Exchange

• How do you work out volume?

  Volume = length x width x height
• How do you calculate surface area?

  Surface area = area of sides added up
• What is the surface area to volume ratio of smaller organisms?

  They have higher surface area to volume ratio
• How does surface area to volume ratio relate to metabolic rate?

  Higher SA:V increases heat loss, needing higher metabolic rate
• Why do larger organisms need specialized exchange systems?

  They have smaller SA:V and long diffusion pathways
• What are the adaptations of a single-celled organism?

  Thin flat shape, large SA:V, short diffusion distance
• How does oxygen and CO2 move in and out of insects?

  Air moves through spiracles and trachea to cells
• How is a concentration gradient established in insects for gas exchange?

  O2 used by cells creates a gradient for diffusion
• What adaptations do insects have for gas exchange?

  Thin tracheoles, high number, muscle contractions
• What adaptations do fish have for gas exchange?

  Many filaments and lamellae increase surface area
• How does counter current flow in fish work?

  Blood and water flow in opposite directions
• What happens if water and blood flow in the same direction in fish?

  Equilibrium is reached, oxygen won't diffuse
• What are the layers of a leaf?

  Waxy cuticle, upper epidermis, mesophyll, lower epidermis
• What adaptations do plants have for gas exchange?

  Many stomata, air spaces, thin structure
• What adaptations do xerophytes have?

  Thick cuticle, stomata in pits, rolled leaves
• When do gases diffuse in and out of leaves?

  O2 through stomata during the day, closed at night
• What is the path of oxygen into the lungs?

  Trachea, bronchi, bronchioles, alveoli
• How are the lungs adapted for gas exchange?

  Many alveoli, thin walls, ventilation maintains gradient
• What are adaptations of alveoli for gas exchange?

  Thin walls, good blood supply,
• What happens during inspiration?

  External intercostal muscles contract, ribcage moves up
• How does expiration work?

  Internal intercostal muscles contract, ribcage moves down
• What does ventilation consist of and why is it needed?

  Inhalation and expiration maintain O2 concentration gradient
• What is tidal volume?

  Volume of air in each breath
• What is ventilation rate?

  Number of breaths per minute
• What is forced expiratory volume?

  Maximum volume of air breathed out in 1 sec
• What is forced vital capacity?

  Maximum volume of air breathed out in a single breath
• What are the effects of reduced elasticity on ventilation?

  Reduced tidal volume and forced vital capacity
• What are the effects of thicker alveoli on gas exchange?

  Increased diffusion distance reduces gas exchange rate
• What happens when cells receive less oxygen?

  Rate of aerobic respiration is reduced, less ATP
• What happens during digestion?

  Large insoluble molecules are broken down into smaller soluble molecules
• Why do food molecules need to be digested?

  Large molecules can't cross cell membranes for absorption
• What are the two types of digestion?

  Physical digestion and chemical digestion
• What enzyme breaks down carbohydrates?

  Amylase
• Where is amylase produced?

  Salivary glands, pancreas, small intestine
• What does amylase hydrolyze starch to?

  Maltose
• Which enzymes hydrolyze disaccharides?

  Maltase, sucrase, lactase
• What do endopeptidases do?

  Hydrolyze peptide bonds within proteins
• What do exopeptidases do?

  Hydrolyze peptide bonds at the ends of protein molecules
• What do dipeptidases do?

  Hydrolyze peptide bonds between a dipeptide
• How are lipids digested?

  Bile salts emulsify lipids, lipase hydrolyzes them