Viruses

Question 1

What is a virus?

Answer 1

A virus is a small obligate parasite. This means that they cannot survive or reproduce without a host species.

Question 2

What are 4 ways a virus can spread in humans?

Answer 2

Coughing
Sneezing
Faeces to food
Mixing of blood and bodily fluids

Question 3

What are three ways viruses can spread in plants?

Answer 3

Insects
Seeds
Bulbs and Cuttings

Question 4

What are the 4 structures of a virus?

Answer 4

Helical
Polyhedral
Spherical
Complex

Question 5

What is a virus composed of?

Answer 5

DNA or RNA surrounded by a capsid (protein coat).

Sometimes a capsid is also surround by an envelope (Spikey coat).

Question 6

What are the 7 stages of viral replication?

Answer 6

1. Approach - Chooses host cell
2. Attach - Attaches to host cell
3. Penetrate - Injects DNA into the host
4. DNA Replication - viral DNA is replicated
5. Protein Synthesis - viral DNA allows protein synthesis to occur and new viral molecules are formed.
6. Assembly - viral DNA becomes enclosed in a protein coat.
7. Release - host cell membrane bursts, releasing many copies of the virus.

Question 7

During viral replication what does the virus use as energy.

Answer 7

The hosts source of ATP is the viruses source of energy.

Question 8

What is a retrovirus?

Answer 8

A retrovirus contains RNA. It uses the enzyme called reverse transcriptase to convert the viral RNA into viral DNA, so that the DNA can undergo replication.

Question 9

What is an example of a retrovirus?

Answer 9

HIV