Cell division

• What are chromosomes made up of?

  DNA and proteins
• Chromosomes contain genes which provide instructions for protein synthesis
• A gene is a section of DNA that codes for a protein.
• How many chromosomes are found in the nucleus of human body cells?

  46
• The nucleus of gametes contains 23 chromosomes.
• Chromosomes in body cells are arranged in pairs.
• What are the three main stages of the cell cycle?

  1️⃣ Replication of DNA and synthesis of organelles

  2️⃣ Mitosis

  3️⃣ Division of cell
• Why is mitosis important for growth and repair?

  Produces identical cells
• The first stage of the cell cycle is the longest and involves the replication of DNA
• What happens to chromosomes during the second stage of the cell cycle?

  Pulled to opposite poles
• In the third stage of the cell cycle, the cytoplasm and cell membrane divide to produce two identical daughter cells.
• What is a stem cell?

  An unspecialized cell
• Embryonic stem cells can replicate themselves and differentiate into other types of cells
• Match the stem cell type with its location:

  Embryonic stem cells ↔️ Embryos

  Adult stem cells ↔️ Bone marrow

  Meristem stem cells ↔️ Plant meristems
• What ability do meristem stem cells retain throughout a plant's lifespan?

  Differentiate into any plant cell
• Therapeutic cloning produces an embryo with the same genetic makeup as the patient.
• What is one advantage of cloning plants using meristem stem cells?

  Prevents extinction
• Many embryonic stem cells are sourced from aborted embryos
• What could happen if donor stem cells do not have a similar genetic makeup to the patient?

  Immune response triggered