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3. (a) Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology - Question 3 - 2019 - Paper 1
Question 3
3. (a) Clostridium tetani is a bacterium that can be found in soil. It causes the infection tetanus. Children are vaccinated against tetanus. Explain why these child... show full transcript
Worked Solution & Example Answer:3. (a) Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology - Question 3 - 2019 - Paper 1
Step 1
Explain why these children do not get tetanus if the bacteria enter their body through a cut in the skin.
Answer
Children do not get tetanus despite the bacteria entering through cuts due to vaccination. The tetanus vaccine introduces inactivated toxins from Clostridium tetani, which stimulates the immune system to produce antibodies without causing the disease. When exposed to the actual bacteria, these children are already equipped with the antibodies. As a result, their immune system can effectively neutralize the toxins and prevent the infection, hence providing immunity against tetanus.
Step 2
Explain how these bacteria have become resistant to Colistin.
Answer
Bacteria can become resistant to Colistin through several mechanisms. Firstly, mutations in the bacterial genes may lead to changes in the target sites of the antibiotic, decreasing its effectiveness. Additionally, bacteria may acquire resistance genes from other bacteria through horizontal gene transfer, expressing proteins that modify the antibiotic's action. Moreover, alterations in the outer membrane of gram-negative bacteria may prevent Colistin from entering the cell, further contributing to resistance. This adaptive response ultimately allows bacteria to survive in the presence of Colistin.