gas exchange

• What is the relationship between an organism's size and its surface area to volume ratio?

  Larger organisms have a lower ratio
• Why do single-celled organisms like amoeba not need special adaptations for gas exchange?

  They have a large surface area compared to volume
• What adaptations do larger organisms require for gas exchange?

  Mass transport systems for efficient exchange
• What are some key adaptations for gas exchange in different organisms?

  • Villi and microvilli in small intestines
  • Alveoli and bronchioles in mammals
  • Spiracles and tracheae in terrestrial insects
  • Gill filaments and lamellae in fish
  • Stomata in plants
• What is the definition of ventilation?

  Movement of air in and out of lungs
• How does gas exchange differ from respiration?

  Gas exchange is diffusion; respiration is chemical
• What are the key structures of the human gas exchange system?

  Alveoli, bronchioles, bronchi, trachea, lungs
• What role do the diaphragm and intercostal muscles play in ventilation?

  They control ribcage movement for breathing
• What is meant by antagonistic muscles in the context of ventilation?

  One muscle contracts while the other relaxes
• What happens to the diaphragm during inhalation?

  It contracts and moves downwards
• How does the volume of the thorax change during inhalation?

  The volume increases, causing pressure to drop
• What is the pulmonary ventilation calculation?

  Tidal volume times ventilation rate
• How many alveoli are there approximately in each lung?

  About 300 million
• Why do alveoli have thin epithelium cells?

  To minimize diffusion distance for gases
• What is the function of the tracheal system in terrestrial insects?

  It facilitates ventilation and gas exchange
• What are spiracles in insects?

  Valves for gas exchange openings
• How do insects ventilate their tracheal system?

  By contracting abdominal muscles
• What is the counter current flow mechanism in fish gills?

  Water flows opposite to blood in capillaries
• What is the primary gas exchange surface in fish?

  Gills
• What adaptations do fish gills have for gas exchange?

  Large surface area and short diffusion distance
• How do stomata help plants in gas exchange?

  They allow gases to diffuse in and out
• When do stomata typically close in plants?

  At night when it's dark
• What is the primary function of palisade mesophyll in leaves?

  Photosynthesis
• What is the role of spongy mesophyll in leaves?

  It contains air spaces for gas exchange
• What are the three features required for effective gas exchange surfaces?

  Large surface area, short diffusion distance, concentration gradient
• How does the concentration gradient affect gas exchange?

  A higher gradient increases the rate of diffusion
• What are the adaptations of terrestrial insects for gas exchange?

  • Large number of fine tracheals
  • Thin walls for short diffusion distance
  • Spiracles can open and close to limit water loss
• What adaptations do fish have for gas exchange?

  • Gills with large surface area
  • Short diffusion distance due to capillary network
  • Counter current flow mechanism to maintain concentration gradient
• What are the adaptations of leaves for gas exchange?

  • Palisade mesophyll for photosynthesis
  • Spongy mesophyll with air spaces
  • Stomata for gas diffusion
• What is the primary function of gill lamellae in fish?

  Maintain concentration gradient for oxygen
• What are the main structures involved in gas exchange in leaves?

  • Palisade mesophyll: site of photosynthesis
  • Spongy mesophyll: contains air spaces
  • Stomata: gas exchange occurs here
• What happens to oxygen during gas exchange in leaves?

  Oxygen diffuses out of stomata
• When do stomata close and why?

  Stomata close at night to reduce water loss
• What are xerophytic plants adapted to do?

  Minimize water loss in dry environments
• What adaptations do xerophytic plants have to reduce water loss?

  • Leaves roll up
  • Deep, sunken stomata
  • Tiny hairs on leaves
  • Thicker cuticle
  • Longer root networks
• What is the process of digestion in terms of biological molecules?

  Large molecules are hydrolyzed into smaller ones
• What are the three biological molecules involved in digestion?

  • Carbohydrates
  • Lipids
  • Proteins
• Where does carbohydrate digestion begin?

  In the mouth with amylase
• What enzyme is produced by the salivary gland for carbohydrate digestion?

  Amylase
• What is the role of bile salts in lipid digestion?

  Emulsify lipids to increase surface area