Enzymes

  • Created by: An Di
  • Created on: 23-09-19 12:14

Anabolic & Catabolic

Anabolic - Reactions of metabolism that construct molecules from smaller units. These reactions require energy in the form of ATP. e.g. photosynthesis.

CatabolicThe reactions of metabolism that break down larger molecules into smaller molecules. These reactions release energy.e.g. respiration.

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Enzyme Action

+Each enzymes active site is specific to the reaction that it catalyses. They are specific in terms of size, shape and chemical make up.

+As enzymes are made of amino acids, the order of the amino acids determine the shapes of the active site.

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Lock and Key Theory

+Suggests a specific substrate will fit into the active site of an enzyme.

+There is no change to the shape of the active site when the substrate binds.

+There is a strain on the bonds in the substrate and that causes a change to the substrate and the reaction takes place.  

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Induced Fit Model

+More accepted model - enzymes are not rigid structures.

+Enzymes can change shape slightly when it binds to the substrate to result in a tighter fit. The fit is induced.

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Extracellular Enzymes

+Enzymes that are secreted outside of the cell.

+Digestive enzymes are an example of extracellular enzymes.

+They are produced by specialised goblet cells but act on food by the gut.

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Intracellular Enzymes

+Function within the cell.

+They don't leave the cell and are found in the cytoplasm, chloroplast, mitochondria, nucleus, etc.

+They are retained inside the cell for internal use

+DNA polymerase is an example of an intracellular enzyme.
Organelles such as chloroplast and mitochondria need a lot of enzymes.

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Extracellular & Intracellular Enzymes

+Both enzymes are made inside the cell but intracellular enzymes remain in the cell.

+Extracellular enzymes are produced in the cell but work outside the cell. Quite often digestive enzymes.

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