Year 8 Biology

• What is diffusion?

  The movement of substances from an area of high concentration to low concentration
• Why does diffusion occur in liquids and gases?

  Because their particles move randomly from place to place
• Why is diffusion important for living things?

  It is how substances move in and out of cells
• In leaves, what gas diffuses into a leaf for photosynthesis?

  CO2
• What is the meaning of the keyword "active site"?

  Area of an enzyme where a substrate attaches
• What is the meaning of the keyword "diffusion"?

  Movement of particles from an area of high concentration to low concentration
• What is aerobic respiration?

  Respiration using oxygen and glucose to release energy
• What are enzymes?

  Protein molecules that speed up chemical reactions without being used up
• What is anaerobic respiration?

  Respiration in the absence of oxygen to release energy
• What is fermentation?

  Anaerobic respiration in some microorganisms and yeast
• What does concentration refer to?

  The amount of particles in a volume of substance
• What does "optimum" mean in the context of enzymes?

  When a condition such as pH or temperature is most suitable for enzyme activity
• What are catalysts?

  Chemical substances that speed up reactions
• What is a substrate?

  A substance that an enzyme reacts with
• What does it mean when an enzyme is denatured?

  The process where an enzyme loses its active site
• What is respiration in the context of living cells?

  A chemical reaction which takes place in living cells to release energy from glucose
• What are the two main functions of enzymes?

  • Break down larger molecules into smaller ones
  • Build larger molecules out of smaller ones
• What is the Lock and Key Theory in relation to enzymes?

  • Substrates fit specifically into the active site of an enzyme
  • Only one specific type of molecule fits into each enzyme's active site
• How do enzymes behave after a reaction?

  • The products are released
  • The enzyme remains unchanged and can be used again
• What conditions do enzymes work best in?

  • Specific temperatures
  • Specific pH conditions
• What is the naming convention for enzymes?

  • The names of enzymes all end with 'ase'
• What role do enzymes play in the digestive system?

  • Break down food into molecules small enough to diffuse into the bloodstream
• What are the specific enzymes for starch, protein, and lipids?

  • Amylase: Starch to Glucose
  • Protease: Protein to Amino acids
  • Lipase: Lipids to Glycerol + fatty acids
• What happens to enzymes outside their optimum conditions?

  • They become denatured
• How does the specificity of enzymes relate to their active sites?

  • Each enzyme has a unique active site that only fits a specific substrate