Bio 1215 Viruses
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(T)Why are viruses non-living?
- 1. No signs of life on its own , makes the host cell its slave
- 2. they cannot replicate on their own, need a host cell
- 3. genetic material surrounded by protein shell
- 4. No other cell would surveive chrstalization but viruses do thats why we consider them Non-living. All living cells would die
- 5. Has RNA, not living cells have RNA but viruses do
What are the 4 structural diversity of viruses
- 1. Tobacco Mosaic Virus
- 2. Adenovirus (causes a lot of cold symptoms)
- 3. Influenza Virus(Dangerous cause of double shell)**
- 4. Bacteriophage
(T)What do all viruses have in common?
- 1. Genetic material: either RNA or DNA
- 2. Capsid: a protein "shell" composed of spherical "subunits"(cappled capsomeres) FUNCTIONS to protect the genetic material from host or anything entering
What is the function of a capsid in viruses?
TO protect the genetic material from host or anything entering
What is the envelope in a virus?
Envelop is the "covering" of virsues that infect animal cells. The envelope is composed of the membrane of the host cella nd viral glycoproteins
(T)What is the function of the envelope in viruses?
- 1. It is composed of membrane of host cell and viral glycoproteins(made by virus)
- 2. Glycoproteins pick up envelope when it leaves the cell
- 3. It is dangerous because it has easy access into cell its going to infect
- 4. It buries itself in nucleus of cell so hard to tell if its infected
(T)Describe the structure of HIV
- 1. looks like influenza virus
- 2. has 2 strands of Identical RNA so it can multiply faster and as a backup
- 3. integrase - help insert genetic material in host cell
- 4. protease - make virus
- 5. reverse transcriptase - enzyme that converts RNA to DNA
- 6. envelope taht consists of viral glycoproteins and membrane of host cell
- 7. has capsid and phospholipid bi-layer
What are some ways someone can get HIV? Get infected?
- 1. Blood transfusions
- 2. Drug use(sharing needles)
- 3. vaginal/anal unprotected intercourse
- 4. breast milk
- 5. HIV in saliva but not strong enough to transfer
(T)How does HIV reduce the immune system of an infected person? Explain the steps of how HIV gets into the immune system
1. The envelope glycoproteins enable the virus to bind to specific receptors on certain whtie blood cells
2. The virus fuses with the cell's plasma membrane. The capsid proteins are removed(becomes capsomeres), releasing the viral proteins and RNA.
3. Reverse transcriptase catalyzes the synthesis of a DNA strang complementary to teh viral RNA.
4. Reverse transcriptase catalyzes the syntheis of a second DNA strand complementary to the first
5. The double-stranded DNA is incorporated as a provirus into the cell's DNA.
6. Proviral genes are transcribed into RNA molecules, which serve as a genomes for the next viral generation and as mRNAs for translation into viral protein.
7. The viral proteins include capsid proteins and reverse transcriptase (made in the cytosol) and envelope glycoproteins (made in the ER)
8. Vesicles transport the glycoproteins to the cell's plasma membrane.
9. Capsids are assumbled around viral genomes and reverse transcriptase molecules.
10. New viruses bud off from the host cell
What is T-lymphocyte
Group of white blood cells
(T)How does HIV virus take over genetic material?
Entergrase takes viral DNA and into the nucleus and cuts across DNA of t-lymphocyte and puts genetic material of virus into smack middle of DNA strand.
How do most people die from HIV?
From secondary causes.
- Ex. Parasitic infectino of digestive tract, kaposi's sarcoma
Parasitic worms usually won't harm anyone but since people with HIV has low immune system they can die from it.
Why are there no vaccines for AIDS?
The virus is constantly mutating
Why is HIV virus always mutating?
Because of reverse transcription(it makes errors = genetic material changing)
Why are antibiotics useless against HIV viruses?
Because antibiotics arget metabolic machinery but there is no chemical reaction in HIV so it would not work
What three factors slow down the progress of HIV disease? and How?
1. Reverse transciptase - Shuts off viral RNA from becoming DNA targeting reverse transcriptase
- 2. Protease inhibitors- targets protease which makes proteins
- 3. Harmless virus**
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