transport within body

• what is simple diffusion?

  net movement of molecules from higher concentration to lower ( no ATP)
• what is facilitated diffusion?

  passive process , uses channel and carrier proteins to transport molecules
• what does a channel protein do?


  forms tubes of water allowing water soluble ions through , selective process
• how do carrier proteins work?

  protein binds with molecule causing it to change shape this allows the molecule to be released on the other side
• what is osmosis?


  movement of molecules from high water potential to low through a partially permeable memebrane
• what does isotonic mean?

  same water potential as solute
• what is hypotonic?


  more positive water potential
• what is hypertonic?


  more negative water potential
• what is active transport?

  movement of molecules from a lower concentration to higher using ATP and carrier proteins
• what is digestion?


  large insoluble molecules being hydrolysed into smaller molecules which can be absorbed
• what digests carbohydrates?


  amylase and membrane bound disachharides
• where is amylase produced?

  pancreas and salivary glands
• hydrolysis of carbohydrates?


  amylase hydrolyses polysaccharides into disaccharides by hydrolysing glycosidic bonds

  membrane bound enzymes hydrolyse disaccharides into monosacccharides
• where does carbohydrate digestion begin and end?

  mouth and ileum
• where does protein digestion start and end?

  stomach and ileum
• what does endopeptidase do?


  hydrolyses peptide bonds between ammino acids in the middle of a polypeptide
• what does exopeptidase do?

  Hydrolyzes peptide bonds at the ends of polypeptide chains.
• what does membrane bound dipeptidase do?

  hydrolyses peptide bond between 2 ammino acids
• where is lipase produced?


  pancreas
• what does lipase do ?

  hydrolyses the ester bond in triglycerides to form monoglycerides and fatty acids
• where are bile salts produced?

  liver
• what do bile salts do ?

  emulsify lipids to form micelles increasing surface area for lipase
• what are micelles?


  water soluble vesicles that deliver fatty acids and glycerol to epithelial cells for absorption