Organisation

• What is the primary function of muscle cells?

  They can contract to facilitate movement.
• Why do muscle cells contain many mitochondria?

  To provide energy needed for contraction.
• What is a tissue?

  A group of cells with similar structure.
• How is an organ defined?

  A group of tissues working together.
• What types of tissue does the stomach contain?

  Muscle tissue and glandular tissue.
• What are organ systems?

  Groups of organs working together.
• What are the three types of nutrients found in food?

  Starch, protein, and fats.
• Why must large food molecules be digested?

  To break them down into small molecules.
• What role do enzymes play in digestion?

  They break down large food molecules.
• What happens in the mouth during digestion?

  Food is chewed and starch begins digestion.
• What is the function of hydrochloric acid in the stomach?

  It helps enzymes digest proteins.
• What is the role of bile in digestion?

  It helps emulsify lipids for digestion.
• Where is bile produced and stored?

  Produced in the liver, stored in the gall bladder.
• How does bile affect lipid digestion?

  It increases the surface area of lipid droplets.
• What happens to enzymes at high temperatures?

  They can become denatured and inactive.
• What is the optimum pH for protease enzymes?

  It works best at an acidic pH.
• What is the purpose of the required practical on amylase?

  To investigate the effect of pH on amylase activity.
• What are the steps in the required practical for amylase?

  1. Prepare iodine solution in wells.
  2. Mix starch, amylase, and buffer in test tubes.
  3. Incubate at 30°C for 10 minutes.
  4. Combine solutions and start timing.
  5. Test for starch presence with iodine.
  6. Record time until iodine remains orange.
  7. Repeat with different pH buffers.
• What is the test for starch using iodine?

  If present, it turns blue-black.
• What does Benedict's solution test for?

  It tests for the presence of sugars.
• What color indicates a moderate amount of sugar in Benedict's test?

  Yellow color indicates moderate sugar.
• What is the function of villi in the small intestine?

  They increase the surface area for absorption.
• What is the length of the small intestine?

  Approximately 5 meters long.
• How do microvilli enhance absorption in the small intestine?

  They further increase the surface area.
• What type of circulation system do humans have?

  Humans have a double circulatory system.
• What is the role of the coronary arteries?

  To supply oxygen to heart muscle cells.
• What is the function of the pacemaker in the heart?

  It controls the natural resting heart rate.
• What is an artificial pacemaker?

  A device that corrects heart rate irregularities.
• What happens to the active site of an enzyme at extreme pH?

  It denatures and loses functionality.
• What is the effect of temperature on enzyme activity?

  Increased temperature raises enzyme activity until denaturation.
• How does the structure of the heart support its function?

  Thicker walls in the left ventricle pump blood efficiently.
• What is the role of the left atrium in the heart?

  It receives oxygenated blood from the lungs.
• What is the function of valves in the heart?

  To prevent backflow of blood.
• What happens during the contraction of the ventricles?

  Blood is forced out of the heart.
• What is the role of the vena cava?

  It brings deoxygenated blood from the body.
• How does oxygenated blood return to the heart?

  Through the pulmonary veins from the lungs.
• What is the main purpose of respiration in heart muscle cells?

  To provide energy for contraction.
• What happens if the pacemaker malfunctions?

  It may require an artificial pacemaker.
• What is the function of lipase?

  To digest lipid molecules into glycerol and fatty acids.
• What is the role of amylase in digestion?

  To break down starch into simple sugars.