AQA GCSE Combined Science Biology - Paper 1

• What equipment is used to control temperature in an investigation?

  Water bath
• Why must hydrochloric acid from the stomach be neutralised by bile in the small intestine?

  So that enzymes aren't denatured
• What is the purpose of emulsification

  To break large fats into small droplets, to increase surface area for lipase
• Give two functions of bile

  To emulsify fats, and to neutralise stomach acid
• Where is bile stored?

  Gall bladder
• Where is bile made?

  Liver
• What are the products of lipase digesting lipids?

  Glycerol and fatty acids
• What are the products of protease digesting proteins?

  Amino acids
• What are the products of amylase digesting starch?

  Glucose
• What is the substrate of carbohydrase?

  Carbohydrate
• What is the substrate of lipase?

  Lipids (fats)
• What is the substrate of protease?

  Protein
• What is the substrate of amylase?

  Starch
• Where is lipase made?

  Pancreas and Small intestine
• Where is protease made?

  Stomach and small intestine
• Where is amylase made?

  Salivary glands and pancreas
• What is the purpose of digestion

  To break large, insoluble molecules into small, soluble molecules so they can be absorbed
• What is the Lock and Key Theory?

  A substrate is specific to one enzyme because of the specific shape of its active site (like a key fitting a lock)
• What is human body temperature?

  37oC
• Define denature


  When an enzyme cannot work because its active site has lost its specific shape so the substrate no longer fits
• What conditions cause enzymes to denature?

  High temperatures or pH that is too high or low
• What are enzymes made of?

  Protein
• Why are enzymes specific?

  Each type of enzyme has an active site that only fits one specific substrate
• What is formed when an enzyme binds to a substrate?

  Enzyme-substrate complex
• Where does a substrate bind to an enzyme?

  Active site
• What is a substrate?

  A substance that is broken down by an enzyme
• Define an enzyme

  A biological catalyst that carries out metabolic reactions in living organisms
• Give two examples of organs in plants

  Leaf, root, stem, flower
• Give two examples of organs in animals

  Heart, lungs, stomach, brain, liver
• Give two examples of tissues in plants

  Palisade tissue, spongy mesophyll tissue, xylem tissue, phloem tissue
• Give two examples of tissues in animals

  Epithelial tissue, muscle tissue, nerve tissue, glandular tissue
• Deine an organ system


  A group of organs working together
• Define an organ

  A group of tissues working together to perform a function
• Define a tissue

  A group of cells with similar structure and function
• Explain one example of active transport in animals


  Absorption of glucose in the small intestine
• Explain one example of active transport in plants


  Absorption of mineral ions in root hair cells
• Define active transport

  The movement of particles from a low concentration to a high concentration against a concentration gradient, using energy
• Why do you calculate %change in mass of a potato chip rather than just change in mass?

  So that you can compare different chips, as the starting mass of each potato may not be the same
• Why should you blot a potato chip dry before taking its mass?

  To remove excess water, so it doesn't increase the mass
• How would you calculate % change in mass of a potato chip in sucrose solution?

  (Change in mass ÷ Starting mass) x 100