Homework

• What is the aim of the experiment?

  To investigate the effect of sucrose solutions
• How is concentration measured in this experiment?

  In moles per dm³
• What does a 1.0 mol dm^-3 solution contain?

  One mole of substance per dm³
• What is the purpose of determining the concentration of cell sap?

  To understand the osmotic potential of potato cells
• What is the independent variable in the experiment?

  The concentration of sucrose solutions
• What concentrations of sucrose solutions are used?

  0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 mol/dm³
• What is the dependent variable in the experiment?

  The change in mass of potato cylinders
• What are the control variables in this experiment?

  Time and size of potato cylinders
• What is the method for conducting the experiment?

  1. Set up 6 boiling tubes with sucrose solutions.
  2. Prepare 6 potato cylinders of equal length.
  3. Dry and record the mass of each cylinder.
  4. Leave cylinders in solutions for 40 minutes.
  5. Remove, dry, and record the mass again.
  6. Repeat for multiple measurements to identify anomalies.
• What should be done to avoid cutting oneself with the cork borer?

  Place potato on a ceramic tile
• What safety precautions should be taken when using a scalpel?

  Care must be taken when using it
• What protective equipment should be worn when using chemical solutions?

  Wear eye protection
• What are the risks associated with the experiment?

  • Cutting oneself with the cork borer
  • Injury from the scalpel
  • Exposure to chemical solutions
• When do cells divide?

  When an organism grows or is damaged
• Why is it essential for new cells to contain genetic information?

  To ensure they are identical to the parent cell
• What are the stages of the cell cycle?

  • Cell growth
  • Synthesis of DNA
  • Cell division (mitosis)
• What is the first stage of the cell cycle?

  Cell growth
• What happens during the synthesis stage of the cell cycle?

  DNA is synthesized, producing exact copies
• What does each chromosome consist of?

  A single strand of DNA
• What is the purpose of mitosis?

  To produce two identical daughter cells
• What are the cells produced by mitosis called?

  Daughter cells
• How do daughter cells compare to the parent cell?

  They are identical to the parent cell
• How does the process of mitosis ensure genetic consistency?

  By producing identical daughter cells from DNA replication
• What do muscles need to contract?

  Energy
• Why do muscles need additional energy while exercising?

  To contract more efficiently during activity
• What happens to the breathing rate during exercise?

  It increases to bring in more oxygen
• What is the purpose of increasing heart rate during exercise?

  To supply muscles with extra oxygen
• What occurs if insufficient oxygen is available to the muscles?

  Muscles begin to respire anaerobically
• What is produced from glucose during anaerobic respiration?

  Lactic acid
• How does anaerobic respiration affect muscle contraction?

  Muscles contract less efficiently
• What happens to lactic acid levels during long periods of vigorous activity?

  Lactic acid levels build up
• What happens to glycogen reserves in muscles during vigorous activity?

  They become low as glucose is used
• Where is additional glucose transported from during exercise?

  From the liver
• What does the build-up of lactic acid produce?

  An oxygen debt
• What happens when body stores of glycogen become low?

  The person suffers from muscle fatigue
• What are the physiological changes during exercise that affect muscles?

  • Increased breathing rate and volume
  • Increased heart rate
  • Anaerobic respiration occurs if oxygen is insufficient
  • Lactic acid is produced instead of carbon dioxide
  • Muscle fatigue occurs as glycogen reserves deplete