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6. Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology Combined Science - Question 6 - 2019 - Paper 1
Question 6
6. Clostridium tetani is a bacterium that can be found in soil. It causes the infection tetanus. Children are vaccinated against tetanus. Explain why these children... show full transcript
Worked Solution & Example Answer:6. Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology Combined Science - Question 6 - 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 are immunized against Clostridium tetani through vaccination. The vaccine contains inactive or dead bacteria or antigens that stimulate the immune system. This prompts the formation of memory lymphocytes. When the actual bacteria enter the body, these memory cells quickly recognize them and lead to the production of antibodies, providing a secondary immune response that effectively eliminates the threat of tetanus infection.
Step 2
Explain how these bacteria have become resistant to Colistin.
Answer
Bacteria can develop resistance to Colistin through genetic mutations or acquiring resistant genes from other bacteria. These mutations may alter the target site of Colistin in the bacteria, rendering the antibiotic ineffective. Additionally, the overuse of antibiotics can increase selective pressure, allowing resistant strains to survive and multiply.
Step 3
Explain how information from Figure 8 provides evidence for human evolution.
Answer
The different layers of rock in Figure 8 indicate a chronological sequence of tool use by early humans. Tools found in deeper layers suggest that they are older compared to those found in upper layers. This pattern supports the idea of gradual evolution, showcasing the advancement in tool-making skills over time, which reflects the cognitive development of early human ancestors.