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Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology Combined Science - Question 6 - 2019 - Paper 1
Question 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 d... show full transcript
Worked Solution & Example Answer: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 who are vaccinated against tetanus are immune to the effects of Clostridium tetani. The vaccination contains either a weakened, inactive form of the bacteria or its antigens, which stimulates the immune system without causing the disease. This process leads to the production of memory lymphocytes that remember the antigens. When these children are exposed to the bacteria through a cut, their immune system remembers the pathogens and mounts a rapid response by producing antibodies, effectively preventing the onset of tetanus.
Step 2
Explain how these bacteria have become resistant to Colistin.
Answer
Bacteria that are resistant to Colistin have often developed this resistance through several mechanisms. One method involves genetic mutations that alter target sites within the bacteria, reducing the drug's effectiveness. Another way is through the acquisition of resistance genes from other bacteria, often via horizontal gene transfer. This gene exchange can occur through plasmids, which are small DNA molecules, enabling them to withstand the action of Colistin and survive in its presence.
Step 3
Explain how information from Figure 8 provides evidence for human evolution.
Answer
The information presented in Figure 8 can show the progression of tool use and development over different layers of rock. Each tool, found in various strata, indicates the time period when it was used, reflecting the technological advancements of early humans. For instance, by analyzing the design and material of each tool in context with its respective layer, we can infer changes in behaviors, skills, and societal development. The presence of more advanced tools in younger layers suggests an evolutionary trend in human capabilities and adaptation over time.