surface area to volume ratio

• What concept explains why multicellular organisms require exchange surfaces and a transport system?

  Surface area to volume ratio
• How do gills increase the rate of gas transport in fish?

  They provide a large surface area for gas exchange
• What is the process by which molecules move in and out of cells?

  Diffusion
• What happens to oxygen and carbon dioxide during diffusion in cells?

  Oxygen diffuses into cells and carbon dioxide diffuses out
• What is the surface area to volume ratio of a cube with a side length of 1 mm?


  1. 1
• How do you calculate the surface area of a cube with a side length of 1 mm?

  Surface area = 6 * (1 mm * 1 mm) = 6 mm²
• What is the volume of a cube with a side length of 1 mm?

  Volume = 1 mm * 1 mm * 1 mm = 1 mm³
• What is the surface area to volume ratio of a cube with a side length of 2 mm?

  1. 1
• How do you calculate the surface area of a cube with a side length of 2 mm?

  Surface area = 6 * (2 mm * 2 mm) = 24 mm²
• What is the volume of a cube with a side length of 2 mm?

  Volume = 2 mm * 2 mm * 2 mm = 8 mm³
• What is the surface area to volume ratio of a cube with a side length of 3 mm?

  1. 1
• Why do multicellular organisms face challenges with gas exchange?

  Their surface area is not large enough for their volume
• How do animals solve the problem of gas exchange?

  By having specialized structures and a transport system
• How do fish obtain oxygen from water?

  Oxygen-rich water passes into the mouth and flows over gills
• What adaptations do gills have to facilitate gas exchange?

  They have a large surface area, thin membranes, and an efficient blood supply
• What role does the concentration gradient play in gas exchange in gills?

  It ensures that oxygen diffuses efficiently into the blood
• What are the key adaptations of gills that enhance diffusion?


  • Large surface area
  • Thin membranes for short diffusion pathway
  • Efficient blood supply to maintain concentration gradient
• What is the relationship between surface area to volume ratio and organism size?

  • As organisms increase in size, the surface area to volume ratio decreases sharply
  • Larger organisms face challenges in gas exchange due to insufficient surface area
• Why do multicellular organisms require specialized exchange surfaces?

  • To facilitate efficient gas exchange
  • To ensure adequate transport of gases to all cells
• How do lungs in mammals assist in gas exchange?

  • They provide a large surface area
  • They have thin walls for efficient diffusion
  • They are connected to a transport system (circulatory system)