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 the energy source for active transport?

  Energy from respiration
• What is a concentration gradient?

  Difference in concentration across a space
• If a cell needs to absorb glucose from a low concentration, what process does it use?

  Active transport
• What are the key differences between diffusion and active transport?

  • Diffusion: moves down concentration gradient
  • Active transport: moves against concentration gradient
  • Diffusion: does not require energy
  • Active transport: requires energy from respiration
• Why do cells lining the small intestine have many mitochondria?

  To provide energy for active transport
• What is the lumen in the context of the small intestine?

  The cavity where food is digested
• How do root hair cells use active transport?

  To absorb ions like magnesium from soil
• Why do plants need magnesium ions?

  To make chlorophyll in the leaves
• What do root hair cells transport into the plant?

  Ions such as magnesium
• What happens to ions after they are absorbed by root hair cells?

  They are transported to the xylem vessels
• What do root hair cells have to provide energy for active transport?

  Lots of mitochondria