Proteins and Enzymes

• What is the general shape of the primary level?

  Straight line
• What is the general shape of the secondary level?

  Alpha-helix and beta-pleated
• Where are thermophilic bacteria found?

  Archaebacteria
• At what pH do most enzymes work best at?

  Neutral (7)
• What is the optimal temperature for most enzymes?

  37 degrees C
• What is the general shape of the tertiary level?

  A single chain folded upon itself through R-group bonds, forming a unique 3D shape
• What is the general shape of the quaternary level?

  Two or more polypeptide chains bonded and folded together through R-group bonds, forming a unique 3D shape
• What is the function of enzymes?

  To catalyze (speed up) reactions
• What three letters do almost all enzymes end in?

  -ase
• What does sucrase break down?

  Sucrose
• What do proteases break down?

  Proteins
• What do lipases break down?

  Lipids
• What does DNA polymerase do?

  Build up DNA
• What does enzyme + substrate (E+S) lead to?

  enzyme-substrate complex
• What does enzyme-substrate complex lead to?

  enzyme + product
• What phrase describes how fast an enzyme is working?

  Rate of reaction
• What is the definition of rate of reaction?

  Amount of substrate changed (or amount product formed) in a given period of time.
• What is the effect of heat on enzyme activity?

  If you heat the protein above its optimal temperature, bonds break and the protein loses its secondary and tertiary structure
• What happens if the temperature is lowered?

  The enzyme can't regain its correct shape
• What happens when a protein is denatured?

  The active site changes shape so the substrate no longer fits
• Enzymes are?

  Reused and recycled
• How do enzymes speed up the reaction?

  By lowering activation energy.
• What does a competitive inhibitor do to the reaction rate?

  Slows the reaction rate
• What is this a graph of?

  Temperature

  A)

  
• Where is pepsin found?

  Stomach
• Where is Trypsin found?

  Small intestine
• What is the optimal pH for pepsin?

  pH 2
• What is the optimal pH for trypsin?

  pH 8-9
• Limiting Factor

  Substance that is in short supply, therefore limiting the reaction rate
• What does [] mean?

  Concentration
• pH of 1 to 7 are known as?

  Acids
• pH of 8 to 14?

  Bases
• As you go from 1 to <7, the acid gets weaker
• As you go from >7 to 14, the base gets stronger
• At what temperature do enzymes denature?

  40°C (104°F)
• What is the peak temperature for thermophilic enzymes?

  60 to 80°C
• Kinetic energy


  The energy of motion at low temperatures
• Molecules have low kinetic energy, so they do not move as quickly and the reaction rate is low.
• What does thermophilic mean?

  To like heat
• In acids, [H] is greater than [OH].