ACTIVE TRANSPORT

• What is active transport?

  Active transport is the movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher concentration.
• Why does active transport require energy?


  Active transport requires energy to move substances against their concentration gradient.
• What is hydrolysis in the context of ATP?


  Hydrolysis is the process where high energy phosphate bonds in ATP are broken to release energy.
• What is the chemical equation for the hydrolysis of ATP?


  ATP → ADP + Pi
• Why is ATP used as a source of energy in organisms?


  ATP is used because it provides a readily available source of energy for cellular processes.
• What is required for active transport to occur?


  Active transport requires carrier proteins.
• How does a carrier protein function in active transport?


  A carrier protein changes shape to transfer specific molecules or ions across the cell membrane.
• What is endocytosis?


  Endocytosis is the process where the cell surrounds a substance with a section of the cell membrane and engulfs it to form a vesicle.
• Why do some molecules require endocytosis to enter the cell?


  Some molecules are too large to travel via membrane proteins.
• What is exocytosis?


  Exocytosis is the process where vesicles containing substances fuse with the cell surface membrane to release their contents outside the cell.
• What types of substances are typically secreted by exocytosis?


  Substances such as hormones, some enzymes, and lipids are secreted by exocytosis.
• What is the role of ATP in exocytosis?


  Exocytosis is an active process that requires ATP for energy.
• What is a vesicle?


  A vesicle is a small membrane-bound sac that transports substances within a cell.
• What is bulk transport?


  Bulk transport refers to the movement of large quantities of substances into or out of the cell.
• What is the purpose of endocytosis?


  Endocytosis allows the cell to take in large substances that cannot pass through the membrane directly.
• Describe how endocytosis occurs.

  The cell membrane surrounds a substance, engulfs it, and forms a vesicle containing the ingested substance.
• What is the difference between endocytosis and exocytosis?

  Endocytosis involves taking substances into the cell, while exocytosis involves releasing substances from the cell.
• Describe how exocytosis occurs.

  Vesicles containing substances move toward and fuse with the cell surface membrane to release their contents outside the cell.
• What is the structure of the cell membrane?

  The cell membrane is composed of a phospholipid bilayer with embedded proteins.
• Compare the role of the cell membrane in exocytosis and endocytosis.


  The cell membrane engulfs substances in endocytosis and releases substances in exocytosis.
• Compare and contrast the processes of endocytosis and exocytosis.

  • Endocytosis:
  • Involves taking substances into the cell
  • Forms vesicles from the cell membrane
  • Exocytosis:
  • Involves releasing substances from the cell
  • Vesicles fuse with the cell membrane to release contents
• What types of substances can be transported by simple diffusion?

  Simple diffusion typically transports small nonpolar molecules and gases.
• Describe a use of active transport in animals.

  Active transport is used in animals for the uptake of glucose in the intestines.
• Describe a use of active transport in plants.

  Active transport is used in plants to absorb minerals from the soil against their concentration gradient.
• What is facilitated diffusion?

  Facilitated diffusion is the process where molecules pass through the cell membrane via specific transport proteins without energy input.
• What is a similarity between active transport and facilitated diffusion?

  Both processes involve the movement of molecules across the cell membrane.
• What is one difference between active transport and facilitated diffusion?

  Active transport requires energy, while facilitated diffusion does not.
• Describe the difference between channel and carrier proteins.

  Channel proteins form pores for passive transport, while carrier proteins change shape to transport specific molecules.
• Compare and contrast active transport and simple diffusion.

  Active transport requires energy and moves substances against their gradient, while simple diffusion is passive and moves substances down their gradient.