Chapter 33 Pt. 1 (overview of viruses)

Question 1

What are some characteristics of Viruses cells that are different than eukaryotic cells?

Answer 1

• no metabolic activity.
• can only replicate if injected within a cell.
• On average, smallest cell type of all. (approx: 50-100 nm).
• No plasma membranes.
• Contain different types of DNA or RNA and can be single/ double stranded.

Question 2

Are viruses considered true cells, or in other words living?

Answer 2

• they embody roughly 50% of the biological requirements to be considered living, and for that reason it depends of what biologist you ask this question to.

Question 3

What are the means in which viruses can be diverse of one anther?

Answer 3

• Morphological ( shape)
• Size
• different outer coating ( enveloped vs. nonenveloped)
• Genomes - some use double stranded DNA some use single stranded DNA, wide variety of variations. Some use RNA and whole bunch of variations.
  Life cycle preference: the outcome of the life cycle results in the production of new viruses.

Question 4

What is the difference between enveloped vs. nonenveloped outer coating.

Answer 4

• Both contain capsids, but the non-enveloped only contains capsids (shell containing proteins).
• While, the enveloped ones contain a capsid surrounded by a phospholipid bilayer that they bonked from a host cell.

Question 5

What is a capsid?

Answer 5

An outer shell containing proteins.

Question 6

What are viruses genomes composed of?

Answer 6

DNA, RNA, Single stranded, or doubled stranded.
- The point here is that viruses genome can be a lot of different things, thus representing the diversity factor of their genome.

Question 7

What is the difference between Lytic Cycle &Replicative growth & Lysogeny?

Answer 7

• :Replicative growth:
  1.) virus infects a host cell
  2.) inside the host cell the viral genome is converted to mRNA, which is translated to proteins
  3.) The viral genome is then reproduced.
  4.) The proteins in the new genome assemble into new virions, and those leave the host.
  ————————————————————————
  Viral Latency: seen in bacterial phages (their version of replicative growth)
  Lysogeny:
  1.) Viruses injects its own genome and it is incorporated into the host cell’s chromosomes
  2.) The viruses or viral genome is then replicated during the cell cycle.
  3.) Allows for propagation of the viral genome without production of new virions.
  4.) eventually the infected cell will get activated viral mRNAs and proteins will be made and new virions will be assembled and it will switch to a lytic life cycle.

Question 8

What is the the Baltimore Classification System?

Answer 8

• A system for categorizing viruses into classes into classes based on the nature of the genome, and what they have to do to utilize that system.

Question 9

What is a virion?

Answer 9

individual viral particle.

Question 10

What is a bacterial phage?

Answer 10

Viruses that infects bacteria and bacteria only.

Question 11

What does it mean to be obligate intracellular?

Answer 11

It means it must occur within the cell which is the way viruses must function

Question 12

What is a Bacteria-Phage?

Answer 12

Specifically injects its DNA into other living cells (other bacteria), but it cannot do so in eukaryotic cells.

Question 13

T/F more than one life cycle can be seen in a virus?

Answer 13

T

Question 14

What is the product of replicative growth?

Answer 14

outcome of lifecycle results in new viruses.