Viruses

3. Viruses cause the symptoms of disease through the _____ of the host cell
9. Made up of simple repeating protein units known as capsomeres
10. New viral material that has been synthesised leaves the host cell through __________
14. Formed through the condensation reaction of nucleotides
16. Viruses that infect bacteria
20. A type of virus
21. Used as a template for new viral proteins and to synthesis new viral RNA genome.
22. ________ proteins prevents viral mRNA from being produced, and therefore stops the virus from becoming lytic

1. Spherical bodies in the cytoplasm of cells that contain digestive enzymes
2. Such as x-rays and ionising radiation increases the rate of mutation
4. Occur when viruses reproduce, therefore allowing them to evolve
5. The _____ envelope covers the genetic material and protein coat
6. An enzyme involved in the synthesis of new viral DNA
7. The presence of receptors on the virus means that they only bind to _______ host cells
8. When new virus particles start to invade other cells, the virus is said to be ________
11. The route of infection where viruses are non-virulent
12. A type of virus whose viral DNA is incorporated into the host cells DNA
13. Most scientists class viruses as 'obligate intracellular _________'
15. A substance that speeds up a reaction without being changed itself
17. Allows the virus to attach to a host cell
18. 'Cell suicide' - destruction of the contents of the cell
19. Directs the synthesis of a special enzyme called reverse transcriptase