Metabolism: Bioenergetics: Biology: GCSE (9:1)

• Metabolism


  The sum of all the reactions in a cell or the body
• Metabolism includes

  The synthesis of new molecules, the breakdown of existing molecules and the process of respiration
• Energy transferred by cellular respiration


  Is used by organisms for the continual enzyme-controlled processes of metabolism
• Enzymes and metabolism

  Enzymes regulate most cellular reactions and are essential for the synthesis and breakdown of molecules

  
• Conversion of glucose to complex carbohydrates

  Glucose can be converted into starch, glycogen and cellulose

  
• Formation of lipid molecules

  One molecule of glycerol joins with three fatty acids

  
• Amino acid production

  Glucose and nitrate ions form amino acids which are used to make proteins

  
• Protein synthesis

  Amino acids join together in specific arrangements to form proteins

  
• Urea excretion

  Excess proteins are broken down to form urea for excretion

  
• Digestion


  Requires energy from respiration to break down large insoluble molecules into smaller soluble molecules

  
• Carbohydrates


  Provide energy for chemical reactions and can break down into sugars

  
• Proteins

  The building blocks of cells and tissues that can break down into amino acids

  
• Lipids


  An energy store of fats and oils that can break down into glycerol and fatty acids