Chapters 10 & 11

Viruses and Cellular Defence Mechanisms

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1. exhibit living and non-living characteristics and can only reproduce within the living cells of another organism.

2. A virus consists of one type of acid surrounded by a coat of .

3. Once inside a host cell, the virus alters the cell’s metabolism to produce many identical copies of itself.

4. The two main mechanisms employed by the human body depend on the activities of blood cells.

5. Phagocytes engulf and destroy microbes by using lysosomes. This is a immune response.

6. recognise antigens on the surface of a microbe and produce . These possess receptors sites which bind to one particular type of rendering it harmless. This is a immune response.

7. do not make antibodies. They defend themselves against invasion by producing compounds such as , cyanide and .

8. Some plants can isolate an area of injury by secreting sticky .