Membranes and transport.

  • Created by: Pudgee
  • Created on: 24-10-17 14:17


  • are partially permeable so regulate the transport of molecules in and out of the cell.
  •  separates cell components from the external environment.
  • may contain enzymes involved in specific metabolic pathways.
  • has antigens so the immune system will recognise the cell as self and not attack. 
  • may release chemicals to signal other cells
  • contains receptors for such signals, and so is a site for cell communication or signalling; hormones and drugs may bind to receptors.
  • may be the site of chemical reactions.
  • form cristae in mitochondria that give a large surface area for aerobic respiration
  • inner membranes of chloroplasts called thylakoid membranes house chlorophyll. 
  • the membranes of epithelial cells that line the small intestine contain some enzymes that catalyse some of the final stages in the breakdown of certain types of sugars


  • phospholipid molecules
  • channel protein
  • carrier protein
  • cholesterol
  • glycoproteins and glycolipids that form the glycocalyx used for signalling and attracting solutes.


Simple diffusion

  • all molecules have kinetic energy and can move freely and randomly. 
  • if there is a high concentration of a molecule they will bump into each other and…


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