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2 Molecular biology – 2.5 Enzymes
http://www.bioknowledgy.info/ (Chris Paine)
2.5 Enzymes - the bottom line
The learning Statements
The can you statements tell you what you notes should enable you to do. They are guidance to a minimum
expectation. The deeper your understanding the easier you will find it to respond to questions and
communicate your understanding.
2.5.U1 Enzymes have an active site to which specific substrates bind.
Can you define the terms enzyme, substrate, active-site, enzyme substrate complex and product?
Giving an example to support your case can you suggest how enzymes are named?
Can you explain the concept of enzyme-substrate specificity?
2.5.U2 Enzyme catalysis involves molecular motion and the collision of substrates with the active site.
Can you explain why most enzyme catalysis occurs in water?
Can you state that in fluids all (unattached) molecules are moving randomly?
Can you explain why collisions between enzymes and substrates are necessary for catalysis and
differentiate between successful and unsuccessful collisions?
Can you explain why substrates tend to move more rapidly than enzymes?
2.5.U4 Enzymes can be denatured.
Can you state the effect of denaturation on enzyme structure and function?
2.5.U3 Temperature, pH and substrate concentration affect the rate of activity of enzymes.
Can you sketch and annotate a graph to explain the effect of temperature upon the rate of enzyme activity?
Can you sketch and annotate a graph to explain the effect of pH upon the rate of enzyme activity?
Can you sketch and annotate a graph to explain the effect of substrate concentration upon the rate of
2.5.U5 Immobilized enzymes are widely used in industry.
Can you list examples of the use of immobilised enzymes in industry?
Can you state three ways in which enzymes can be immobilised?
Can you outline the benefits of using immobilised enzymes in industry compared to enzymes that are free to
move in solution?
2.5.A1 Methods of production of lactose-free milk and its advantages.
Can you state the main source of lactase used in processing milk?
Can state the reaction catalysed by lactase?
Can you outline the production of lactose-free milk?
Can you outline four advantages of lactose-free milk against unprocessed milk?
2.5.S1 Design of experiments to test the effect of temperature, pH and substrate concentration on the
activity of enzymes. AND 2.5.S2 Experimental investigation of a factor affecting enzyme activity. (Practical
3) AND Nature of science: Experimental design - accurate, quantitative measurements in enzyme
experiments require replicates to ensure reliability. (3.2)
http://www.bioknowledgy.info/ (Chris Paine)
Using an example can you distinguish between directly and indirectly measuring the rate of an enzyme reaction
using the product produced?
Other than the appearance of the product can you state another way of measuring the rate of an enzyme
Using examples, can you distinguish between the terms accurate/precise and reliable?
Can you distinguish between a ‘control’ and ‘controlled variables’?
Can you distinguish between the terms dependent and independent variable?
Can you give a valid example of both an independent variable and a dependent variable in an enzyme
investigation? Can you use the aforementioned variables to formulate a research question?
Can you outline a method to investigate the research question, including appropriate safety, ethical and
Can you explain the importance of including replication or a suitable sample size in your investigation and how
this would likely affect predictions that could be made on the basis of the findings from the investigation?
n.b. Separately to the questions above the investigation should be carried out and written up as a lab report to
develop your skills at using the scientific method.
Allott, Andrew. Biology: Course Companion. S.l.: Oxford UP, 2014. Print.