Enzymes Workbook Pages IB by Mahin Acharya

Explain why it was necessary to modify the lock and key model of enzyme function.

Both substrate and active site must have same shape so the substrate can fit in there.

What might happen to an enzyme's activity if a mutation caused a change to the shape of the active site.

If the change affects the active site of the enzyme, the activity of the enzyme then would be affected. The change would cause the reaction rate to go down.

How could you distinguish between competitive and non-competitive inhibition in an isolated system?

In competitive the inhibitor just block the active site, but in non- competitive the inhibitor binds to the allosteric site and changes the shape of the enzyme resulting in the change of the shape of the active site.

Identify the two broad categories of cofactors and describe an example of each.

Prosthetic groups are enzyme partner molecules that bind tightly to an enzyme and Coenzymes are a specific type of helper or partner that are organic molecules required for enzyme function that bind loosely to an enzyme. So categories of cofactors are prosthetic groups and coenzymes.

Distinguish between competitive and non-competitive inhibition

They both inhibit the enzyme from doing its job. Competitive inhibition compete with the normal substrate for the enzyme's active site. Non- competitive inhibitors bind at another site and they inactivate the enzyme by altering its shape so the substrate doesn't fit.

explain exactly how cofactors enable an enzymes catalytic activity.

cofactors are needed for the reaction to occur it is a molecule that is involved in helping to catalyze the reaction. The cofactors are usually not proteins when they bind to the enzyme in assisting its reaction.

Explain why end product inhibition can also be called feedback inhibition.

product inhibition a form of enzyme regulation whereby products prevent product formation by binding to an allosteric site and inhibiting enzyme activity. It basically gives feedback to the enzyme on stop making products and to stop that you would need to stop the substrate flow and for that you need inhibitors.

Describe the general role of cofactors in enzyme activity.

to assist in enzyme activity.

explain how enzymes act as biological catalysts.

Enzymes are protein functioning as catalyst that speed up reactions by lowering the activation energy. A simple definition of an enzyme is that it is a biological catalyst that accelerates a chemical reaction.

Distinguish between the apoenzyme and cofactor.

The apoenzyme is protein part of enzyme and cofactor is not a protein. The cofactor is a additional chemical component.

Describe the current 'induced fit' model of enzyme action, explaining how it differs from the lock and key model.

The enzyme molds around the substrate, after the substrate binds to the active site. This puts strain on the bonds of substrate by twisting it, allowing for old bonds to be broken down and new ones to be formed.

Using examples, explain the role of enzymes in metabolic processes.

The main role of enzymes in metabolic processes is to assist in transferring electrons from one molecule to another.

Compare and contrast the effect of competitive and non- competitive inhibition in the relationship between the substrate concentration and the rate of an enzyme controlled reaction.

The non- competitive inhibitor seems more effective at doing its job rather than the competitive inhibitor. Reaction rate of Non-Competitive is slower to compared to competitive inhibition.

Explain what is meant by the active site of an enzyme and relate it to the enzyme's tertiary structure.

The part of the enzyme into which the substrate binds and undergoes reaction is the active site. These sites are small pockets on the tertiary structure where ligands bind to it using weak forces.

Explain how an allosteric regulator controls an enzyme's activity

when a molecule binds to the allosteric site it alters the enzyme's shape or conformation, which then changes how the enzyme functions.