Cell Diversity and Viruses Flashcards
T or F: Viruses are cells.
False
What are viruses?
Macromolecular packages that can function and reproduce only within living cells
What is a virion?
A virus outside of a host cell
Are virions animate or inanimate particles?
Virions exist as inanimate particles
What two things make up virions?
- A small amount of DNA or RNA
- A capsid
What is a capsid in a virion?
A protein capsule that packages genetic material
What are the 5 properties of cells that are shared with viruses?
- Complex and organized
- Controlled by a genetic program
- Able to carry out chemical reactions (sometimes)
- Able to reproduce (sometimes)
- Capable of evolving
What do viruses need to reproduce?
A host cell
When are viruses able to carry out chemical reactions?
Only when enzymes are present on the exterior of the virus
What is the Baltimore Classification System?
A popular system for classifying viruses
How does the Baltimore Classification System categorize viruses?
Based on their type of genome and method of replication
What is an example of a virus classified under the hepadnavirus family?
Hepatitis B
What is an example of a virus classified under the filovirus family?
Ebola virus
How does the filovirus family encode their genome?
In the form of single-stranded negative-sense RNA
What can viruses in the adenovirus family cause?
Respiratory illness or conjunctivitis
How do retroviruses infect host cells?
Insert a copy of their genome into the DNA of a host cell
Are retroviruses an RNA or DNA type virus?
RNA
What is an example of a retrovirus?
HIV
What type of cells do bacteriophages infect?
Infects and replicates within prokaryotes
What is CRISPR-Cas?
An immune-like system bacteria have evolved to possess as a way to battle continuous attacks from bacteriophages
How does CRISPR-Cas work?
Recognizes and remembers the attack from a virus, so it knows which enzymes to release to effectively and efficiently fight back
What is the main factor that determines what cell type a virus can infect?
The expression of specific surface proteins
What is the difference between narrow and wide host ranges?
- Narrow host range: viruses that have specific preferences in terms of which cells they infect
- Wide host range: viruses that infect a wide range of different cells
Do human cold and influenza viruses have narrow or wide host ranges?
Narrow
Does rabies have a narrow or wide host range?
Wide
What does a virus do once inside a host cell?
Hijacks cellular machinery to synthesize nucleic acids and proteins
What are the two main types of viral infections?
Lytic and non-lytic
What is the difference between lytic and non-lytic viruses?
- Lytic: produces virus particles that rupture/kill host cell
- Non-lytic: host cell can survive, but often with impaired function
What is a provirus?
Viral DNA inserted into the host genome
Are influenza and rabies lytic or non-lytic viruses?
Lytic
Are HIV and chicken pox lytic or non-lytic viruses
Non-lytic
What type of genome does the rabies virus have?
A single stranded RNA genome
How do RNA vaccines work?
Trick the body’s cells into producing an antigen from an RNA template, so when the actual virus attacks the body defends itself more effectively
What is an antigen?
A substance that causes the body to make an immune response against it
What is one strategy to make RNA vaccines more effective?
Incorporate the instructions for assembling a replicate within them
What will the replicas that result from self-amplifying RNA vaccine do?
Make copies of the RNA template for producing antigens
