Topic 3

• What is the relationship between surface area and volume in organisms?

  Larger organisms have a lower surface area to volume ratio
• Why do small organisms like amoeba not need special adaptations for gas exchange?

  They have a large surface area compared to volume
• What is a key adaptation for larger organisms regarding gas exchange?

  They require adaptations for mass transport
• What are some key adaptations for gas exchange in different organisms?

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

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

  Gas exchange is diffusion of gases
• What are the key structures of the human gas exchange system?

  Alveoli, bronchioles, bronchi, trachea, lungs
• What muscle is primarily involved in human ventilation?

  The diaphragm
• What does the term antagonistic mean in muscle function?

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

  External intercostal muscles contract, ribcage expands
• What occurs to the thorax volume during inhalation?

  The volume of the thorax increases
• How is pulmonary ventilation calculated?

  Tidal volume times ventilation rate
• What is the total volume of air moved into the lungs during one minute called?

  Pulmonary ventilation
• What is the role of alveoli in gas exchange?

  Site of gas exchange between air and blood
• How many alveoli are in each lung?

  Around 300 million
• Why do alveoli float in water?

  They are filled with air
• What is the function of the tracheal system in insects?

  Facilitates ventilation and gas exchange
• What are spiracles in insects?

  Valves for gas exchange openings
• Why is there always a higher concentration of oxygen in water compared to blood?

  Because of the diffusion gradient across gill lamellae
• What are the main structures involved in gas exchange in leaves?

  • Palisade mesophyll
  • Spongy mesophyll
  • Stomata
• What is the primary function of the palisade mesophyll in leaves?

  It is where photosynthesis mainly occurs
• What happens to stomata at night?

  They close to reduce water loss
• How do xerophytic plants minimize water loss?

  They have adaptations like rolled leaves and sunken stomata
• What is the role of the cuticle in xerophytic plants?

  To reduce water loss
• What is the process of digestion in terms of biological molecules?

  Large molecules are hydrolyzed into smaller soluble molecules
• 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 pancreas for carbohydrate digestion?

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

  To emulsify lipids into micelles
• What is the function of lipase in digestion?

  To hydrolyze triglycerides into monoglycerides
• What are the steps of lipid absorption in the ileum?

  1. Lipids are digested into monoglycerides and fatty acids
  2. They diffuse across the epithelial cell membrane
  3. Inside the cell, they are reformed into triglycerides
  4. Triglycerides are packaged into vesicles and released into the lacteal
• What adaptations do villi and microvilli provide in the ileum?

  They increase surface area for absorption
• How do monosaccharides like glucose enter epithelial cells?

  Through active transport via co-transport
• What is hemoglobin's role in the body?

  To transport oxygen around the body
• What is the structure of hemoglobin?

  It is a quaternary structure protein
• What does the oxyhemoglobin dissociation curve illustrate?

  How hemoglobin behaves under different oxygen pressures
• What happens to hemoglobin in areas with high partial pressure of oxygen?

  It loads oxygen efficiently
• What is the Bohr effect?

  High CO2 concentration shifts the dissociation curve right
• How does fetal hemoglobin differ from adult hemoglobin?

  • Higher affinity for oxygen
  • Loads oxygen more efficiently from maternal blood
• Why do llamas have a different type of hemoglobin?

  To adapt to low oxygen at high altitudes