Biology: Enzymes and digestion

  • Created by: N.A.N.A.
  • Created on: 26-11-19 20:25
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      • Digestive enzymes are protease, lipase and carbohydrase
        • Protease digests proteins, lipase digests lipids, carbohydrase digests carbohydrates, the products can be used to build new carbohydrates, lipids and proteins
          • Amalayse produced in pancreas and salivary glands, breaks down starch into sugar (maltose)
          • Protease produced in pancreas stomach, and small intestine, breaks down proteins into amino acids (or peptides)
          • Lipase produced in pancreas and small intestine, breaks down lipids into fatty acids and glycerol
        • Enzymes pass out of cells into digestive system, catalsye the breakdown of large insoluable food molecules to smaller soluable molecules
          • Digestive enzymes are produced by specialised cells in glands and lining of gut
        • Required practical: reagents to test for proteins, lipids and carbohydrates
          • Test for sugar: add Benedict's   reagent (heat in water bath for two minutes) , will turn brick red if present
          • Test for starch: Add Iodine solution, will turn blue black if present
          • Test for protein: Add Biuret reagent, will turn purple if present
      • Biological catalysts that speed up chemical reactions in living organisms
      • Properties of enzymes: all large proteins, space in protein molecule called active site, each catalyses specific reaction, work best at optimum (temperature and pH)
        • Lock and key theory: substrate (key) fits into enzymes active site (lock)
        • High temperatures and extreme pHs denature the enzyme (make it change shape so it doesn't fit substrate)
    • BILE
      • Liquid made in the liver and stored in gall bladder
        • Is an alkaline used to neutralise hydrochloric acid from the stomach
        • Emulsifies fat to form small droplets meaning a larger surface area for enzymes (lipase) to act on
      • A tissue is a group of cells with similar functions that work together to do a similar structure and function
        • Muscle tissue contracts to bring about movement
        • Glandular tissue produces substances like enzymes and hormones
        • Epithelial tissue covers organs
      • Organs are groups of different tissues that work together to do a specific job
        • In the stomach: muscle churns food, glandular tissue secretes digestive juices and epithelial tissue covers inside and outside lining
      • Organ systems are groups of organs working together to do a particular job
        • Digestive system is an organ system, lots of organ systems work together to form an organism
  • Nana Agyemang


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