Chapter 2

• Cell division


  The process by which a parent cell divides into two or more daughter cells
• Reasons cells need to divide

  • To grow
  • To repair damage
  • To fight infection
• Mitosis


  1. Cell makes exact replicas of the parent cell

  2. Produces two daughter cells
• Stages of mitosis


  • Cell makes replica of itself
  • Chromosomes align at opposite ends of the cell
  • Nucleus divides
  • Cell membrane divides
• Each adult cell has 46 chromosomes, which are always the same
• Meiosis


  A type of cell division that produces non-identical daughter cells with half the number of chromosomes
• Meiosis only occurs in gametes (sperm and egg cells)
• At conception, there is only one cell, but by adulthood there are 37.2 trillion cells
• Cell differentiation

  • Cells develop into different cell types with specialized functions
  • Occurs mainly during embryonic development
  • Limited in adults
• Adult stem cells have a shorter life outside the body and fewer differentiation possibilities compared to embryonic stem cells
• Embryonic stem cell research is controversial due to ethical concerns and potential cancer risks
• Adult stem cells can be harvested from the patient's own body, reducing rejection risk
• Stem cell research aims to develop treatments for diseases like blindness, diabetes, paralysis, and Alzheimer's
• Plant cells can be cloned from cuttings, allowing for mass production of rare or desirable traits