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: minutes

Problem 1a

Textbook Question

How do we know that malignant tumors arise from a single cell that contains mutations?

Verified step by step guidance

Understand the concept of clonal origin of cancer: Malignant tumors are believed to arise from a single cell that has undergone genetic mutations. This is known as the clonal origin of cancer, where all the cells in the tumor are descendants of this single mutated cell.

Review evidence from genetic markers: Scientists have observed that cells within a tumor often share the same genetic mutations or chromosomal abnormalities, such as translocations or specific mutations in oncogenes or tumor suppressor genes. This suggests a common origin.

Examine X-chromosome inactivation studies: In female mammals, one of the two X chromosomes is randomly inactivated in each cell. Studies have shown that all cells in a tumor have the same X chromosome inactivated, further supporting the idea that the tumor originated from a single cell.

Consider the role of mutations in cancer progression: Mutations in key genes, such as proto-oncogenes, tumor suppressor genes, and DNA repair genes, can lead to uncontrolled cell division and tumor formation. The accumulation of these mutations in a single cell can initiate the development of a malignant tumor.

Explore experimental evidence: Techniques such as DNA sequencing and karyotyping have been used to analyze the genetic makeup of tumor cells. These methods reveal shared mutations among tumor cells, providing direct evidence for their clonal origin.

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Key Concepts

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

Clonal Evolution of Cancer

The concept of clonal evolution suggests that cancer arises from a single cell that undergoes mutations, leading to a population of genetically similar cells, or clones. This process allows for the accumulation of mutations that confer growth advantages, ultimately resulting in malignant tumors. Understanding this concept is crucial for recognizing how cancer can progress and become more aggressive over time.

Cell Cycle Regulation

The cell cycle is a series of phases that a cell goes through to divide and replicate. Proper regulation of the cell cycle is essential for maintaining normal cellular function and preventing uncontrolled cell growth. Mutations in genes that regulate the cell cycle, such as tumor suppressor genes and oncogenes, can lead to the dysregulation of this process, contributing to the development of cancer.

DNA Damage and Repair Mechanisms

DNA damage can occur due to various factors, including environmental influences and replication errors. Cells have evolved complex repair mechanisms to fix DNA damage, but when these systems fail or are overwhelmed, mutations can accumulate. The relationship between DNA damage and cancer is significant, as persistent mutations can lead to the transformation of a normal cell into a malignant one, highlighting the importance of genomic integrity in cancer prevention.

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Related Practice

Multiple Choice

Which of the following statements about cancer is false?

Which of the following are enzymes are responsible for controlling the cell cycle?

How do we know that cancer cells contain defects in DNA repair?

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Textbook Question

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

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Textbook Question

A tumor is a growing mass of abnormal cells. What must happen for a benign tumor to become malignant?

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Textbook Question

A tumor is a growing mass of abnormal cells. Give an example from this chapter of a benign tumor that becomes a malignant tumor.

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Textbook Question

A tumor is a growing mass of abnormal cells. Describe the difference between a benign tumor and a malignant tumor.

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Textbook Question

For the retinal cancer retinoblastoma, the inheritance of one mutated copy of RB1 from one of the parents is often referred to as a mutation that produces a 'dominant predisposition to cancer.' This means that the first mutation does not produce cancer but makes it very likely that cancer will develop. Define the 'two-hit hypothesis' for retinoblastoma.

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