Cell differentiation & stem cells

• What is differentiation in cells?

  It is when a cell becomes specialised.
• Why is having specialised cells important?

  It allows organisms to work more effectively.
• What is the function of sperm cells?

  To deliver male DNA to the female egg.
• What features help sperm cells swim?

  Long tails and streamlined heads.
• Why do sperm cells contain lots of mitochondria?

  To provide them with energy.
• What is the role of enzymes in sperm cells?

  To digest through the egg cell membrane.
• What do specialised cells form in multicellular organisms?

  They form tissues.
• What are tissues?

  Groups of cells working together for a function.
• What do different tissues form?

  They form organs.
• What do different organs make up?

  They make up an organ system.
• What are stem cells?

  Undifferentiated cells that are not specialised.
• How do stem cells divide?

  By mitosis to become new cells.
• Where are embryonic stem cells found?

  In early human embryos.
• What can embryonic stem cells turn into?

  Any kind of cell at all.
• Why are stem cells important for organisms?

  For growth and development.
• Where are adult stem cells found?

  In certain places like bone marrow.
• What is the role of adult stem cells in animals?

  To replace damaged cells.
• What are meristems in plants?

  Tissues that contain plant stem cells.
• Where are meristems found in plants?

  In growing areas like root and shoot tips.
• What do meristems produce?

  Stem cells that can form any cell type.
• How long can meristems produce stem cells?

  For as long as the plant lives.
• What is diffusion?

  Movement from high to low concentration.
• What do cell membranes control?

  What enters and leaves cells.
• What can pass directly through the cell membrane?

  Only very small molecules.
• What must happen to particles too big to pass through the cell membrane?

  They must be transported in vesicles.
• What is active transport?

  Movement against a concentration gradient.
• What does active transport require?

  Energy from respiration.
• What substances are transported by active transport?

  Hormones around the body.