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9. (a) Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology - Question 9 - 2019 - Paper 1
Question 9
9. (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:9. (a) Clostridium tetani is a bacterium that can be found in soil - Edexcel - GCSE Biology - Question 9 - 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 after vaccination because the vaccine introduces inactivated toxins that stimulate the immune system. This process leads to the production of antibodies. When Clostridium tetani bacteria enter through a cut, the immune system recognizes the bacteria and rapidly produces the necessary antibodies to neutralize the toxins before they can cause illness.
Step 2
Explain how these bacteria have become resistant to Colistin.
Answer
Bacteria can become resistant to Colistin through various mechanisms, including mutations that modify the target site of the antibiotic or through the acquisition of resistance genes via horizontal gene transfer. This means they might alter their cell membrane or enzymatically degrade the antibiotic, thereby rendering it ineffective.
Step 3
Explain how information from Figure 15 provides evidence for human evolution.
Answer
Figure 15 provides evidence for human evolution by showcasing the chronological order of stone tools in different rock layers. The presence of more advanced tools in higher layers suggests a progression in human cognitive and motor skills over time. Additionally, the transition from simple to more complex tools indicates the evolution of techniques and technology among early humans, which is indicative of developmental milestones in human evolution.