Unit 2 (Metabolic Processes) - Chapter 3

Question 1

What is metabolism?

3.1

Answer 1

the sum of all chemical reactions in a cell or organism

Question 2

What is activiation energy?

3.1

Answer 2

The minimum amount of energy that chemical reactants must absorb to start a reaction

Question 3

What is the transition state?

3.1

Answer 3

The temporary condition in which bonds in the reactants have reached their breaking point and new bonds are forming in the products

Question 4

What is an exothermic reaction?

3.1

Answer 4

A chemical reaction in which energy is released, leaving the products with less chemical potential energy than the reactants

Question 5

What is an endothermic reaction?

3.1

Answer 5

A chemical reaction in which energy is absorbed, giving the products more chemical potential energy than the reactants

Question 6

What is Gibbs Free Energy?

3.1

Answer 6

energy that can do useful work

Question 7

What does a negative ∆G value indicate?

3.1

Answer 7

• A negative ∆G value indicates that the free energy of the products of a reaction is less than the free energy of the reactants.
• The energy released during a reaction with a negative ∆G can be used to do work in other reactions that require energy.

Question 8

What does a positive ∆G value indicate?

3.1

Answer 8

a positive ∆G value indicates that the products have more free energy than the reactants.

Question 9

What is an exergonic reaction?

3.1

Answer 9

• A chemical reaction that releases free energy
• The products have less free energy than the reactants

Question 10

What is an endergonic reaction?

3.1

Answer 10

• A chemical reaction that absorbs free energy
• The products have more free energy than the reactants

Question 11

What is energy coupling?

3.1

Answer 11

The transfer of energy from one reaction to another in order to drive the second reaction

Question 12

What is an anabolic pathway?

3.1

Answer 12

A pathway in which energy is supplied to build complex molecules from simple molecules

Question 13

What is a catabolic pathway?

3.1

Answer 13

A pathway in which energy is released and complex molecules are broken down into simple molecules

Question 14

What three parts does ATP consist of

3.2

Answer 14

• a nitrogenous base called adenine
• ribose (which adenine is linked to)
• three phosphate groups (tri-)

Question 15

What is released when ATP is broken down by hydrolysis?

3.2

Answer 15

• The hydrolysis reaction results in the breaking of the end phosphate group and the formation of two products:
• adenosine diphosphate (ADP) and an inorganic phosphate (Pi).
• In addition, an H+ ion is released into the solution.

Question 16

What is phosphorylation?

3.2

Answer 16

The transfer of a phosphate group, usually from ATP to another molecule

Question 17

What is the ATP cycle?

3.2

Answer 17

The cyclic and ongoing breakdown and re-synthesis of ATP

Question 18

Why do cells use ATP as their “currency”?

3.2

Answer 18

• Cells use ATP as an immediate source of energy because it has specific properties that are important for the biochemical reactions that allow proper cell functioning.
• ATP provides a manageable amount of energy, and couples in very similar ways to thousands of different reactions in our cells.
• This ability to couple to so many different endergonic reactions gives ATP its “universal” characteristic