Textbook Question
If a cell suffers damage to its DNA while in S phase, how can this damage be repaired before the cell enters mitosis?
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Ch. 19 - The Genetics of Cancer
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
Chapter 19, Problem 14
Of the two classes of genes associated with cancer, tumor-suppressor genes and oncogenes, mutations in which group can be considered gain-of-function mutations? In which group are the loss-of-function mutations? Explain.
Verified step by step guidance1
Understand the two classes of genes associated with cancer: tumor-suppressor genes and oncogenes. Tumor-suppressor genes normally act to inhibit cell division or promote apoptosis, preventing uncontrolled cell growth. Oncogenes, on the other hand, promote cell division and survival when activated.
Recall the definitions of gain-of-function and loss-of-function mutations. Gain-of-function mutations result in a gene product with enhanced or new activity, while loss-of-function mutations reduce or eliminate the normal activity of the gene product.
Analyze oncogenes: mutations in oncogenes typically lead to gain-of-function, meaning the mutated gene is overactive or constitutively active, driving excessive cell proliferation. This is because oncogenes are like the 'gas pedal' for cell growth.
Analyze tumor-suppressor genes: mutations here are usually loss-of-function, meaning the gene loses its ability to regulate or inhibit cell growth. This loss removes the 'brakes' on cell division, allowing uncontrolled growth.
Summarize that gain-of-function mutations are characteristic of oncogenes, while loss-of-function mutations are characteristic of tumor-suppressor genes, explaining their roles in cancer development.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Oncogenes and Gain-of-Function Mutations
Oncogenes are mutated forms of proto-oncogenes that promote cell growth and division. Gain-of-function mutations in these genes lead to their overactivation or constant activity, driving uncontrolled cell proliferation and contributing to cancer development.
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08:26
Functional Genomics
Tumor-Suppressor Genes and Loss-of-Function Mutations
Tumor-suppressor genes normally inhibit cell growth or promote apoptosis to prevent tumor formation. Loss-of-function mutations in these genes disable their protective roles, allowing cells to grow unchecked and increasing cancer risk.
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04:46Cancer Mutations
Difference Between Gain- and Loss-of-Function Mutations
Gain-of-function mutations enhance or create new gene activity, often dominant in oncogenes, while loss-of-function mutations reduce or eliminate gene activity, typically recessive in tumor-suppressor genes. Understanding this distinction is key to grasping how different gene classes contribute to cancer.
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10:48Mutations and Phenotypes
Related Practice
Textbook Question
Distinguish between oncogenes and proto-oncogenes. In what ways can proto-oncogenes be converted to oncogenes?
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Textbook Question
How do translocations such as the Philadelphia chromosome contribute to cancer?
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Textbook Question
How do normal cells protect themselves from accumulating mutations in genes that could lead to cancer? How do cancer cells differ from normal cells in these processes?
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Textbook Question
Radiotherapy (treatment with ionizing radiation) is one of the most effective current cancer treatments. It works by damaging DNA and other cellular components. In which ways could radiotherapy control or cure cancer, and why does radiotherapy often have significant side effects?
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