Metabolism

• What is metabolism?


  All the chemical reactions in an organism
• How are chemical reactions in a cell controlled?


  They are controlled by enzymes
• What is the relationship between smaller and larger molecules in metabolism?


  Smaller molecules can be joined to form larger molecules
• What are examples of larger molecules formed from smaller ones in metabolism?


  • Starch from glucose (storage in plants)
  • Glycogen from glucose (storage in animals)
  • Cellulose from glucose (component of plant cell walls)
  • Lipids from glycerol and fatty acids
  • Amino acids from glucose and nitrate ions
• What is starch and where is it found?


  Starch is a storage molecule found in plant cells
• What are lipids made from?


  Lipids are made from one molecule of glycerol and three fatty acids
• How are amino acids formed in metabolism?


  Amino acids are formed by combining glucose with nitrate ions
• What happens to glucose during respiration?


  Glucose is broken down to transfer energy
• What is produced when excess protein is broken down?


  Urea is produced and excreted in urine
• What is the sum of all reactions in a cell called?

  Metabolism
• Why is it important to understand enzymes in relation to metabolism?


  Enzymes are key to metabolism
• What should you do if you need a reminder about enzymes?


  Refer back to page 42
• Why is it important to check your understanding of respiration?


  Respiration is important for metabolism