Viruses Flashcards
1
Q
Why are viruses considered non-living
A
- Do not process cellular organelles/structures
- Do not make ATP or proteins
- Cannot replicate without a host
2
Q
Structure of viruses
A
- Made up of a protein coat called a CAPSID surrounding either DNA or RNA
3
Q
Capsid
A
- The protein shell of a virus, enclosing its genetic material
- protects virus from attack by host cell enzymes
- determines what kind of cell the virus will attach to
- assists with transport
4
Q
Nucleic acid
A
In viruses:
- DNA or RNA but not both together
- May be linear or circular in shape
5
Q
Classification of viruses according to the type of nucleic acid present
A
- DNA viruses
- RNA viruses
6
Q
RNA viruses
A
- Mutate faster since the RNA has to get processed and turned into DNA
- Include: retroviruses (ie. HIV)
- NOTE: retroviruses are special since they contain RNA and an enzyme called REVERSE TRANSCRIPTASE
7
Q
Retrovirus Growth
A
- Reverse transcriptase copies viral RNA and converts it into DNA which is usable in the host cell
- Retroviral proteins are synthesized by the host cell and the virus buds from the host to spread
- RNA viruses mutate faster than DNA viruses and are therefore more difficult to treat
8
Q
Bacteriophage
A
- Viruses that attack bacteria
- Undergo two types of reproduction
9
Q
Lytic cycle (bacteriophage)
A
The virus lyses or destroys the host cell within about 30-35 minutes
10
Q
Lysogenic cycle (bacteriophage)
A
- The virus integrates its genetic info into the host DNA, therefore creating a “Temperate” virus (one that does not destroy its host immediately)
- Takes hours or days
11
Q
Viral Envelope
A
- Surrounds some viruses
- Its an outer membrane surrounding the capsid
12
Q
Vaccines
A
- Injection of small amounts of dead/weakened/altered strains of a virus into the bloodstream
- Body makes antibodies
- Often multiple shots are required
13
Q
Antiviral Drugs (2 types)
A
Block viral replication - stop reverse transcriptase
Protease Inhibitors - block viral ‘protease’ enzymes so that new viral particles cannot infect new cells
14
Q
Antibiotics
A
Antibiotics will not work against viruses, they are made to target living cells
15
Q
Viruses in biotechnology
A
- At the end of the lytic cycle, there are more copies of DNA of interest (ie. if you wanted to multiply the amount of DNA found at a crime scene)
- Genes can also be moved from one place to another using “Gene Therapy” where normal genes are inserted into stem cells within the bone marrow, by using “disarmed” vector viruses that contain the normal gene
