Globular proteins with a specific tertiary structure, which catalyse metabolic reactions in living organisms.
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What are intracellular enzymes?Give an example.
They're inside of cells e.g. catalase and ATP synthase.
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What are extracellular enzymes?Give an example.
Outside of cells but inside of body, e.g. amylase and trypsin.
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Describe the lock and key theory.
1)Shape of enzymes and substrates are complementary.2)Have complementary charges so are attracted to each other, when enzyme and substrate bind, enzyme-substrate complex forms.3)Enzyme-product complex is produced.4)Products are released.
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What do we need in order for the enzyme and substrate to bind?
1)Activation energy needs to be met.2)Need successful collisons.
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Why are the products released?
Because the products and enzyme are no longer complementary.
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Describe the induced fit theory.
1)Active site and substrate are complementary, like a hand and glove-the glove changes shape.2)Bonds are easier to break because when the substrate and enzyme join pressure is put on the bond.
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Explain the term biological catalyst.
Something that speeds up chemical reactions without affecting the results of the reaction and without being used up.Lowers activation energy.
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Suggest how you would measure the rate of a reaction.
1)Measure rate at which reactants are used or products are formed.
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When an enzyme is at its optimum PH/Temperature, what does this mean?
It is when the enzyme works its best.
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What circumstances does an enzyme denature and what happens to it?
1)When the temperature/PH is too high.2)Its active site has changed shape- it is irreversible.
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What is a limiting factor?
Something that slows the rate of the reaction and stops the rate increasing.
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When there is a limiting factor, how can the substrate concentration be increased?
More enzymes can be added.
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What are inhibitors?
Any substance or molecule that slows down the rate of an enzyme controlled reaction by affecting the enzyme molecule.
Describe how competitive inhibitors effect rate of reaction.
1)Rate decreases.2)Inhibitor and substrate have similar shape/structure.3)Both fit into active site as they're complementary.4)Substrate molecule is blocked from entering active site.5)Fewer enzyme-substrate complexes form.
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Describe how non-competitive inhibitors effect rate of reaction.
1)Rate decreases.2)Fits into allosteric site.3)Active site changes.4)Substrate no longer complementary to active site.5)Enzyme-substrate complex doesn't form.
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What is a cofactor?
Any substance that must be present to ensure enzyme controlled reactions take place at the appropriate rate.They're part of an enzymes prosthetic group.
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What may cofactors be?
1)Charged metal ions (activators) that temporarily bind to active site.2)Organic molecules, usually vitamins or coenzymes made from vitamins.Temporarily bind with enzyme-substrate complex.
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Are chloride ions an activator or coenzyme? Describe its role.
Activator. Amylase enzymes must contain Cl- to adopt their functional shape, allowing enzyme to hydrolyse amylose to maltose.
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Are calcium ions an activator or coenzyme?Describe its role.
Activator.Thrombin enzymes responsible for blood clotting.Enzyme needs Ca2+ to form effective clot.
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Is Coenzyme A an activator or coenzyme?Describe its role.
In respiration, substrate pyruvate is broken down to acetyl, which is very reactive. Coenzyme A helps remove it from active site in a stable manner.
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Other cards in this set
Card 2
Front
What are intracellular enzymes?Give an example.
Back
They're inside of cells e.g. catalase and ATP synthase.
Card 3
Front
What are extracellular enzymes?Give an example.
Back
Card 4
Front
Describe the lock and key theory.
Back
Card 5
Front
What do we need in order for the enzyme and substrate to bind?
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