cell division

• What are chromosomes made up of?

  Chromosomes consist of DNA molecules combined with proteins.
• What is the function of genes within chromosomes?

  Genes provide the instructions for protein synthesis.
• How many chromosomes are found in the nucleus of human body cells?

  46
• How many chromosomes are found in the nucleus of gametes?

  23
• How are chromosomes arranged in the nucleus of a body cell?

  Chromosomes are arranged in pairs, forming 23 pairs of 46 chromosomes.
• What are the three main stages of the cell cycle?

  1. Replication of DNA and synthesis of organelles
  2. Mitosis
  3. Division of cell
• Why is mitosis important?

  Mitosis produces identical cells with the same genetic information and additional cells for growth and repair.
• Describe the first stage of the cell cycle.

  In the first stage, cells grow, increase in mass, replicate DNA, and synthesize more organelles.
• Describe the second stage of the cell cycle.

  In the second stage, each chromosome in a pair is pulled to opposite poles of the cell, and then the nucleus divides.
• Describe the third stage of the cell cycle.

  In the third stage, the cytoplasm and cell membrane divide, producing two identical daughter cells.
• What is a stem cell?

  A stem cell is an unspecialized cell capable of differentiating into other cell types and of self-renewal.
• What is the function of stem cells in embryos?

  Embryonic stem cells can replicate themselves and differentiate into many other types of cells, potentially treating conditions like paralysis and diabetes.
• What is the function of stem cells in adult bone marrow?

  Adult stem cells can differentiate into several cell types to replace dead or damaged tissues, such as forming different types of blood cells.
• What is the function of stem cells in plant meristems?

  Meristem stem cells can differentiate into any type of plant cell throughout their lifespan as needed by the plant.
• What is therapeutic cloning?

  Therapeutic cloning is a method where an embryo is produced with the same genetic makeup as the patient to create stem cells that won't be rejected by the immune system.
• What are the advantages of cloning plants using meristem stem cells?

  • Prevents rare plants from becoming extinct
  • Produces large numbers of plants with favorable characteristics
  • Produces identical plants for research
• What are the issues associated with the use of embryonic stem cells?

  • Ethical/religious objections to sourcing from aborted embryos
  • Slow, expensive, and difficult development of stem cell therapies
  • Risk of infections from adult stem cells infected with viruses
  • Immune response if donor stem cells do not match the patient’s genetic makeup