Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
75 Cards in this Set
- Front
- Back
|
History of Viruses-- Who postulated that rabies was a "living thing" smaller than bacteria? |
Louis Pasteur |
|
|
History of Viruses-- Are viruses living or not living? |
not living |
|
|
History of Viruses-- Pasteur developed the 1st vaccine for rabies when? |
1884 |
|
|
History of Viruses-- Years of experimentation showed that viruses re acellular or multicellular? |
acellular (not a cell) |
|
|
History of Viruses-- They are obligate intracellular parasites. What does this mean? |
--Instruct that cells genetic and metabolic machinery to make/release new viruses |
|
|
History of viruses-- Do they have a defined shape, size, and chemical composition? |
yes |
|
|
History of viruses-- How is it best to describe them? |
as active or inactive |
|
|
How are viruses classified?
|
based on their structure, chemical composition, and similarities in genetic makeup |
|
|
What is the range of the size of a virus? |
from approximately 20 nm - 0.4 um (that should be that backward u) |
|
|
How many viruses can fit in bacteria cell? |
2,000
|
|
|
How many polio viruses can fit in a human cell? |
50 million |
|
|
Do viruses have specific shapes?
|
yes
|
|
|
Generalized virus structure-- What is the capsid? |
|
|
|
Generalized virus structure-- What does the capsid protect? |
genetic info |
|
|
Generalized virus structure-- What does the capsid house? |
the enzymes needed to infect the host cell |
|
|
Generalized virus structure-- What is the nucleocapsid? |
combo of genetic info and the capsid |
|
|
Generalized virus structure-- What are nucleic acids? |
--can be DNA or RNA |
|
|
Generalized virus structure-- What are enveloped viruses? |
modified piece of hosts cell membrane |
|
|
Generalized virus structure-- What is a naked virus? |
no envelope, just capsule |
|
|
Generalized virus structure-- What are spikes? |
both naked and envelope have glycoproteins, allow to attach to specific host cells |
|
|
5 step infection cycle-- What is this? |
the basic process for infecting everything |
|
|
What are the 5 steps? |
1) Attachment 2) Penetration and uncoating 3) Synthesis 4) Assembly 5) Release |
|
|
5 step infection cycle:
Step 1 Attachment-- Viruses bind ________ on the plasma membrane of the host. |
glycoproteins |
|
|
5 step infection cycle:
Step 1 Attachment-- What will the spike on the virus attach to? |
receptor on the host
|
|
|
5 step infection cycle:
Step 1 Attachment-- Specific receptors required; limits ________ of virus. |
range |
|
|
5 step infection cycle:
Step 1 Attachment-- Examples of attachment: |
--highly restricted such as measles in dogs --Hepatitis B can only attach to liver cells --Sometimes moderately restrictive such as polio infecting liver and nerve cells, can infect apes as well --low restrictions such as rabies |
|
|
5 step infection cycle:
Step 2 Penetration and uncoating-- How do enveloped viruses enter? |
through fusion or endocytosis |
|
|
5 step infection cycle:
Step 2 Penetration and uncoating-- How do naked viruses enter? |
only through endocytosis
|
|
|
5 step infection cycle:
Step 2 Penetration and uncoating-- What is uncoating? |
Viral nucleic acids are released into the cytoplasm of the host cell |
|
|
5 step infection cycle:
Step 3 Synthesis-- What is synthesis? |
Expression of viral genes to produce viral structural and catalytic genes |
|
|
5 step infection cycle:
Step 3 Synthesis-- Synthesis of _______ copies of genome. |
multiple |
|
|
5 step infection cycle:
Step 3 Synthesis-- What are the 3 types of replication strategies? |
--3B. RNA viruses --3C. Reverse transcribing viruses |
|
|
5 step infection cycle: Step 3 Synthesis: DNA viruses-- Where does replication usually happen? |
in the nucleus |
|
|
5 step infection cycle: Step 3 Synthesis:
Makes its own DNA polymerase. What does DNA polymerase do? |
Allows the virus to make new viruses even when the host cell is not replicating. |
|
|
5 step infection cycle: Step 3 Synthesis:
DNA is transcribed to ______. |
mRNA |
|
|
5 step infection cycle: Step 3 Synthesis: DNA viruses-- mRNA is translated to what? |
proteins required to form the capsid and other structures |
|
|
5 step infection cycle: Step 3 Synthesis:
Example: Variola virus |
--causative agent of small pox --Class A bioterror agent --last naturally contracted case was in 1977 in Somalia --two years later the World Health Organization (WHO) declared it eradicated |
|
|
5 step infection cycle: Step 3 Synthesis:
Example: Herpes Simplex 1 and 2 |
--2 has more lesions and more frequent reoccurences |
|
|
5 step infection cycle: Step 3 Synthesis:
Example: Varicella-zoster (chicken pox) |
--death in about 20% of cases --can reactivate later in life as shingles |
|
|
5 step infection cycle: Step 3 Synthesis: RNA viruses-- How does replication happen? |
in the cytoplasm |
|
|
5 step infection cycle: Step 3 Synthesis: RNA viruses-- Makes its own replicase. What is replicase? |
enzyme used for replication in RNA viruses
|
|
|
5 step infection cycle: Step 3 Synthesis: RNA viruses-- It lacks proofreading abilities which leads to what? |
mutations in the vira (genome) |
|
|
5 step infection cycle: Step 3 Synthesis:
What is Antigenic Drift? |
small changes in the viral genome that decrease the hosts immune system from recognizing the virus; specifically memory cells |
|
|
5 step infection cycle: Step 3 Synthesis: RNA viruses-- What is Antigenic Shift? |
|
|
|
5 step infection cycle: Step 3 Synthesis: RNA viruses-- Example of both Antigenic Drift and Antigenic Shift? |
influenza
|
|
|
5 step infection cycle: Step 3 Synthesis: RNA viruses-- Example: hemorrhagic viruses |
--ebola --Marburg Class A Terror agent --picked up from fluids --death rate: 20-90% depending on strain --death in about 2 weeks |
|
|
5 step infection cycle: Step 3 Synthesis: Replication of Reverse-transcribing viruses-- Reverse-transcribing viruses encode what enzyme? |
reverse transcriptase
|
|
|
5 step infection cycle: Step 3 Synthesis: Replication of Reverse-transcribing viruses-- Retroviruses have what kind of genome? |
example: HIV |
|
|
5 step infection cycle: Step 3 Synthesis: Replication of Reverse-transcribing viruses-- Reverse transcriptase synthesizes a ________ ________ ________. |
single DNA strand |
|
|
5 step infection cycle: Step 3 Synthesis: Replication of Reverse-transcribing viruses-- Complementary strand is synthesized to make dsDNA. The dsDNA is integrated into the _____ _____ _____. |
host cell chromosome (called a provirus) |
|
|
5 step infection cycle: Step 3 Synthesis: Replication of Reverse-transcribing viruses-- Once the dsDNA enter the host chromosome, it can produce what? |
a productive infection or remain latent
|
|
|
5 step infection cycle: Step 3 Synthesis: Replication of Reverse-transcribing viruses-- Once the DNA copy is made, can it be eliminated from the cell? |
no |
|
|
5 step infection cycle: Step 4 Assembly-- Protein capsid forms and then what happens? |
the genome and enzymes are packaged within the capsid
|
|
|
5 step infection cycle: Step 4 Assembly-- Depending on the virus, assembly where does assembly happen? |
in the nucleus or cytoplasm of the cell |
|
|
5 step infection cycle: Step 5 Release-- What is budding? |
--how most enveloped viruses are release --this is how a virus picks up an envelope |
|
|
5 step infection cycle: Step 5 Release-- How are naked viruses released? |
when the host cell dies, often by apoptosis (programmed cell death) initiated by virus or host
|
|
|
5 step infection cycle Step 5 Release: Lytic cycle vs Lysogeny-- What is a bacteriophage? |
virus that infects bacteria |
|
|
5 step infection cycle Step 5 Release: Lytic cycle vs Lysogeny-- What is lytic? |
undergo replication and/or release immediately |
|
|
5 step infection cycle Step 5 Release: Lytic cycle vs Lysogeny-- What is lysogeny? |
when viral genome enters the bacteria remains inactive and forms a prophage |
|
|
5 step infection cycle Step 5 Release: Lytic cycle vs Lysogeny-- What is the importance of both? |
the viral genome can give bacteria permanent traits that make it more pathogenic to us |
|
|
What is acute? |
--rapid onset --short duration |
|
|
Acute and Persistent Infections-- What is persistent? |
--continue for years or lifetime --may or may not slow symptoms |
|
|
Acute and Persistent Infections-- Can some infections exhibit both acute and persistent? |
example: HIV |
|
|
Acute and Persistent Infections-- Persistent infections can be _____ or _____. |
chronic, latent |
|
|
Acute and Persistent Infections-- What is a chronic infection? |
continuous production of low levels or virus particles |
|
|
Acute and Persistent Infections-- What is a latent infection? |
example: Herpes |
|
|
Acute and Persistent Infections-- What are prions? |
proteinaceous infectious agents |
|
|
Acute and Persistent Infections-- What are prions composed of? |
--only protein --no nucleic acids |
|
|
Acute and Persistent Infections-- What are prions linked to? |
--slow, fatal human and non-human animal diseases --review Table 13.6 (page 356) Prion Diseases |
|
|
Acute and Persistent Infections-- Prions are usually transmittable only _____ _____. |
within species |
|
|
Acute and Persistent Infections-- Where do prion proteins accumulate? |
in neural tissue |
|
|
Acute and Persistent Infections-- What happens to neurons in prion diseases? |
they die |
|
|
Acute and Persistent Infections-- What happens to tissues in prion diseases? |
they develop holes |
|
|
Acute and Persistent Infections-- What happens to brain function in prion diseases? |
it deteriorates |
|
|
Acute and Persistent Infections-- Table 13.6 (page 356) Prion Diseases |
Disease --host Scrapie --sheep and goats Bovine spongiform encephalopathy (mad cow disease) --cattle Chronic wasting disease --deer and elk Transmissible mink encephalopathy --ranched mink Exotic ungulate encephalopathy --antelope in South Africa Feline spongiform encephalopathy --cats Kuru --humans (caused by cannibalism) Variant Creutzfeldt-Jakob disease --humans (caused by consumption of prion-contaminated beef) Creutzfeldt-Jakob disease --humans (inherited) Gerstmann-Straussler-Scheinker syndrome --humans (inherited) Fatal familial insomnia --humans (inherited) |
