enzymes Flashcards
what are enzymes
Enzymes are proteins that are involved in all metabolic reactions, where they function as biological catalysts.
Catalyst
Catalyst: a substance that speeds up a chemical reaction and is not changed by the reaction
why are enzymes important?
Necessary to all living organisms as they maintain reaction speeds of all metabolic reactions (all the reactions that keep an organism alive) at a rate that can sustain life
For example, if we did not produce digestive enzymes, it would take around 2 - 3 weeks to digest one meal; with enzymes, it takes around 4 hours
describe the enzyme action
1.Enzymes are specific to one particular substrate(s) as the active site of the enzyme, where the substrate attaches,is complementary shape to its substrate
2.When the substrate moves into the enzyme’s active site they become known as the enzyme-substrate complex
3.The product is made from the substrate(s) and is released
-Enzymes are specific to one particular substrate(s) as the active site of the enzyme, where the substrate attaches, is a complementary shape to the substrate
-This is because the enzyme is a protein and has a specific 3-D shape
-This is known as the lock and key hypothesis
-When the substrate moves into the enzyme’s active site they become known as the enzyme-substrate complex
-After the reaction has occurred, the products leave the enzyme’s active site as they no longer fit it and it is free to take up another substrate
When do Enzymes work the fastest?
Enzymes work fastest at their ‘optimum temperature’ – in the human body, the optimum temperature is 37⁰C
What is denaturation?
Heating to high temperatures (beyond the optimum) will break the bonds that hold the enzyme together and it will lose its shape -this is known as denaturation
What happens when enzymes are denatured?
Denaturation is irreversible - once enzymes are denatured they cannot regain their proper shape and activity will stop
Why can’t substances fit into denatured enzymes?
Substrates cannot fit into denatured enzymes as the shape of their active site has been lost
low temperatures do not denature enzymes, they just make them work more slowly. HOW?
Increasing the temperature from 0⁰C to the optimum increases the activity of enzymes as the more energy the molecules have the faster they move and the number of collisions with the substrate molecules increases, leading to a faster rate of reaction
What happenes If the pH is too high or too low of an enzyme
-If the pH is too high or too low, the bonds that hold the amino acid chain together to make up the protein can be destroyed.
-This will change the shape of the active site, so the substrate can no longer fit into it, reducing the rate of activity
What will Moving too far away from the optimum pH cause?
Moving too far away from the optimum pH will cause the enzyme to denature and activity will stop
