Viruses

Question 1

What unit are viruses measured in?

Answer 1

nm (Nanometers)

Question 2

What coating do all viruses have surrounding the nucleic acid?

Answer 2

Protein coat (caspid)

Question 3

What nucleic acid is present in a Bacteriophage?

Answer 3

DNA (Deoxyribonucleic acid)

Question 4

How are new viruses formed in bacteriophages?

Answer 4

The DNA core replicates itself to make copies

Question 5

How are viruses released in a phage?

Answer 5

The bacterial cell is destroyed as it ruptures and many new viruses are released to continue the cycle

Question 6

What is HIV also known as?

Answer 6

The human immunodeficiency virus

Question 7

What core does a HIV virus have?

Answer 7

RNA core (ribonucleic acid)

Question 8

What additional layer does the HIV virus have that a bacteriophage does not?

Answer 8

A lipid bilayer containing glycoprotein

Question 9

Which enzyme is present in a HIV virus and what is its function?

Answer 9

Enzyme reverse transcriptase
-It catalyses the synthesis of DNA from RNA, to which the DNA then makes new viruses

Question 10

Why are HIV viruses known as retroviruses?

Answer 10

The viral RNA is used as a template to make DNA. This is the reverse of the normal transcription process, where DNA is used to make mRNA as a part of protein synthesis.

Question 11

Name the components that make up a Bacteriophage

Answer 11

-Base plate
-Tail fibres
-Contractile sheath (protein)
-DNA
-Caspid protein coat/ ‘head’

Question 12

Name the components that make up a HIV virus

Answer 12

-RNA
-Protein
-Phospholipid bilayer
-Glycoprotein
-Reverse transcriptase enzyme
-Caspid protein coat/ ‘head’

Question 13

What does the HIV virus invade in humans?

Answer 13

Lymphocyte called helper T-cells.
Helper T-cells are very important when protecting against disease.

Question 14

Name 3 similarities bacteriophages and HIV have

Answer 14

-very small
-non-cellular
-both contain genetic material within a protein coat

Question 15

Name any 3 differences between bacteriophages and HIV

Answer 15

-They have different shapes and phages have tail fibres attached to a base plate. The tail fibres are important in attaching the virus to bacterial cells.
-in HIV the protein coat/head is within a phospholipid bilayer.
-glycoproteins present in HIV but not in phages.
-bacteriophages normally contain DNA while HIV contains RNA.
HIV contains reverse transcriptase, (usually none in phages)