Lecture 5 - Viruses

Question 1

True or false - Viruses are the simplest forms of life

Answer 1

True

Question 2

True of false - viruses are neither prokaryotes no eukaryotes

Answer 2

True

Question 3

True or false - Viruses can be seen under a microscope

Answer 3

False -They are extremely small, smaller than bacteria. They can only be seen using and ELECTRON microscope

Question 4

T or F - live inside living cells, and cannot carry out any metabolic reactions on their own

Answer 4

True

Question 5

Difference between enveloped, and envelope-free viruses

Answer 5

Enveloped viruses are more susceptible to environmental factours, where as envelope-free viruses are more resistant and survive well in outside world.

Question 6

What is a capsid?

Answer 6

A protein coat of a virus, comprised of protein subunits called capsomeres.

Question 7

What shapes can capsids be?

Answer 7

Polyhedral, rod or complex

Question 8

What is the envelope of a virus?

Answer 8

It is the outer surface (not all viruses have them).

Question 9

Name the two types of viruses based on the genetic material they contain

Answer 9

DNA and RNA viruses

Question 10

Viruses show host specificity. What is the initial basis of this?

Answer 10

The ability of the virus particle to attach to the host cell.

Question 11

After fusion of viral and host membranes the virus particle is carried into where?

Answer 11

The cytoplasm

Question 12

When the envelope and/or capsid are shed (once in the cytoplasm), what is released?

Answer 12

The viral nucleic acid

Question 13

What are the 7 stages in infection of the host cell and viral replication?

Answer 13

Adsorption, penetration, un-coating, synthesis (replication), assembly, synthesised capsomeres as assembled in host cell, release.