Active Transport

• What process allows substances to be absorbed against a concentration gradient?

  Active transport
• How does active transport differ from diffusion?

  Active transport moves substances against the gradient
• What is a concentration gradient?

  Difference in concentration across a space
• What is the energy source for active transport?

  Energy from respiration
• If a cell needs to absorb glucose from a low concentration, what process does it use?

  Active transport
• Why can't glucose diffuse into the cell from the lumen?

  Because its concentration is lower in the lumen
• What do the cells lining the human small intestine absorb?

  Glucose and other sugars
• What role do mitochondria play in active transport?

  They provide energy for the process
• What ions do root hair cells transport into plants?

  Magnesium ions
• Why do plants need magnesium ions?

  To make chlorophyll in leaves
• How do root hair cells use active transport?

  To move ions from soil into the cell
• How does the concentration of ions in soil compare to that in root hair cells?

  Lower concentration in soil than in cells
• What are the key differences between active transport and diffusion?

  • Active transport moves substances against the gradient
  • Diffusion moves substances down the gradient
  • Active transport requires energy from respiration
  • Diffusion does not require energy