Viruses

Question 1

What is a virus?

Answer 1

A virus is a particle made of genetic material encased in a protective protein coat
Infect a host cell and use its resources to replicate

Question 2

Are viruses alive?

Answer 2

Some debate
Viruses do not grow and develop
Do not carry out metabolic processes
Not made of cells and lack organelles
Can't replicate without a host
Viruses take control of a host and make it replicate the virus

Question 3

Explain the Structure or a virus

Answer 3

Genetic material surrounded in a protein coat (sometimes called a capsid)
Capsid surrounded by a layer of lipids
Some carry DNA and some carry RNA

Question 4

Explain the replication of a virus.

Answer 4

Attachment: virus binds to the receptor site on the host cell
Penetration: viruse either injects DNA or gets fully absorbed
Taking over: nucleic acid takes control of the host cell
Replication: genetic information codes for the production of proteins and nucleic acid
Assembly: the host cell packages the nucleic acid inside the capsid/protein coat
Release: eithe viruses burst out of the host cell and cause it to die (lyse) or get released in a vesicle from the cell membrane

Question 5

What are the 3 categories of RNA carrying viruses?

Answer 5

Positive-Strand: Viral RNA serves as mRNA can is translated directly to form proteins
Negative-Strand: viral RNA is the complement (matching pair) of mRNA and must be used to make RNA
Retroviruses: contain reverse transcriptase which codes for a DNA strand that becomes part of the host cell (lysogenic cycle)

Question 6

How do vaccines work?

Answer 6

Protect the body against disease by boosting the immune system
Vaccines mimic the virus without the side effects allowing the body to remember and develop antibodies to fight the disease