Viruses

2. ________ proteins prevents viral mRNA from being produced, and therefore stops the virus from becoming lytic
3. Such as x-rays and ionising radiation increases the rate of mutation
5. New viral material that has been synthesised leaves the host cell through __________
7. Occur when viruses reproduce, therefore allowing them to evolve
8. Viruses cause the symptoms of disease through the _____ of the host cell
11. An enzyme involved in the synthesis of new viral DNA
14. Directs the synthesis of a special enzyme called reverse transcriptase
15. A type of virus
17. Allows the virus to attach to a host cell
18. The presence of receptors on the virus means that they only bind to _______ host cells
20. The _____ envelope covers the genetic material and protein coat

1. 'Cell suicide' - destruction of the contents of the cell
4. Formed through the condensation reaction of nucleotides
6. The smallest of all the microorganisms
8. The route of infection where viruses are non-virulent
9. Viruses that infect bacteria
10. Spherical bodies in the cytoplasm of cells that contain digestive enzymes
11. A type of virus whose genetic material whose viral DNA in incorporated into the host cells DNA
12. Most scientists class viruses as 'obligate intracellular _________'
13. A substance that speeds up a reaction without being changed itself
14. Used as a template for new viral proteins and to synthesis new viral RNA genome.
16. When new virus particles start to invade other cells, the virus is said to be ________
19. Made up of simple repeating protein units known as capsomeres