Year 9 Science · Unit 1 · Lesson 15
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Learning Goals
Because… chain
Fill in the missing effects. Each cause leads to the next step in the chain from UV exposure to melanoma spreading.
Overall outcome if melanoma is not detected early:
Real-world context
Marcus, a 45-year-old outdoor construction worker in Queensland, notices an irregular dark mole on his shoulder that has been growing over six months. He visits his GP, who biopsies the mole and diagnoses a stage II melanoma, a malignant tumour that has not yet metastasised. Marcus has fair skin, worked outdoors without sun protection for 20 years, and has no known family history of melanoma. His oncologist discusses treatment options including surgical excision, targeted therapy with a BRAF inhibitor, and immunotherapy.
(a) Identify the most likely carcinogen responsible for Marcus's melanoma and explain the mechanism by which it causes DNA damage.
(b) Explain why apoptosis failed to prevent Marcus's melanoma from developing, even though this process normally removes damaged cells before they can multiply.
(c) His oncologist mentions a BRAF inhibitor (like vemurafenib). Explain why this targeted therapy approach is preferable to general chemotherapy for a BRAF-mutated melanoma.
1. Explain why 1 in 2 Australians will be diagnosed with cancer by age 85, even though the body destroys approximately 10 billion abnormal cells every day.
2. Compare the roles of surgery and immunotherapy in treating cancer. For each treatment, describe what it does and one advantage it has over the other.
Wrap Up
In one sentence, what was the most important connection you made in this worksheet?