Transcript VIRUSES

VIRUSES
AND HIV
VIRAL VOCABULARY
Bacteriophage
Read (942-943)
 Pathogen
Vaccinations(939)
 Lytic cycle
STDs
(1018-1020)
 Lysogenic cycle
 Prion
 Viroid
 Vaccination
Immunity

I. ANATOMY
spikes
/DNA
* Must attach to a
specific receptor site
DRAW AND LABEL
DRAW AND LABEL
Viral Anatomy
DNA or RNA
Contractile
Sheath
Influenza Virus Strains
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.
II. ARE THEY ALIVE???
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Obligate Intracellular Parasites – must get
inside a host to function
 Non-cellular – no cytoplasm, no membrane
 No digestion, respiration, movement
 REPRODUCTION!!!!!!! – they are good at it!
– Not by mitosis or meiosis
– Only when associated with another cell
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GENETIC MATERIAL – DNA or RNA
III. HOW DO THEY WORK?
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1.
See lab on Viral Replication
DNA vs. RNA VIRUS
DNA (after invasion)
Joins host DNA and produces viral RNA and
viral proteins
or
2.
Remains free and produces viral RNA and viral
proteins
HOW DO THEY WORK (cont.)
RNA – Retrovirus
 Usual flow of information – DNA>RNA>Protein
 Retroviruses – RNA>DNA>into our cells DNA –
uses reverse transcriptase (RT)
 Join ribosomes in cytoplasm and produce viral
proteins
OR
 With the help of RT, RNA makes DNA, which
gets into the host cell’s DNA – new RNA is
produced and acts as above
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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 AN LABEL VIRUS
METHODS OF TRANSMISSION – BLOOD, SEMEN,
VAGINAL/CERVIAL SECRETIONS, BREAST MILK, PUS
TARGET CELL OF HIV – CD4+ 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 – TIME COURSE TO AIDS
Obligate Intracellular
Parasite – microorganisms
that can only reproduce if they
have entered another
organism's cell - all viruses
CD4 Receptor –
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 that allows them
to synthesize DNA from their RNA,
which is then integrated into the
chromosomes of the host cell.
T-Helper Lymphocyte –
target cell in the immune system
for HIV
HIV virus
attacking and
infecting a
Helper T-cell
IV. REPRODUCTION
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LYTIC CYCLE – REPRODUCTIVE CYCLE OF
THE VIRUS – 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 spend the majority of the time in this
cycle
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VIRAL REPLICATION LAB
LAB ANSWERS…
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, scrappies in sheep,
and Kuru in New Guinea
Pictures
VIROIDS
PRIONS
MAD COW DISEASE (BSE)
During WWII
Sheep parts were cooked and mixed in
cow feed
 Cooking didn’t destroy “scrapie” prion
 Cows were infected with prion
 Cows get BSE “mad cow” disease
 Can it be passed to humans?
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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…this is 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 - Easy
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HIV Stands for…. HUMAN IMMUNEDEFICIENCY VIRUS
Your immune system responds to FOREIGN PROTEINS
How soon after exposure to HIV are you infectious?
IMMEDIATELY
Define obligate intracellular parasite. MUST LIVE IN A
HOST TO SURVIVE AND REPRODUCE
Name 3 diseases caused by viruses. MEASELS, MUMPS,
RABIES, HIV, FLU, COLD, SMALL POX, CHICKEN POX
What is an opportunistic infection? ONLY HARMS WHEN
IMMUNE SYSTEM IS WEAK
Why would a virus be considered nonliving? NONCELLULAR
What is the target cell for HIV? T-HELPER LYMPHOCYTE
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 - Medium
What is the main difference b/t prion and a
viroid? PROTEIN VS. RNA STRAND
 Name 3 non-sexual fluids that carry HIV?
MOTHER’S MILK, BLOOD, PUS
 What do AIDS victims typically die from?
OPPORTUNISTIC INFECTIONS
 AIDS stands for? ACQUIRED
IMMUNEDEFICIENCY SYNDROME
 What part of the virus attaches itself to the
host cell? TAIL FIBERS
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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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Jeopardy Questions - Difficult
What does the AIDS test really test for?
ANTIBODIES Why is it not accurate for up to 6
months? TAKES THAT LONG FOR ENOUGH TO
BE PRODUCED
 How does a vaccine work? EXPOSE YOU TO A
NON-INFECTIOUS FORM OF THE
ORGANISM AND CAUSE YOUR IMMUNE
SYSTEM TO MAKE ANTIBODIES
IF YOU
ARE EXPOSED LATER YOUR BODY IS READY
 Contrast lytic vs. lysogenic cycle.
 What is the function of the reverse
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Contrast lytic vs. lysogenic cycle. LYTIC IS
THE IMMEDIATE REPLICATION OF
THE VIRUS
 What is the function of the reverse
transcriptase enzyme? CONVERT RNA TO
DNA
 Name the 3 places most seriously affected
by AIDS (globally). AFRICA, S and Central
America, Asia and SE ASIA
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A COUPLE MORE QUESTIONS
Give 3 reasons why some one may say that a
virus is alive.
2. Why can’t a doctor prescribe antibiotics for a
virus?
3. Describe the brief history of Mad Cow Disease
1.