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OCR A Biology > Enzymes > Flashcards

Flashcards in Enzymes Deck (16)
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What is an enzyme?

An enzyme is a biological catalyst that speeds up chemical reactions


What is the difference between intracellular and extracellular

Intra - inside the cell
Extra - outside the cell


How does an enzyme work?

Substrates bind to enzymes active site creating an enzyme substrate complex


How do enzymes speed up the rate of reactions?

Enzymes reduce the amount of activation energy required for a reaction to take place


What is the lock and key model?

The substrates have to have a complementary shape to bond with the enzyme


What is an induced fit model?

When substrates bond to an active site their shape changes slightly


What are the factors affecting enzyme activity?

Enzyme concentration
Substrate concentration


Why does an increasing temperature increase enzyme activity and what happens after a certain temperature?

It increases kinetic energy which means molecules move faster increasing the probability of a collision
After a certain temperature the enzyme's tertiary structure changes meaning its active site changes, the enzyme has denauted


How does PH affect enzyme activity?

All enzymes have a PH optimum tempature


How does enzyme concentration affect enzyme activity?

The more enzyme molecules there are the greater probability of a collision therefore a faster rate of reaction


How does substrate concentration affect enzyme activity?

The higher the substrate concentration the faster the reaction


What is a inorganic cofactor? and what is its basic function?

These are inorganic molecules or ions.
They help by binding with the substrate to fit the active site


What is an organic cofactor (coenzyme)? and what is its basic function?

Organic molecules
They often act as carriers moving chemical groups between different enzymes


What is a prosthetic group?

When a cofactor is tightly bound to the enzyme


What is a competitive inhibitor and how does it work?

They have a similar complementary shape to the substrate. They binds to the enzyme blocking the active site for substrates


What is a noncompetitive inhibitor and how does it work?

They bind away from the active site to an allosteric site. This causes the enzyme's active site to change meaning substates no longer have a complementary shape