1. 2–4 Chemical Reactions and Enzymes
Photo Credit: Richard Megna/Fundamental Photographs
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Chemical Reactions
Chemical Reactions
A chemical reaction changes a set of chemicals into another form.
Anabolic- puts together
Catabolic- takes apart
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Chemical Reactions
The elements or compounds that enter are reactants.
The elements or compounds produced are products.
Reactants  (reaction happening) Products
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Energy in Reactions
Activation Energy
The energy that is needed to get a reaction started (like a spark starting a fire)
Chemical reactions that release energy often occur spontaneously. Chemical reactions that absorb energy will occur only with a source of energy. The peak of each graph represents the energy needed for the reaction to go forward. The difference between this required energy and the energy of the reactants is the activation energy.
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Enzymes
Catalysts
Chemical reactions that make life possible are slow or have high activation energy.
Catalysts – speed up reactions by lowering activation energy.
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Enzymes
Enzymes- the catalysts inside you body - - Speed up chemical reactions in cells Are recycled, don’t get used up.
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Enzyme Action
Substrates – what the enzyme works on
Active Site – where the substrate and enzyme connect like a lock and key
Enzymes can connect substrates together or take them apart
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Enzymes are Protein
They do their job because of their shape.
They only work with substrates that fit.
If they change shape they stop working
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Enzyme Action
Enzymes can be affected by any variable that influences a chemical reaction.
pH values –
too acidic or basic changes shape
Changes in temperature-
Hot changes shape, cold slows down reactions
Enzyme or substrate concentrations-
High concentration = fast, Low = slow
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2–4
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2–4
The elements or compounds produced by a chemical reaction are known as
reactants.
enzymes.
products.
waste.
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2–4
The factor that prevents many energy-releasing reactions from occurring at relatively low temperatures is called
catalytic energy.
chemical bond energy.
enzyme energy.
activation energy.
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2–4
Which of the following can affect how well an enzyme can function?
Temperature
pH Level
Concentration
All of the above
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2–4
Which of the following statements is true?
All proteins are enzymes.
All catalysts are enzymes.
All enzymes are catalysts.
All catalysts are proteins.
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2–4
Open-ended
Why is the shape of the enzyme so important to its job within your body?
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