Chapter 5 - Activation Energy and Enzymes

Where does the energy for chemical reactions on ancient Earth primarily come from?

• Fossil fuels

• Lightning, sunlight, and heat from molten rock

• Wind energy

• Coal

What is the role of adenosine triphosphate (ATP) in chemical reactions?

• It directly powers all reactions.

• It serves as an energy-carrying intermediary.

• It acts as a catalyst.

• It prevents reactions from occurring.

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NGSS.HS-LS1-7

Why does ATP act as an energy-carrying intermediary for certain chemical reactions in a cell?

• It stores energy safely in small packets, preventing excessive heat buildup that could damage the cell

• It can release energy quickly when needed, powering both endergonic and exergonic reactions

• It can be recycled, allowing for continuous energy transfer within the cell

• All of the above

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NGSS.HS-LS1-7

The energy needed by reactants for an effective collision leading to the formation of products is called the

• activation energy
• change in entropy
• change in enthalpy
• free energy

Which letter corresponds to the energy of the reactants?

• A
• B
• C
• D

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NGSS.HS-PS1-4

Which letter corresponds to the energy of the products?

• A
• B
• C
• D

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NGSS.HS-PS1-4

NGSS.HS-PS3-1

Which letter corresponds to the activation energy of this reaction?

• A
• B
• C
• D

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NGSS.HS-PS1-4

What does the activation energy (E_a) represent in a chemical reaction?

• The total energy of products

• The energy required to get reactants to the transition state

• The energy released during the reaction

• The energy lost to the environment

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NGSS.HS-PS3-1

Which of the following is true about catalysts?

• They increase the activation energy required for reactions.

• They decrease the activation energy and stabilize reactants.

• They change the products of the reaction.

• They are consumed during the reaction.

Enzymes (biological catalyst) work by lowering the _______________ for chemical reactions.

• products
• solutes
• activation energy
• reactants

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NGSS.HS-LS1-7