Topic 8: Exchange & Transport in Animals

• Why is it necessary to transport substances into organisms?

  To provide vital elements for life and remove waste products
• What do plants need to take in during photosynthesis?

  Carbon dioxide and dissolved nutrients
• What is the role of the kidney in animals?

  To efficiently remove waste such as urea and excess ions
• What happens if excess urea is not removed from the body?

  It builds up and becomes toxic
• What condition can result from excess carbon dioxide in the blood?

  Acidosis
• What are the characteristics of specialised exchange surfaces?

  • Short distance for diffusion
  • Large surface area
• What is the function of root hair cells in plants?


  To take up water and nutrients from the soil
• How do the walls of nephrons in the kidney aid in substance reabsorption?

  They have thin walls and a large surface area
• What is the role of alveoli in the lungs?

  To transfer oxygen to the blood and carbon dioxide to the lungs
• What are villi in the small intestine responsible for?

  Absorbing digested food into the bloodstream
• How do fish gills facilitate gas exchange?

  Water flows over the gills while blood flows in the opposite direction
• What is the function of stomata in plant leaves?

  To allow gas exchange for photosynthesis
• How do guard cells regulate stomata size?

  By swelling with water to make stomata larger
• What adaptations do organisms have for efficient diffusion?

  • Large surface area
  • Thin membranes
  • Efficient blood supply or ventilation
• What does a large surface area to volume ratio indicate about an organism?

  It is less likely to require specialised exchange surfaces
• How is the surface area to volume ratio calculated?

  By comparing the surface area to the volume of the organism
• Why can't multicellular organisms rely solely on diffusion?

  They have a small surface area to volume ratio
• What are alveoli?

  Small air sacs in the lungs
• What factors affect the rate of diffusion?

  • Concentration gradient
  • Temperature
  • Surface area
  • Thickness of the membrane

  
• What components make up blood?

  Plasma, red blood cells, white blood cells, and platelets
• What is the function of plasma in blood?

  To carry blood components and nutrients
• What is the role of red blood cells?

  To carry oxygen from the lungs to cells
• How does the biconcave shape of red blood cells benefit their function?

  It provides a large surface area for oxygen transport
• What is the function of white blood cells?

  To defend against pathogens
• What do platelets do in the blood?

  Help form clots at wound sites
• What are the three types of blood vessels and their functions?

  1. Arteries: Carry blood away from the heart
  2. Veins: Carry blood towards the heart
  3. Capillaries: Allow exchange of substances between blood and cells
• What is the function of arteries?

  To carry blood away from the heart
• How do veins ensure blood flows in the right direction?

  They have valves
• What is the role of capillaries in the circulatory system?

  To enable substance exchange between blood and cells
• What is the structure and function of the heart?

  • Pumps blood in a double circulatory system
  • Has 4 chambers to separate oxygenated and deoxygenated blood
  • Contains valves to prevent backflow
• What happens to deoxygenated blood in the heart?

  It flows into the right atrium and then to the lungs
• What is the function of the pacemaker in the heart?

  To control the natural resting heart rate
• What is an artificial pacemaker used for?

  To regulate an irregular heartbeat
• What is respiration and its types?

  • Process of transferring energy from glucose
  • Types: Aerobic (with oxygen) and Anaerobic (without oxygen)
• What is the equation for aerobic respiration?

  $C_6H_{12}O_6 +$$O_2 \rightarrow CO_2 +$$H_2O$
• What is produced during anaerobic respiration in animals?

  Lactic acid
• What is fermentation in plants and yeast?

  Glucose is converted to ethanol and carbon dioxide
• What is the equation for calculating cardiac output?

  Cardiac output = stroke volume × heart rate
• What is stroke volume?

  The volume of blood expelled from the heart in one contraction
• What is heart rate?

  The number of contractions (beats) per minute