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Flashcards in Enzymes Deck (13):

What are the differences exergonic and endergonic reactions?

Endergonic reactions require energy, they have a positive delta g because final free energy is greater than initial. Exergonic reactions release energy meaning it has a negative delta g.


What does activation energy do?

It's the energy required in a chemical reaction to put molecules into a transition state.


Do exergonic reactions still require activation energy?

Yes, they require a small amount of activation energy to get the reaction started.


What does an enzyme do?

An enzyme is a catalyst that speeds up a reaction.


What is an enzyme cofactor?

Factors that some enzymes require to function.


What are examples of cofactors?

Metal ions, small organic molecules that temporarily bind to the enzymes or organic molecules permanently binding to the enzymes.


What does enzymes being saturated mean?

It means that all the binding sites are occupied. At this point rate of product formation.


What are the two typed of enzyme regulation? Which type is more thermodynamically favourable?

Competitive inhibition and allosteric inhibition. Allosteric inhibition more favourable.


What is competitive inhibition?

A regulatory molecule binds to the binding sites of thee enzyme and stops it from working.


What is Allosteric inhibition?

A regulatory molecule binds to an active site and changes the shape of the enzyme. Another regulatory molecule can bind to an active site and change the shape back.


Why is allosteric inhibition more favourable?

In order to have competitive regulation the cells must be producing a higher concentration of regulatory molecules than normal molecules in order for them to fill in the enzyme. The high level of energy required for the production of this many molecules is unfavourable. For allosteric regulation you need only the amount of regulatory molecule needed to shut down the enzymes needing to be shut down.


What is cooperative allosteric inhibition?

When one molecule binds to the enzyme and changes the shape of the binding site making it easier for the next molecule to shut down the second binding site.


Can there be irreversible inhibition?

Yes, an inhibitor can bind covalently to the side of an enzyme and cause the regulation to be irreversible.