Transcript VIRUSES

VIRUSES
AND HIV
VIRAL VOCABULARY
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Bacteriophage
Pathogen
Lytic cycle
Lysogenic cycle
Prion
Viroid
Vaccination
Immunity
HIV– MODERN DAY PIRATE
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HIV – HUMAN IMMUNODEFICIENCY VIRUS
AIDS – ACQUIRED IMMUNE DEFICIENCY SYNDROME
3 AREAS SERIOUSLY AFFECTED – ASIA, S. AMERICA,
AFRICA
DRAW AND LABEL VIRUS
METHODS OF TRANSMISSION – BLOOD, SEMEN,
VAGINAL/CERVIAL SECRETIONS, BREAST MILK, PUS
TARGET CELL OF HIV –T HELPER CELL
RECEPTOR- CD4 on T HELPER CELL
OPPORTUNISTIC INFECTION – A NORMAL
HARMLESS ORGANISM THAT WHEN IT ENTERS THE
BODY OF A PERSON WITH A WEAK IMMUNE SYSTEM,
IT CAN HARM OR KILL THEM
HIV– MODERN DAY PIRATE
continued…
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WHERE IS THE VIRUS?
– Free in- Blood, semen, vaginal secretion,
breast milk
– Resident in- same as above plus pus
PORTALS OF EXIT- same as above
 HIV ENTRANCES- breaks in skin (mouth,
vagina, rectum, anywhere!); through
placenta
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ANATOMY- Lots of
Variety!
spikes
/DNA
* Must attach to a
specific receptor site
Viral Anatomy
Influenza Virus Strains
HIV – TIME COURSE TO AIDS
T-Helper Lymphocyte –
Target cell in the immune system
for HIV
CD4 Receptor – “Velcro”
a special receptor on a host cell's
surface that HIV uses to infiltrate
the cell
Reverse Transcriptase –
The enzyme produced by HIV and
other retroviruses (contain RNA)
that allows them to synthesize DNA
from their RNA.
HIV virus
attacking and
infecting a
Helper T-cell
Characteristics of Viruses…ARE
THEY ALIVE???
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REPRODUCTION!!!!!!! – they are good at it!
– Not by mitosis or meiosis
– Only when associated with another cell
 Obligate Intracellular Parasites –
microorganisms that can only reproduce if they
have entered another organism's cell
Non-cellular – no cytoplasm, no cell membrane
no digestion, no respiration, no movement
(without help)
 GENETIC MATERIAL – DNA or RNA
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How are new viruses produced?
See lab on Viral Replication
 The method slightly differs if the virus
contains DNA or RNA
DNA Virus:
The viral DNA is injected into the host cell. It
either becomes part of the host cell DNA or
remains free inside the cell. The host cell
produces viral RNA and proteins and
assembles new viruses.
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How are new viruses
produced?
RNA Virus: RETROVIRUS
1. Retrovirus injects its RNA into the host cell.
2. The RNA attaches to the host cell’s ribosomes
and new viral proteins are made- OR-…#3
3. The viral enzyme- REVERSE TRANSCRIPTASEconverts the viral RNA into DNA.
4. The newly formed DNA gets into the host cell’s
DNA and the host cell then produces new RNA
and proteins from it.
VIRAL REPLICATION LAB
LAB ANSWERS…
REPRODUCTION CYCLES
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LYTIC CYCLE –virulent (disease causing) –
active phase
1. Absorption – attachment to receptor site
2. Entry – insertion of genetic material
3. Replication – viral parts are made – capsid and
nucleic acids
4. Assembly – separate parts are put together
5. Release – digest cell membrane and escape
(destroys host cell in the process
LYSOGENIC CYCLE
Temperate virus – does not cause disease
immediately - virus hides out
 Resides in the cell without replicating. The
cell may divide and result in many cells with
the viral genetic material inside
 Will lead to lytic cycle eventually
 HIV spends the majority of the time in this
cycle
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Adenovirus
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A group of viruses that
infect the membranes
(tissue linings) of the
respiratory tract, the
eyes, the intestines, and
the urinary tract.
Adenoviruses account for
about 10% of acute
respiratory infections in
children and are a
frequent cause of
diarrhea.
V. Relatives of Viruses
Viroids – short strands of RNA, no capsid
 Prions – glycoproteins containing a polypeptide
of 250 amino acids.
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– A protein capable of replication
– Infectious protein…no nucleic acid
– Causes Mad Cow disease, scrapies in sheep, and
Kuru in New Guinea
Pictures
VIROIDS
PRIONS
MAD COW DISEASE (BSE)
Fore people of New Guinea
VI. VACCINES –
preventions…not a cure
Immune System – responds to foreign proteins
(bacteria, virus, organ transplant, blood
transfusion, bee venom, peanuts, pollen) –
fever, swelling, increased mucus secretions,
allergies…etc.
 Inoculation – injection with
a non-replicating virus or
viral parts
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Antibodies – formed by the body to the
specific foreign protein and seeks to destroy
them…why you cannot get sick with the same
cold twice
 Antibodies continue to be produced indefinitely
and remain to protect in the event of a second
exposure to the real disease causing virus
 Immunity – your body mounting a response
against a foreign antigen protein...attacks and
destroys the foreign substance
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QUIZ TOPICS
HIV/AIDS, Video stuff
 Text 450-459, 942-943, 939, 1018-1020
 Vocab
 Living/Nonliving WS
 Lab on Reproduction
 Anatomy, Reproduction, Immunity, prion
vs. viroid, vaccines
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Jeopardy Questions - Easy
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HIV Stands for….
Your immune system responds to ______.
How soon after exposure to HIV are you
infectious?
Define obligate intracellular parasite.
Name 3 diseases caused by viruses.
What is an opportunistic infection?
Why would a virus be considered nonliving?
What is the target cell for HIV?
Jeopardy Questions - Medium
What is the main difference b/t prion and
a viroid?
 Name 3 non-sexual fluids that carry HIV?
 What do AIDS victims typically die from?
 AIDS stands for?
 What part of the virus attaches itself to
the host cell?
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Jeopardy Questions - Difficult
What does the AIDS test really test for?
Why is it not accurate for up to 6 months?
 How does a vaccine work?
 Contrast lytic vs. lysogenic cycle.
 What is the function of the reverse
transcriptase enzyme?
 Name the 3 places most seriously affected
by AIDS (globally).
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