Surface area to volume ratio

• Why can single-celled bacteria rely on diffusion?

  They have a high surface area to volume ratio
• What do large multicellular organisms require for substance exchange?

  Specialized exchange surfaces and transport systems
• What resources do single-celled organisms absorb from their surroundings?

  Oxygen, glucose, and amino acids
• What waste products do single-celled organisms need to eliminate?

  Carbon dioxide
• How does surface area to volume ratio affect organisms?

  It determines their ability to exchange substances
• What happens to the surface area to volume ratio as organisms get larger?

  It decreases
• Why is it hard to calculate the surface area and volume of real organisms?

  They have irregular shapes
• How do you calculate the surface area of a cube?

  Area of one face times six
• What is the surface area of a 1 cm cube?

  6 square centimeters
• What is the volume of a 1 cm cube?

  1 cubic centimeter
• Why do larger organisms need specialized exchange surfaces?

  To increase their surface area to volume ratio
• What structures in the lungs increase surface area for gas exchange?

  Alveoli
• What structures in the intestines enhance nutrient absorption?

  Villi
• How does diffusion distance change with organism size?

  It increases significantly in larger organisms
• Why can't larger organisms rely solely on diffusion?

  Diffusion is too slow over long distances
• What systems do larger organisms use to transport substances?

  Transport systems like the circulatory system
• What do plants use for substance exchange with the environment?

  Roots and leaves
• What tissues do plants use to transport substances?

  Phloem and xylem
• What does the term "large organisms" refer to?

  Anything visible to the naked eye