Viruses

Question 1

Viruses Characteristics

Answer 1

• Non-cellular structures.
• Made of protein coat (capsid) and one strand of DNA/RNA
• No Organelles
• Replicate, not reproduce
• Need a host cell to carry out chemical reactions

Question 2

Living?

Answer 2

• Contains DNA/RNA

- Can replicate (inside host cell)

Question 3

Dead?

Answer 3

• Non-cellular
• Cannot reproduce
• No organelles
• One type of Nucleic Acid (DNA)

Question 4

How does a virus replicate?

Answer 4

Only replicates inside host cell - use host cell machinery to make copies of itself

Question 5

Stages of Virus Replication?

Answer 5

1. Attachment- attaches to host cell surface
2. Entry- Forms a hole in host cell and inserts nucleic acid into host cell
3. Synthesis- DNA inactivated by viral enzymes
4. Assembly- New viruses are assembled inside host cell
5. Release- Host cell bursts and releases new viruses

Question 6

Bacteriophage

Answer 6

A virus that infects a bacteria

Question 7

RetroVirus

Answer 7

Contains RNA and an enzyme that converts RNA to DNA. DNA makes new copies of the virus RNA.

Question 8

Example of a RetroVirus

Answer 8

HIV - causes AIDS

Question 9

Benefits of Viruses

Answer 9

Genetic Engineering - Makes insulin

Bacteriophages- Control Bacterial infections and helps reduce infections

Question 10

Disadvantages of Viruses

Answer 10

Human diseases- Colds, rabies, AIDS
Animal Diseases- Rabies, cowpox
Plant Diseases- Plant mosaics

Question 11

What is not effective against viruses?

Answer 11

Antibiotics do NOT affect viruses

Question 12

What are viruses controlled by?

Answer 12

Bodies general defense system

Question 13

How can immunity be produced?

Answer 13

Produced artificially by vaccination

Question 14

Interferon

Answer 14

Produced by virus infected cells to protect healthy cells. Being produced artificially

Question 15

Antiviral Drugs

Answer 15

Interferon, helps treat colds and hepatitis B