metabolism

    Cards (9)

    • metabolism is all the chemical reactions in an organism.
    • in a cell there are lots of chemical reactions happening all the time, which are controlled by enzymes.
    • many of these reactions are linked together to form bigger reactions: -reactant -enzyme-> product -enzyme-> product -enzyme-> product.
    • in some of these reactions, larger molecules are made from smaller ones.
      • lots of small glucose molecules are joined together in reactions to form starch (a storage molecule in plant cells), glycogen (a storage molecule in animal cells) and cellulose ​(a component of plant cell walls).
      • lipid molecules are each made from one molecule of glycerol and three fatty acids.
      • glucose is combined with nitrate ions to make amino acids, which are then made into proteins.
    • in other reactions, larger molecules are broken down into smaller ones
      • glucose is broken down in respiration. respiration transfers energy to power all the reactions in the body that make molecules.
      • excess protein is broken down in a reaction to produce urea. urea is then excreted in urine.
    • the sum (total) of all the reactions that happen in a cell or the body is called metabolism.
    • independent variable - the thing that is controlled
      dependent variable - the thing being measured
      control variable - the thing that doesn't change
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