TOPIC B2- organisation

• What is the basic building block of all living organisms?


  Cells
• What is the process called when cells become specialized for a particular job?

  Differentiation
• What do specialized cells form?

  Tissues
• How are large multicellular organisms organized?

  • Cells form specialized cells
  • Specialized cells form tissues
  • Tissues form organs
  • Organs form organ systems
• What is a tissue?

  A group of similar cells that work together
• What are examples of tissue in mammals?

  Muscular, glandular, and epithelial tissue
• What is an organ?

  A group of different tissues working together
• What tissues make up the stomach?

  Muscular, glandular, and epithelial tissue
• What is an organ system?

  A group of organs working together
• What is the function of the digestive system?

  To break down and absorb food
• What organs make up the digestive system?

  • Glands (e.g. pancreas, salivary glands)
  • Stomach
  • Small intestine
  • Liver
  • Large intestine
• What are enzymes?

  Catalysts produced by living things
• Why are enzymes important for chemical reactions in living organisms?

  They speed up reactions without being changed or used up
• What are enzymes made of?

  Large proteins made of chains of amino acids
• What is the active site of an enzyme?

  The unique shape that fits onto the substrate involved in a reaction
• What happens if the substrate does not fit into the enzyme's active site?

  The reaction will not be catalyzed
• What is the 'lock and key' model of enzyme action?

  It describes how the active site fits the substrate perfectly
• What is the 'induced fit' model of enzyme action?

  The active site changes shape slightly to fit the substrate better
• How does temperature affect enzyme activity?

  Higher temperatures increase reaction rates until the enzyme denatures
• What is denaturation in enzymes?

  When the enzyme's active site changes shape and no longer fits the substrate
• What is the optimum temperature for enzymes?

  The temperature at which an enzyme is most active
• How does pH affect enzyme activity?

  Extreme pH levels can denature enzymes by changing their active site shape
• What is bile's function in digestion?

  To neutralize stomach acid and emulsify fats
• Where is bile produced and stored?

  Bile is produced in the liver and stored in the gall bladder
• What is the role of digestive enzymes?

  To break down large food molecules into smaller, absorbable molecules
• What is amylase and where is it produced?

  A carbohydrase that breaks down starch, produced in the salivary glands, pancreas, and small intestine
• What do proteases do?

  They convert proteins into amino acids
• Where are lipases produced?

  In the pancreas and small intestine
• What are the steps to investigate the effect of pH on enzyme activity?

  1. Prepare iodine solution in wells
  2. Heat water in a beaker
  3. Mix amylase and buffer solution in a boiling tube
  4. Add starch solution and start timing
  5. Sample every 30 seconds to check for starch
  6. Repeat with different pH values
  7. Control variables for a fair test
• How do you calculate the rate of reaction?

  Rate = change ÷ time
• If 24 cm³ of oxygen is released in 50 seconds, what is the rate of reaction?

  0.48 cm³ s⁻¹
• What is the role of the digestive system in food breakdown?

  • Enzymes produced by specialized cells
  • Different enzymes for different food molecules
  • Breakdown of food into absorbable molecules
• What is the function of the stomach in digestion?

  To pummel food and produce digestive enzymes
• What does the pancreas produce for digestion?

  Protease, amylase, and lipase enzymes
• What is the rectum's role in digestion?

  To store faeces before excretion
• What are the steps to prepare a food sample for testing?

  1. Break up food with a pestle and mortar
  2. Add distilled water and stir
  3. Filter the solution to remove solids
• What is the purpose of the Benedict's test?

  To test for reducing sugars in food
• What temperature should the water bath be set to for the Benedict's test?

  75°C
• How much Benedict's solution should be added to the test tube?

  About 10 drops
• Why are enzymes important in digestion?

  They catalyze the breakdown of food molecules into absorbable forms