Cancer is generally caused due to activation of ………..to ………….and/or inactivation of ……….

Options

A. Oncogene, tumour suppressor gene, protooncogene
B. Tumour suppressor gene, oncogene, protooncogene
C. Oncogene, protooncogene, tumour suppressor gene
D. Protooncogene, oncogene, tumour suppressor gene

Answer

**Step-by-Step Solution:**

1. **Understanding Cancer**: Cancer is a disease characterized by uncontrolled cell growth. It is generally caused by genetic mutations that affect cell division and growth.

2. **Identifying Key Genes**: There are two main types of genes involved in cancer development:
- **Oncogenes**: These are mutated forms of proto-oncogenes that have the potential to cause cancer by promoting excessive cell division.
- **Tumor Suppressor Genes**: These genes normally function to inhibit cell division and promote apoptosis (programmed cell death). When these genes are inactivated, their protective effect is lost, leading to uncontrolled cell growth.

3. **Filling in the Blanks**: The question asks for the activation and inactivation processes related to cancer:
- The activation of **proto-oncogenes** to **oncogenes** leads to cancer.
- The inactivation of **tumor suppressor genes** also contributes to cancer development.

4. **Conclusion**: Therefore, the correct way to fill in the blanks is:
- Cancer is generally caused due to activation of **proto-oncogenes** to **oncogenes** and/or inactivation of **tumor suppressor genes**.

5. **Final Answer**: The correct option is **D**: proto-oncogene, oncogene, tumor suppressor gene.

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