#5 - Viruses

Question 1

What’s the major difference between viruses and bacteria?

Answer 1

Viruses are non-living.

Question 2

What are the 4 things viruses lack?

Answer 2

1. Cells
2. Cell membrane
3. Cytoplasm
4. Organelles

Question 3

True or False? Viruses can carry out respiration and other life processes.

Answer 3

False

Question 4

What’s a capsid? What does it contain?

Answer 4

A capsid is a protein shell that protects the virus and allows it to attach to host cells. It contains the virus’ DNA and RNA.

Question 5

What’s the primary characteristic viruses share with living things? How?

Answer 5

The ability to multiply. The virus cannot do this on it’s own, it relies on the metabolism of a host cell to replicate it’s DNA and RNA.

Question 6

What are the two types of viral reproduction? Describe them.

Answer 6

1. Lytic: Immediate infection and symptoms.
2. Lysogenic: Viral DNA becomes integrated into the host cell’s genome and is passed on through mitosis.

Question 7

Briefly describe the 5 stages of the lytic cycle.

Answer 7

1. Attachment: Virus attaches to a specific receptor site on the cell membrane of its host.
2. Entry: Virus injects nucleic acid into its host.
3. Replication: The viral DNA and RNA become replicated, and the host’s DNA starts to break down.
4. Assembly: New virus particles are assembled.
5. Lysis and Release: The host cell breaks open (lysis) and newly formed viruses are released to go on to infect more cells.

Question 8

Briefly describe the three stages of the lysogenic cycle.

Answer 8

1. Insertion of DNA into the host genome.
2. Cell division.
3. Release of vira DNA due to environmental signals.