biology- gas exchange

    Cards (56)

    • What is the relationship between surface area and volume in smaller single-celled organisms?
      They have a high surface area to volume ratio
    • How do smaller single-celled organisms absorb oxygen?
      By diffusion across their body surface
    • What happens to carbon dioxide produced during respiration in single-celled organisms?
      It diffuses out across the body surface
    • Why is gas exchange harder when there is low oxygen?
      Because diffusion rates decrease with low concentration
    • What structures do insects use for gas exchange?
      Tracheae and tracheoles
    • How are tracheae supported in insects?
      By strengthened rings to prevent collapsing
    • What is the function of tracheoles in insects?
      They extend throughout all body tissues
    • How does atmospheric air reach respiring tissues in insects?
      Through a short diffusion pathway from tracheoles
    • What is a spiracle in insects?
      A tiny pore for gas entry
    • When does a spiracle close in insects?
      When the insect is inactive or hot
    • How does gas movement occur in the tracheal system of insects?
      Along a diffusion gradient
    • What happens to oxygen concentration in tracheoles during respiration?
      It falls as oxygen is used up
    • How does carbon dioxide move in the tracheal system?
      It diffuses out in the opposite direction
    • What is mass transport in the context of insect respiration?
      Contraction of muscles squeezing tracheae
    • What happens to water in tracheoles during major activity?
      It moves into muscle cells by osmosis
    • Why can't there be 'giant insects'?
      Because diffusion limits their size
    • How are fish gills adapted to maximize gas exchange?
      • Large surface area with many filaments
      • Short diffusion pathway with thin walls
      • Maintained concentration gradient
      • Countercurrent flow of water and blood
    • What is ram ventilation in fish?
      Swimming with mouth open for water flow
    • How does water enter a fish?
      Through the mouth when it opens
    • What happens when a fish closes its mouth?
      The operculum opens to release water
    • What adaptations do gill filaments have for gas exchange?
      Large surface area and many capillaries
    • How is a concentration gradient maintained in fish gills?
      By continuous flow of water and blood
    • What is the countercurrent system in fish gills?
      Water and blood flow in opposite directions
    • Why is equilibrium never reached in fish gills?
      Because oxygen constantly diffuses in
    • How does abdominal pumping increase gas exchange efficiency in insects?
      It brings air directly to respiring tissues
    • How do small insects obtain sufficient oxygen without abdominal pumping?
      By having a larger surface area to volume ratio
    • What is the frequency of spiracle opening in the insect at rest?
      7 times per minute
    • Why does an insect open its spiracles less in dry conditions?
      To prevent water loss while taking in oxygen
    • What happens to the ends of tracheoles during flight?
      Water is absorbed into muscle tissue
    • How does the removal of water from tracheoles affect gas diffusion?
      It increases the rate of diffusion of oxygen
    • What is the formula for calculating surface area to volume ratio?
      SA:V ratio = surface area / volume
    • How does metabolic rate relate to body mass?
      Higher mass generally means higher metabolic rate
    • Why do smaller animals have a higher basal metabolic rate per unit mass?
      Due to higher surface area to volume ratio
    • What are the adaptations of the alveoli for gas exchange?
      • Large surface area
      • Thin walls (one cell thick)
      • High concentration gradient maintained
      • Rich blood supply
    • What is the role of the diaphragm during inhalation?
      It contracts and flattens to increase lung volume
    • What occurs during exhalation?
      Diaphragm relaxes, increasing lung pressure
    • What is pulmonary ventilation?
      Total air moved into lungs per minute
    • How is the pathway of an oxygen molecule described?
      Across alveolar epithelium and capillary endothelium
    • What is the significance of the alveolar epithelium being one cell thick?
      It shortens the diffusion pathway for gases
    • What happens to the pressure in the lungs during inhalation?
      It decreases as lung volume increases
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