Respiration and Gas Exchange

• What is the process of respiration primarily responsible for in living organisms?

  Releasing energy (ATP)
• What does ATP provide for cells?

  Energy
• What are the differences between aerobic and anaerobic respiration?

  • Aerobic respiration: Takes place with oxygen
  • Anaerobic respiration: Takes place without oxygen
• What is the word equation for aerobic respiration?

  Oxygen + glucose -> carbon dioxide + water
• What is the balanced chemical symbol equation for aerobic respiration?

  $6O_2 +$$C_6H_{12}O_6 -> 6CO_2 +$$6H_2O$
• What is the word equation for anaerobic respiration in animals?

  Glucose -> lactic acid (+ATP made)
• What is the word equation for anaerobic respiration in plants?

  Glucose -> ethanol + carbon dioxide (+ATP made)
• What are the steps to demonstrate the evolution of carbon dioxide and heat from respiring seeds?


  • Heat experiment:

  1. Set up flasks with germinating and dead seeds.

  2. Plug tops with cotton wool and hold thermometer.

  3. Invert flasks and record initial temperature.

  4. After 4 days, record final temperature.

  • Carbon dioxide experiment:

  1. Measure 10cm³ of lime water into boiling tubes.

  2. Add soaked seeds to one tube, boiled seeds to another, and leave one empty.

  3. Seal tubes and observe after 3 hours.

  
• What is the role of diffusion in gas exchange?

  Oxygen diffuses from alveoli into blood, and carbon dioxide diffuses from blood into alveoli.
• What are the main structures of the thorax involved in respiration?

  • Ribs: Protect internal organs
  • Intercostal muscles: Control rib movement
  • Diaphragm: Changes thorax volume
  • Trachea: Connects mouth/nose to lungs
  • Bronchi: Branching tubes for each lung
  • Bronchioles: Smaller tubes leading to alveoli
  • Alveoli: Air sacs for gas exchange
  • Pleural membranes: Reduce friction during breathing
• How do the intercostal muscles and diaphragm function in ventilation?

  • Inhalation:
  • Diaphragm contracts, moving down
  • Intercostal muscles contract, moving rib cage up and out
  • Volume of thorax increases, air pressure falls
  • Exhalation:
  • Diaphragm relaxes, moving up
  • Intercostal muscles relax, moving rib cage down and in
  • Volume of thorax decreases, air pressure rises
• What adaptations do alveoli have for gas exchange?

  • Large surface area
  • Thin walls (one cell thick)
  • Moist walls for gas dissolution
  • Permeable walls for gas passage
  • Good blood supply for oxygen transport
  • Large diffusion gradient maintained by breathing
• What are the biological consequences of smoking related to the lungs and circulatory system?

  • Emphysema
  • Bronchitis
  • Coronary heart disease
  • Lung cancer
  • Mouth cancer
  • Carbon monoxide poisoning
• How can breathing in humans be investigated?

  1. Sit for 5 minutes to find resting breathing rate.

  2. Perform vigorous exercise for 3 minutes.

  3. Record breathing rate immediately after exercise and until normal rate is reached.
• What are the excretory products of the lungs, kidneys, and skin?

  • Kidneys: Urea, water, mineral ions
  • Lungs: Carbon dioxide, water
  • Skin: Excess mineral ions (e.g., sodium), water