Exam 4 (FINAL) Flashcards
How many cells make up the body?
50-100 trillion
What cells does the influenza virus affect?
Cells in the respiratory tract
What cells does the avian influenza virus affect?
Cells in the digestive system of birds
How do influenza virus cells affect respiratory tract cells?
Virus cells bind to respiratory cells, replicate, and then get out and spread
How does the avian influenza affect humans?
It recognizes cells in the lower part of the respiratory tract (lungs) and will most likely kill humans
What is the relationship between virus and patient?
Commensialistic symbiotic relationship
What is the basic structure of a virus?
Genome, Protein Shell (Capsid), Membraneous Envelope (phospholipid bilayer), some have glycoproteins on the envelope (H&N)
How does RNAi act as a viral defense mechanism?
It recognizes dsRNA and destroys it
What is the viral structure of a tobacco mosaic virus?
RNA in a capsomere of capsid
What is the viral structure of adenoviruses?
Hexagonal shaped capsomere containing DNA inside and surrounded by glycoproteins on the exterior
What is the viral structure of influenza viruses?
Circular membranous envelope with glycoproteins on the exterior. Contains capsids and RNA
What is the viral structure of bacteriophages?
Has a head containing DNA, tail sheath, and tail fiber
What kind of viral structure infects E. Coli?
Bacteriophage
What are the steps of the viral replicative cycle?
ss virus finds the cell with its glycoproteins. It binds to the surface of the host cell, and the viral contents end up in the host cell. The viral genome comes in and uses the cell’s transcription machinery to make viral proteins and replicate viral DNA. The newly formed virus exits to infect other cells.
What are the steps of the Lytic Cycle?
Infection of host cells. The infected cell synthesizes viral genome, protein (capsid), and other viral components. The host cell lyses (disintegrates) and releases particles.
What are the steps of the Lysogenic Cycle?
Infection of host cells. Viral DNA integrates into host DNA. Every time the host cell divides, the virus genome also replicates.
What is the class and genome of varicella (chicken pox)?
Herpesvirus. dsDNA
What is the class and genome of the influenza virus?
Orthomyxovirus. ssRNA
What is the class and genome of HIV?
Retrovirus. ssRNA
What has the lowest rate of mutagenesis?
Chicken pox because our human enzyme replicates dsDNA accurately
What has the highest rate of mutagenesis? Why?
HIV. It uses reverse transcriptase which makes more mistakes.
Why does influenza have a high rate of mutagenesis?
It uses RNA dependent RNA polymerase, and the influenza protein lacks the ability to correct errors.
What are the components of HIV?
ssRNA. Capsid protein. Viral envelope with glycoproteins. Reverse transcriptase.
cells in your body that put out CD4 proteins, HIV virus targets these cells as hosts
helper T cells
How does HIV replicate?
Once the virus is in the cell, it unloads two sRNA, reverse transcriptase, integrase, and protease. Virus uses reverse transcriptase to make DNA from RNA then integrates it into the cell’s DNA. Cell replicates, replicating viral DNA as well. mRNA is made from this DNA which now codes for viral proteins. Protease cleaves the viral proteins apart, and the peptide cleavage produces mature viral proteins.
How does one acquire AIDS?
Generation 2 of viruses attack other helper T cells (but some are killed by antibodies). Defense cells in the lymph system are attacked and depleted over time. Death by opportunistic infection.
What does AIDS stand for?
Acquired Immunodeficiency Syndrome
What are four strategies for AIDS treatment?
Inhibit HIV fusion and entry. Inhibit reverse transcriptase. Inhibit Integrase (prevent the incorporation of viral DNA into the host genome). Inhibit viral peptide processing.
How do HIV protease inhibitors help in AIDS treatment?
HIV protease inhibitors block the activity of HIV enzyme that alter viral proteins and convert them to their active forms
How do vaccines work?
stimulate natural immunodefense system before infection with inactivated toxins, weakened or dead microbes
Highly contagious respiratory infection that enters the body through mucus membranes in the mouth, nose, or eyes
Influenza (the flu)
respiratory disease of pigs caused by type A influenza viruses that cause regular outbreaks in pigs
swine flu
caused by influenza viruses that occur naturally among wild birds but is DEADLY to humans
Avian flu
human flu that causes a global outbreak of serious illness
Pandemic flu
influenza which most people have some immunity to, and available vaccines
Seasonal or (common) flu
What are the two primary functions of Influenza Hemagglutinin?
To identify vertebrate cells by binding to host cell receptors. Allowing the entry of the viral genome into the target cells.
the protein against which the host directs antibodies that can neutralize the virus
influenza hemagglutinin
How many HA subtypes are there?
18
Which HA subtypes are found in human influenza?
H1-3
HA subtype that attacks proteins in the digestive system of birds.
H5