Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

19. Cancer Genetics

Overview of Cancer

Genetics

19. Cancer Genetics

Overview of Cancer

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1:40 minutes

Problem 1b

Textbook Question

How do we know that cancer development requires more than one mutation?

Verified step by step guidance

Understand that cancer is a genetic disease caused by mutations in genes that regulate cell growth and division. These mutations can occur in proto-oncogenes, tumor suppressor genes, and DNA repair genes.

Recognize that cancer development typically requires multiple mutations because a single mutation is usually insufficient to disrupt the complex regulatory mechanisms of the cell cycle and DNA repair systems.

Consider the evidence from epidemiological studies, which show that the likelihood of developing cancer increases with age. This suggests that multiple mutations accumulate over time, leading to cancer.

Examine experimental evidence, such as studies on oncogenes and tumor suppressor genes, which demonstrate that introducing a single mutation into a normal cell does not typically result in cancer. Instead, multiple genetic changes are required to bypass the cell's regulatory checkpoints.

Review the concept of clonal evolution in cancer, where an initial mutation provides a growth advantage to a cell, and subsequent mutations further enhance its ability to proliferate uncontrollably, leading to tumor progression.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Multistep Carcinogenesis

Multistep carcinogenesis is the process by which cancer develops through a series of genetic mutations over time. This concept emphasizes that cancer is not caused by a single mutation but rather by the accumulation of multiple mutations in key genes that regulate cell growth and division, leading to uncontrolled cell proliferation.

Oncogenes and Tumor Suppressor Genes

Oncogenes and tumor suppressor genes are critical components in the regulation of the cell cycle. Oncogenes promote cell division and growth, while tumor suppressor genes inhibit these processes. Mutations in these genes can disrupt their normal functions, contributing to the development of cancer, which typically requires alterations in both types of genes.

DNA Damage and Repair Mechanisms

DNA damage can occur due to various factors, including environmental influences and replication errors. Cells have repair mechanisms to fix this damage, but if these mechanisms fail or are overwhelmed, mutations can accumulate. The relationship between DNA damage and cancer underscores the importance of multiple mutations in the progression of the disease, as it often takes several failures in repair processes to lead to cancerous growth.