Viruses

Question 1

What is a virus consisting of?

Answer 1

They consist of s Nucleic acid core surrounded by a protein coat, called a capsid.

Question 2

Name two viruses.

Answer 2

Bacteriophages and Human immunodeficiency virus.

Question 3

What are all the organelles of a bacteriophage?

Answer 3

DNA
Head (capsid) of protein
‘Tail’ of protein
Contractile sheath (surrounding tubular core)
Baseplate of protein
Tail fibres (bind to bacterial cell surface).

Question 4

How do bacteriophages work?

Answer 4

They invade bacteria and the phage DNA codes for the production of new viral proteins (to make new coats). The phage DNA replicates to form many copies, which are then packaged in the new protein coats. Eventually the bacterial cells burst to release many new phages.

Question 5

What are all the organelles of the human immunodeficiency virus?

Answer 5

Membrane-associated protein shell.
RNA
Capsid protein (surrounding core)
Lipid bilayer.
Surface glycoprotein.
Reverse transcriptase.

Question 6

What is the group of viruses containing RNA called?

Answer 6

Retroviruses.

Question 7

What does reverse transcriptase do?

Answer 7

Uses the RNA as a template to produce single stranded DNA, double stranded DNA is then created with DNA polymerase activity.

Question 8

How does HIV destroy cells?

Answer 8

They contain reverse transcriptase which uses the RNA as a template to produce single stranded DNA, this creates double stranded DNA through polymerase activity. This viral DNA is integrated into the host DNA where it ensures that viral protein and new copies of RNA are made.

Question 9

What cells does HIV invade?

Answer 9

Invades the helper T-cells (a type of lymphocytes) and so may weaken the immune system, thereby causing AIDS, acquired immune deficiency syndrome.