Viruses - T1 S2 Flashcards
What killed mor people in the US than WWI, WWII, the Korean War, and the Vietnam War combined?
the flu pandemic of 1918
Viruses are (smaller and simpler / larger and more complex) than cells.
smaller and simpler
What two things do all viruses have?
genetic info (DNA/RNA) and protein coat (capsid), some may have an envelope
the site where a virus exists in nature
reservoir
(T/F) Virtually all species of animals, fungi, plants, protists, and bacteria get viral infections.
True
(T/F) A virus can only enter a cell that has a specific receptor on its surface.
True
Are viruses alive?
no
Are viruses a part of the taxonomic hierarchy?
no,
grouped by chemical similarities instead
List the 5 stages viral replication occurs in.
attachment, penetration, synthesis, assembly, release
stage of viral replication: virus binds cell surface receptor
attachment
stage of viral replication: viral nucleic acid is released inside host cell
penetration
stage of viral replication: host cell manufactures viral nucleic acids and proteins
synthesis
stage of viral replication: new viruses are assembled from newly synthesized coat proteins, enzymes, and nucleic acids
assembly
stage of viral replication: new viruses leave the host cell
release
virus enters cell, immediately replicates and lyses the host
lytic infection
What is “phage therapy” used for?
bacterial infections
targeted to specific bacteria
genetic material of a virus is replicated along with the host cell’s chromosome, host isn’t immediately destroyed
lysogenic infection (can switch to lytic pathway)
the time between exposure to disease agent, and disease signs and/or symptoms
incubation period
virus causing dead and damaged cells in the airway cause respiratory symptoms including coughing and sore throat, fever and body aches caused by cytokines released by the immune system
influenza virus
causes flu
more cases of disease than expected
epidemic
a widespread, worldwide epidemic
pandemic
type of infection that does not produce disease symptoms, viral genetic information is inside the cell
latent infection
virus causing cold sores on lips; stressed cells release viruses that infect other cells, cold sores are localized death of these cells
herpes simplex virus type I
virus that uses reverse transcriptase
retrovirus
retrovirus with RNA genome that infects helper T cells (loss of these cells leads to AIDS)
HIV
virus causing cervical cancer by signaling host cell to divide continuously
human papillomavirus
What does HIV stand for?
Human Immunodeficiency Virus
What does AIDS stand for?
Acquired Immunodeficiency Syndrome
HIV leads to AIDS which leads to…
opportunistic infections
first virus ever discovered
tobacco mosaic virus
How are most viruses in plants spread?
by plant-eating insects, through plasmodesmata
What can we use in plants to fight off infections?
posttranscriptional gene silencing
What help fight viral infections?
drugs and vaccines
some of these interfere with enzymes or other proteins that are unique to viruses
antiviral drugs
What aspect of viruses complicates our ability to fight them off with?
genetic variability
(T/F) Few medicines inhibit viruses without killing the infected host cells.
True
What does vaccination do?
teaches immune system to recognize virus
In the process of making some vaccines, what is used to produce viruses?
fertilized chicken eggs
a viral disease that causes acute inflammation of the brain in humans and other warm-blooded animals
rabies
What is the incubation period of rabies?
typically 1-3 months
How is rabies spread?
animal bites
mosquito-transmitted virus (RNA) associated with microcephaly, causing learning disabilities, impaired motor functions, difficulty with movement and balance, and speech delays
Zika virus
an infectious RNA molecule; naked RNA, doesn’t encode proteins, interferes with ability to produce proteins
viroid
an infectious protein; abnormal form causes brain cells to die, cause of “mad cow disease” and Kuru
prion
virus that may be the ancestor of HIV
SIV ( simian immunodeficiency virus)
What was SIVsm identified as the source of?
HIV-2
normal cellular protein, multiple shapes; if one is abnormal it can cause disease, contact with abnormal forms causes normal form to switch
PrP
