell
Host cell makes viral DNA & viral proteins
New viruses assembled from proteins &
nucleic acids
Host cell releases new viruses
No, viruses are technically not considered living things.
Viruses do not carryout metabolic reactions like
respiration or photosynthesis. They don’t convert energy
Viruses are unable to reproduce or replicate on their own
VIRUSES ARE NOT CELLS…THEY DO NOT HAVE A
MEMBRANE & CYTOPLASM
Viruses are non-living particles that consist of
fragments of cells (protein & nucleic acid)
Viruses are less than 1 mm in size
Viruses are able to replicate, but
need to do so in a “host cell”
Sugar / Protein Spike
in Envelope Called a
Glycoprotien (gp 120)
Matrix Protein
Capsid (P 17 &
P 24) surrounds
RNA
Lipid Envelope
from membrane
of infected cells
Reverse
Transcriptase
enzyme attached
to RNA
100 nm diameter
HIV Binds to Immune Cells:
gp 120 locks to cell’s CD4 protein
HIV injects RNA into CD4 cell.
Reverse transcriptase produces DNA from
RNA.
Viral DNA embeds in cell’s DNA in
nucleus
Cell’s DNA Produces viral RNA
and proteins
Viral proteins & RNA assemble
into new virus at the membrane
Virus buds at membrane. Part of CD4
cell membrane becomes viral envelop.
Acquired Immune Deficiency Syndrome
When the immune system is
lacking one or more of its
components, the result is an
immunodeficiency disorder.
AIDS is an immunodeficiency
disorder caused by a virus that
destroys helper T cells and that is
harbored in macrophages as well
as helper (T4) T cells.
The AIDS virus splices its DNA
into the DNA of the cell it infects;
the cell is thereafter directed to
churn out new viruses.
HIV infects the vulnerable CD4
cells and replicates at a high
rate within these cells. As the
number of infected cells
increases, the destruction of the
immune system progresses.
The rate of viral replication in
productively infected CD4 cells
is extremely high (one billion
viral particles are produced
every day).
The immune system controls the infection by
producing vast numbers of T helper cells.
The battle between the viral infection and the
cells of the immune system continues.
Eventually the virus' ability to damage the immune system exceeds the body's
capacity to fight HIV.