High School Biology : Understanding Enzymes

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #22 : Enzymes

Which of the following is true about enzymes?

Possible Answers:

They lower the energy of products. 

They lower the activation energy of a reaction.

They are not catalysts. 

They are lipids. 

They lower the energy of reactants.

Correct answer:

They lower the activation energy of a reaction.

Explanation:

Enzymes are all proteins, however there are some RNA molecules that have been found to catalyze reactions, but they are termed ribozymes, not enzymes. They speed up reactions by lowering the activation energy of a reaction and do not change the energy states of the reactants or products. 

Example Question #5 : Understand Enzyme Structure And Purpose

How do enzymes speed up a chemical reaction?

Possible Answers:

They increase the concentration of one or more of the reactants

They lower the activation energy of a reaction

They increase the temperature of the reaction, allowing it to occur faster

They tightly bind to the transition state, speeding up the reaction by removing transition states and leaving only products

They shift the equilibrium in favor of the products, allowing more product to be created

Correct answer:

They lower the activation energy of a reaction

Explanation:

Enzymes work by lowering the activation energy of a reaction, which can occur either by bringing reactants closer together or by destabilizing the transition state. They do not affect the equilibirum of the reaction, meaning they do not affect the amount of reactants or products. They simply increase the speed at which products can be formed by reducing the amount of energy needed to power the reaction.

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