Factors affecting enzymes

• What is the induced fit model of enzyme action?

  Enzyme changes shape to fit substrate
• What is the lock and key model of enzyme action?

  Substrate fits exactly into active site
• What is a conformational change?

  A slight shape change in a protein
• What bonds form in the secondary structure of a protein?

  Hydrogen bonds between carboxyl and amine groups
• How does glycogen differ from amylose in structure?

  Glycogen is branched; amylose is coiled
• How would you determine the concentration of maltose using a colorimeter?

  Measure absorbance and compare to standards
• How does a change in amino acid sequence affect enzyme function?

  It alters interactions and protein shape
• What happens to enzyme activity at low temperatures?

  Low kinetic energy leads to slow reactions
• What is the effect of optimum temperature on enzyme activity?

  High kinetic energy leads to high reaction rate
• What occurs at high temperatures affecting enzyme activity?

  Heat denatures the enzyme's active site
• How does pH affect enzyme activity?

  Extreme pH denatures the enzyme's active site
• What happens to enzyme activity at low substrate concentrations?

  Low substrate limits successful collisions
• What occurs at high substrate concentrations?

  Rate plateaus as all active sites are occupied
• How do you measure the initial rate of a reaction?

  Find the slope of the tangent at time zero
• What is a tangent in the context of a curve?

  A straight line touching a point on a curve
• How do you calculate the rate from a tangent?

  Change in Y divided by change in X
• What is uncertainty in measurements?

  Amount of error in measurements
• How do you estimate uncertainty with a ruler?

  Half the smallest division on the scale
• How do you calculate percentage error?

  Percentage error = (uncertainty ÷ measurement) x 100
• What is the uncertainty for a large measuring cylinder with 2 cm³ divisions?

  ± 1 cm³
• What is the uncertainty for a digital stopwatch measuring to the nearest hundredth of a second?

  ± 0.005 seconds
• What is the uncertainty for a thermometer with 0.1 °C divisions?

  ± 0.05 °C
• How do you calculate the percentage error for 50 cm³ of oxygen produced?

  Percentage error = (0.05 ÷ 50) x 100
• What is the percentage error for 10 cm³ of oxygen produced in 5.245 seconds?

  Percentage error = 0.0095% or 0.01%