lungs and the respiratory system

• Why would cells be unable to respire at very high temperatures?

  High temperatures can denature enzymes involved in respiration.
• How does a person pay back their oxygen debt after exercise?

  By breathing deeply to restore oxygen levels.
• What are the reasons larger animals need a respiratory system?

  • Smaller surface area: volume ratio
  • Insufficient diffusion rate for oxygen supply
  • Higher activity levels requiring more oxygen
• What do very small animals use for gas exchange?

  Diffusion across their body surface.
• What is the role of the trachea in the respiratory system?

  The trachea is a tube that carries air to the lungs.
• What are bronchi?

  Bronchi are the two tubes that branch from the trachea.
• What are bronchioles?

  Bronchioles are smaller tubes that branch from the bronchi.
• What is an alveolus?

  An alveolus is a small air sac where gas exchange occurs.
• What is the function of the ribs in the respiratory system?

  The ribs protect the lungs and assist with breathing.
• What is the diaphragm's role in breathing?

  The diaphragm helps with the inhalation and exhalation process.
• What is the mechanism of breathing based on pressure differences?

  • Air moves from areas of higher pressure to lower pressure.
  • This principle governs both inhalation (inspiration) and exhalation (expiration).
• What type of respiration do 100 m sprinters primarily use?

  Anaerobic respiration.
• What causes a sprinter's muscles to respire anaerobically?

  High intensity and short duration of the sprint lead to insufficient oxygen.
• Why would it be a problem for long-distance runners if their muscles respired anaerobically for a considerable time?

  Anaerobic respiration leads to lactic acid buildup, causing fatigue.
• Why do sprinters breathe more rapidly and deeply after their race finishes?

  To repay oxygen debt and restore oxygen levels in the body.
• What is the purpose of soda lime in the respirometer experiment?

  To absorb carbon dioxide produced during respiration.
• What is the purpose of the glass beads in the control experiment?

  To serve as a baseline measurement without respiration.
• How do you calculate the average rate of movement of the liquid in the respirometer?

  By dividing the total distance moved by the time taken.
• Why might a student suggest putting the respirometers in a water bath at 30 °C?

  To maintain a constant temperature for accurate results.
• What are the main tasks accomplished by the food we eat as it moves through the gut?

  • Large molecules must be broken down to pass through the gut wall.
  • Insoluble molecules must be transported in solution.
• What is the endpoint of digestion?

  • All food molecules are absorbed.
  • Digestion must occur before absorption.
• What are the main types of molecules that are broken down during digestion?

  • Large carbohydrates (e.g., starch)
  • Fats
  • Proteins
• How can starch be identified in food tests?

  • Add iodine solution.
  • A blue-black color indicates the presence of starch.
• How can glucose be identified in food tests?

  • Add Benedict's solution.
  • The solution turns from blue to green, yellow, orange, and finally brick-red if glucose is present.
• How can protein be identified in food tests?

  • Add Biuret solution.
  • A copper II complex forms with peptide bonds.