Cell Reproduction, Cancer, and Genetics

Apr 23, 2025

Lecture 32: Cell Reproduction and Cancer

Overview

  • Continuation of Chapter 10: Cell Reproduction.
  • Focus on cell cycle regulation and introduction to cancer.

Eukaryotic Cell Cycle and Regulation

  • Cell division is highly regulated with multiple checkpoints.
  • Cells divide when necessary and correctly.

Cancer

  • Defined as uncontrolled cell growth causing harm.
  • Caused by malfunctioning cell cycle control proteins.
  • Failure in proteins due to mutations in DNA.

Causes of Cancer

  • Mutations in proteins controlling cell cycle checkpoints.
  • Mutations arise from unrepaired DNA damage.

Key Terms

  • Proto-oncogene: Normal gene involved in the cell cycle, can become an oncogene when mutated.
  • Oncogene: Mutated gene that can lead to cancer.
  • Tumor Suppressor Genes/Proteins: Prevent mutations and cancer by repairing DNA damage.

p53 Tumor Suppressor Protein

  • Detects DNA damage and facilitates repair.
  • Can initiate apoptosis if damage is irreparable.
  • Mutations in p53 are common in cancers.

Chapter 11: Sexual Reproduction

Overview

  • Focus on sexual reproduction, a key aspect of multicellular eukaryotes.
  • Sexual reproduction leads to genetic diversity.

Importance of Sexual Reproduction

  • Creates diverse offspring, increasing survival chances.
  • Mixes genetic material from two parents.

Definitions

  • Diploid (2N): Cells with two sets of chromosomes.
  • Haploid (1N): Cells (like sperm and eggs) with one set of chromosomes.

Meiosis

  • Process creating haploid cells from diploid cells.
  • Involves special germ cells in reproductive organs.

The Meiosis Process

  • Meiosis I: Reduction division resulting in haploid cells with replicated DNA.

    • Prophase I: Chromosome tetrads form, allowing for crossover (exchange of genetic material).
    • Metaphase I: Tetrads align randomly, increasing variation.
    • Anaphase I: Homologous chromosomes are separated.
    • Telophase I & Cytokinesis: Cell divides into two haploid cells.

  • Meiosis II: Division similar to mitosis, separates sister chromatids.

    • Results in four unique haploid cells.

Genetic Variation

  • Crossover: Exchange of genetic material increases diversity.
  • Independent Assortment: Random orientation of homologous chromosomes.

Visual Aids

  • Diagrams comparing meiosis and mitosis.
  • Visual resources helpful for understanding cell division processes.

This concludes the lecture on Chapter 10 and Chapter 11, covering essential concepts in cell reproduction, cancer, and genetic diversity through sexual reproduction.

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