Biology Unit 6 - Evolutionary Race 0.0 / 5 ? BiologyHealth, illness and diseaseA2/A-levelEdexcel Created by: lauraking20Created on: 11-06-17 14:17 Evolutionary race? Struggle between pathogens and their hosts to outdo each other 1 of 9 What is antigenic variation? How different strains of pathogen are developed 2 of 9 How does this happen in HIV? Has a high mutation rate in the genes that code for antigens - this changes the structure of the antigens and forms new strains 3 of 9 What does this mean for memory cells? They won't recognise the new strain of hIV - ineffective 4 of 9 What does HIV disrupt? Antigen presentation in infected cells 5 of 9 What does this mean? Prevent immune system cells from recognising and killing infected cells 6 of 9 Mycobacterium Tuberculosis evasion mechanisms? 1) Prevent lysosome fusing 2) Disrupts antigen presentation 7 of 9 How can it prevent lysosome fusing? Produce substances that prevent it fusing with vacuole - so bacteria arent broken down and can multiply undetected 8 of 9 What does it disrupting antigen presentation mean? Prevents immune system celles from recognising and killing the infected phagocytes 9 of 9
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