Enzymes

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Enzymes are proteins that function as biological catalysts. So, they are molecules that speed up a chemical reaction without being changed by the reaction.
Lock and key hypothesis
Enzymes are folded into complex 3D shapes that allow smaller molecules to fit into them. The place where these molecules fit is called the active site.
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In the lock and key hypothesis, the shape of the active site matches the shape of its substrate molecules. This makes enzymes highly specific. Each type of enzyme can usually catalyse only one type of reaction (some may catalyse a few types of reactions).
Denaturing enzymes
If enzymes are exposed to extremes of pH or high temperatures the shape of their active site may change.

If this happens then the substrate will no longer fit into the enzymes. This means the key will no longer fit the lock. We say tha
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As the temperature increases so do the rate of enzyme activity. Optimum activity is reached at the enzyme's optimum temperature. A continued increase in temperature results in a sharp decrease in activity as the enzyme's active site changes shape. It is n
Effects of pH
Changes in pH also alter the shape of an enzyme’s active site. Each enzyme work bests at a specific pH value. The optimum pH for an enzyme depends on where it normally works. For example, enzymes in the small intestine have an optimum pH of
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Substrate concentration
Enzymes will work best if there is plenty of substrate. As the concentration of the substrate increases, so does the rate of enzyme activity. However, the rate of enzyme activity does not increase forever. This is because a point w
Enzymes and food
Carbohydrates, proteins and lipids are large molecules that are needed by the body for growth, repair and metabolism. They are found in our food. These molecules are too large to pass from the intestine into the blood, so digestive enzyme
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A calorimeter is a machine used in the process of calorimetry. Small samples of material are placed in the machine which burns them. The energy given off when the material burns is measured.

Calorimeters are often used in the food industry to measure the
The simplest calorimeter can be made by arranging a beaker of water above a burning sample. The change in temperature of the water is a direct measure of the energy held within the sample.
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Other cards in this set

Card 2

Front

Denaturing enzymes
If enzymes are exposed to extremes of pH or high temperatures the shape of their active site may change.

If this happens then the substrate will no longer fit into the enzymes. This means the key will no longer fit the lock. We say tha

Back

In the lock and key hypothesis, the shape of the active site matches the shape of its substrate molecules. This makes enzymes highly specific. Each type of enzyme can usually catalyse only one type of reaction (some may catalyse a few types of reactions).

Card 3

Front

Effects of pH
Changes in pH also alter the shape of an enzyme’s active site. Each enzyme work bests at a specific pH value. The optimum pH for an enzyme depends on where it normally works. For example, enzymes in the small intestine have an optimum pH of

Back

Preview of the back of card 3

Card 4

Front

Enzymes and food
Carbohydrates, proteins and lipids are large molecules that are needed by the body for growth, repair and metabolism. They are found in our food. These molecules are too large to pass from the intestine into the blood, so digestive enzyme

Back

Preview of the back of card 4

Card 5

Front

The simplest calorimeter can be made by arranging a beaker of water above a burning sample. The change in temperature of the water is a direct measure of the energy held within the sample.

Back

Preview of the back of card 5

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