Respiration

• What is respiration?

  It is a process by which energy is produced from the oxidation of food.
• What are the two types of respiration?

  Aerobic and anaerobic respiration.
• What is aerobic respiration?

  Aerobic respiration is the release of energy by the breakdown of glucose in the presence of oxygen.
• What happens to food molecules during aerobic respiration?

  Food molecules are oxidised, converting carbon atoms into carbon dioxide and hydrogen into water.
• What is the equation for aerobic respiration?

  glucose + oxygen -> carbon dioxide + water
• What role do mitochondria play in aerobic respiration?

  Mitochondria catalyse the process of aerobic respiration.
• Why is energy needed in the body?

  Energy is needed for processes such as synthesis of new protoplasm, protein synthesis, muscular contraction, and cell division.
• What happens to energy in animals during respiration?

  Some energy is released as heat to maintain body temperature.
• What is anaerobic respiration?

  It is the release of energy by the breakdown of glucose in the absence of oxygen.
• What is produced during anaerobic respiration in muscle cells?

  Lactic acid is produced.
• What is the word equation for anaerobic respiration in muscle cells?

  glucose -> lactic acid
• What happens during vigorous exercise regarding respiration?

  If maximum aerobic respiration cannot meet energy demand, muscle cells carry out anaerobic respiration.
• What is the consequence of lactic acid buildup in muscles?

  The buildup of lactic acid causes fatigue and aching pain in the muscles.
• What is oxygen debt?

  Oxygen debt is the accumulation of lactic acid in the muscles.
• How can oxygen debt be removed?

  By continuing a fast heart rate and deeper, faster breathing.
• What is the objective of the experiments to study respiration?

  To investigate if energy is released during respiration.
• How can heat release during respiration be determined?

  By recording the readings in thermometers of germinating seeds.
• What is the purpose of potassium hydroxide in respiration experiments?

  It absorbs carbon dioxide.
• What indicates the presence of carbon dioxide in limewater?

  A white precipitate is observed.
• What happens to limewater in flask B during respiration experiments?

  Limewater should not have a white precipitate as potassium hydroxide has removed carbon dioxide.
• How can carbon dioxide release during fermentation be determined?

  If white precipitate is observed, it indicates carbon dioxide is produced during anaerobic respiration by yeast.
• What is fermentation?

  Fermentation is the action of yeast on sugar solution to produce alcohol.
• What is gas exchange?

  Gas exchange refers to the exchange of gases between an organism and the environment.
• Why do humans require a constant supply of oxygen?

  For tissue respiration and to remove excess carbon dioxide, which is toxic.
• How does gas exchange occur in humans?

  Gas exchange occurs continuously between the human body and the atmosphere with the help of the respiratory system.
• What are the advantages of breathing through the nose?

  It traps dust and foreign particles, warms and moistens air, and detects harmful chemicals.
• What is the function of the trachea?

  The trachea is the passage from the back of the mouth to the lungs.
• What prevents the trachea and bronchi from collapsing?

  The presence of incomplete C-rings of cartilage.
• What do gland cells in the trachea do?

  Gland cells secrete mucus to trap dust particles and bacteria.
• What is the function of ciliated cells in the trachea?

  Ciliated cells sweep the dust-trapped mucus up the trachea.
• What are bronchi?

  Bronchi are two small tubes that branch out from the trachea and enter the lungs.
• What are alveoli?

  Alveoli are clusters of air sacs at the end of bronchioles.
• What characteristics of alveoli facilitate efficient gas exchange?

  Alveoli have a one cell thick epithelium, a dense blood capillary network, a thin layer of moisture, and a large number of alveoli.
• How does gas exchange occur in the lungs?

  Gas exchange occurs across the surface of the alveoli and blood capillaries through diffusion.
• What maintains the concentration gradient for gas exchange?

  A continuous flow of blood through the capillaries and continuous breathing.
• What happens to oxygen during gas exchange?

  Oxygen diffuses from the alveolar air into the blood.
• What happens to carbon dioxide during gas exchange?

  Carbon dioxide diffuses from the blood into the alveolar air.
• What happens to oxygen in red blood cells?

  Oxygen combines with haemoglobin to form oxyhaemoglobin.
• What happens to oxyhaemoglobin in tissues with low oxygen concentration?

  Oxyhaemoglobin dissociates easily to release oxygen.
• What is the function of the pulmonary vein?

  The pulmonary vein carries oxygenated blood from the alveoli to the left atrium of the heart.