Chapter 7

According to the first law of thermodynamics, (a) energy may be changed from one form to another but is neither created nor destroyed (b) much of the work an organism does is mechanical work (c) the disorder of the universe is increasing (d) free energy is available to do cell work (e) a cell is in a state of dynamic equilibrium.

In thermodynamics, _____________ is a measure of the amount of disorder in the system. (a) bond energy (b) catabolism (c) entropy (d) enthalpy (e) work.

The ________________ energy of a system is that part of the total energy available to do cell work. (a) activation (b) bond (c) kinetic (d) free (e) heat

A reaction that requires a net input of free energy is described as (a) exergonic (b) endergonic (c) spontaneous (d) both a and c (e) both b and c.

A reaction that releases energy is described as (a) exergonic (b) endergonic (c) spontaneous (d) both a and c (e) both b and c.

A spontaneous reaction is one in which the change in free energy \((\Delta G)\) has a ___________ value. (a) positive (b) negative (c) positive or negative (d) none of these \((\Delta G\) has no measurable value).

To drive a reaction that requires an input of energy, (a) an enzyme–substrate complex must form (b) the concentration of ATP must be decreased (c) the activation energy must be increased (d) some reaction that releases energy must be coupled to it (e) some reaction that requires energy must be coupled to it

Which of the following reactions could be coupled to an endergonic reaction with \(\Delta G=+3.56 \mathrm{kJ} / \mathrm{mol} ?\) (a) \(\mathrm{A} \longrightarrow \mathrm{B}\), \(\Delta G=+6.08 \mathrm{kJ} / \mathrm{mol}\) (b) \(\mathrm{C} \longrightarrow \mathrm{D}, \Delta G=+3.56 \mathrm{kJ} / \mathrm{mol}\) (c) \(\mathrm{E} \longrightarrow \mathrm{F}, \Delta G=0 \mathrm{kJ} / \mathrm{mol}\) (d) \(\mathrm{G} \longrightarrow \mathrm{H}, \Delta \mathrm{G}=-1.22 \mathrm{k} \mathrm{J} /\) mol (e) \(\mathrm{I} \longrightarrow \mathrm{J}, \Delta G=-5.91 \mathrm{kJ} / \mathrm{mol}\).

Consider this reaction: Glucose \(+6 \mathrm{O}_{2} \longrightarrow 6 \mathrm{CO}_{2}+6 \mathrm{H}_{2} \mathrm{O}\) \((\Delta G=-2880 \mathrm{kJ} / \mathrm{mol}) .\) Which of the following statements about this reaction is not true? (a) the reaction is spontaneous in a thermodynamic sense (b) a small amount of energy (activation energy) must be supplied to start the reaction, which then proceeds with a release of energy (c) the reaction is exergonic (d) the reaction can be coupled to an endergonic reaction (e) the reaction must be coupled to an exergonic reaction.

The energy required to initiate a reaction is called (a) activation energy (b) bond energy (c) potential energy (d) free energy (e) heat energy.

A biological catalyst that affects the rate of a chemical reaction without being consumed by the reaction is a(an) (a) product (b) cofactor (c) coenzyme (d) substrate (e) enzyme.

The region of an enzyme molecule that combines with the substrate is the (a) allosteric site (b) reactant (c) active site (d) coenzyme (e) product.

Which inhibitor binds to the active site of an enzyme? (a) noncompetitive inhibitor (b) competitive inhibitor (c) irreversible inhibitor (d) allosteric regulator (e) PABA.

In the following reaction series, which enzyme(s) is/are most likely to have an allosteric site to which the end product E binds? (a) enzyme 1 (b) enzyme 2 (c) enzyme 3 (d) enzyme 4 (e) enzymes 3 and 4.