the importance of consistency in experimental technique;

the necessity of producing standard curves and zeroing blanks in order to quantify data;

how the maximum rate of an enzyme can be determined;

the effect of enzyme and substrate as limiting factors; and

how and why pH and temperature affect the function of an enzyme.

3. a) List three ways to increase the probability of collisions.
    b) What is the major factor in determining whether a collision will lead to a successful
        chemical reaction?

Day One
     I.     MICROPIPETTOR EXERCISE (this is an individual activity)
     II.    DETERMINING A STANDARD CURVE (this is a group activity)

Day Two (these are all group activities)
     III.     DETERMINING THE MAXIMUM RATE OF AN ENZYMATIC REACTION
             OR HOW FAST CAN AN ENZYME WORK?
     IV.   THE EFFECT OF SUBSTRATE CONCENTRATION ON THE REACTION RATE
     V.    THE EFFECT OF ENZYME CONCENTRATION ON THE REACTION RATE
     VI. THE EFFECT OF pH ON ENZYMATIC ACTIVITY
     VII.  THE EFFECT OF TEMPERATURE ON THE REACTION RATE

• I-II.  All groups will do parts I & II on Day One, and part III on Day Two.
• VI.
• Run separate blanks for each pH value.
• The pH 3 starch solution reaction mixture will give an absorbance reading of "less than zero" as measured against its blank.  Simply treat it as a zero reading.
• VII.  See TA for help in setting this up.  (HINT:  use the 250 ml beakers for extra water baths.)

• Boiling beads should always be used (to prevent splashing as water boils).
• Color reagent contains harmful chemicals & should be used with caution.
• If spillage occurs, clean with wet paper towels.
• If skin contact occurs, wash well with soap & water.
• Hot plates should be turned off & unplugged after use, and the beakers of water should be set aside to cool.

• You must have a good graph for each part before going on to the next experiment.
• Do NOT cross-contaminate solutions!  Use a fresh pipette tip every time you go into a reagent bottle.
(If in doubt, always use a fresh tip.)
• Use 600 ml beakers as boiling water baths, and 100 ml beakers for distilled water.
• The thermometers and 250 ml beakers are used only in part VII.
• The test tubes are to be used as reaction vessels and cuvettes.
• Remember to wipe tubes dry before using in the spec 20.
• Have tubes 2/3 full for best readings (at least 1/2).

• “Substances that absorb visible light are called pigments.  Different pigments absorb light of different wavelengths, and the wavelengths that are absorbed disappear.” (page 173, Campbell, 5th Edition)
• Reflected and transmitted wavelengths have the same wavelength “going in as coming out”.

Fluorescence is when one wavelength of light “goes in” (is absorbed), but a different wavelength “comes out” (is emitted).

• Accuracy refers to the agreement of a particular value with the true value.
• Precision refers to the degree of agreement among several measurements of the same quantity.  Precision reflects the reproducibility of a given type of measurement.


Example 1 is neither accurate nor precise (large random error).
Example 2 is precise but not accurate (small random errors, large systematic error).
Example 3 is precise and accurate (small random errors, no systematic error).

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