Cellular Energetics Practice Quiz 1

Synthesis of macromoleculessynthesis of macromolecules

Breakdown of macromolecules

Control of enzyme activity

A and B only

A, B, and C

Catalysis

Metabolism

Anabolism

Dehydration

Catabolism

They do not depend on enzymes.

They consume energy to build up polymers from monomers.

They release energy as they degrade polymers to monomers.

They lead to the synthesis of catabolic compounds.

Both A and B

They do not depend on enzymes.

They are highly regulated sequences of chemical reactions.

They consume energy to build up polymers from monomers.

They release energy as they degrade polymers to monomers.

Both B and C

Anabolic pathways

Catabolic pathways

Fermentation pathways

Thermodynamic pathways

Bioenergetic pathways

Cellular respiration

Glycolysis

Fermentation

Citric acid cycle

Oxidative phosphorylation

The breakdown of glucose to carbon dioxide and water is exergonic.

The breakdown of glucose to carbon dioxide and water has a free energy change of -686 kcal/mol.

LivThe breakdown of glucose to carbon dioxide and water involves oxidation-reduction or redox reactions.

Only A and B are correct.

A, B, and C are correct.

The molecule that is reduced gains electrons.

The molecule that is oxidized loses electrons.

The molecule that is reduced loses electrons.

The molecule that is oxidized gains electrons.

Both A and B are correct.

Gains electrons and gains energy.

Loses electrons and loses energy.

Gains electrons and loses energy.

Loses electrons and gains energy.

Neither gains nor loses electrons, but gains or loses energy.

The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide.

Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O).

The oxidation of organic compounds can be used to make ATP.

The electrons have a higher potential energy when associated with water and CO2 than they do in organic compounds.

The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.

C6H12O6 is oxidized and O2 is reduced.

O2 is oxidized and H2O is reduced.

CO2 is reduced and O2 is oxidized.

C6H12O6 is reduced and CO2 is oxidized.

O2 is reduced and CO2 is oxidized.

Dehydrogenated.

Hydrogenated.

Oxidized.

Reduced.

An oxidizing agent.

NAD+ is reduced to NADH during both glycolysis and the citric acid cycle.

NAD+ has more chemical energy than NADH.

NAD+ is reduced by the action of dehydrogenases.

NAD+ can receive electrons for use in oxidative phosphorylation.

In the absence of NAD+, glycolysis cannot function.

The organic molecule or glucose must be negatively charged in order to reduce the positively charged NAD+.

Oxygen must be present to oxidize the NADH produced back to NAD+.

The free energy liberated when electrons are removed from the organic molecules must be greater than the energy required to give the electrons to NAD+.

A and B are both correct.

A, B, and C are all correct.

Mitochondrial matrix

Mitochondrial outer membrane

Mitochondrial inner membrane

Mitochondrial intermembrane space

Cytosol

Transferred to ADP, forming ATP.

Transferred directly to ATP.

Retained in the pyruvate.

Stored in the NADH produced.

Used to phosphorylate fructose to form fructose-6-phosphate.

Its hydrolysis provides an input of free energy for exergonic reactions.

It provides energy coupling between exergonic and endergonic reactions.

Its terminal phosphate group contains a strong covalent bond that when hydrolyzed releases free energy.

. A and B only

A, B and C

Has a G of about -7 kcal/mol under standard conditions.

Involves hydrolysis of a terminal phosphate bond of ATP.

Can occur spontaneously under appropriate conditions.

Only A and B are correct.

A, B, and C are correct.

Cells are open systems, but a test tube is a closed system.

Cells are less efficient at heat production than nonliving systems.

The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube.

The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes.

Cells convert some of the energy of ATP hydrolysis into other forms of energy besides heat.

Releasing heat upon hydrolysis.

Acting as a catalyst.

Coupling free energy released by ATP hydrolysis to free energy needed by other reactions.

Breaking a high-energy bond.

Binding directly to the substrate(s) of the enzyme.

Feedback regulationfeedback regulation

Bioenergetics

Energy coupling

Entropy

Cooperativity

They combine molecules into more energy-rich molecules.

They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.

They are endergonic.

They are spontaneous and do not need enzyme catalysis.

They build up complex molecules such as protein from simpler compounds.

ATP serves as a main energy shuttle inside cells.

ATP drives endergonic reactions in the cell by the enzymatic transfer of the phosphate group to specific reactants.

The regeneration of ATP from ADP and phosphate is an endergonic reaction.

A and B only

A, B, and C

The reaction is faster than the same reaction in the absence of the enzyme.

The free energy change of the reaction is the same as the reaction in the absence of the enzyme.

The reaction always goes in the direction toward chemical equilibrium.

A and B only

A, B, and C

Increase the activation energy needed.

Cool the reactants.

Decrease the concentration of the reactants.

Add a catalyst.

Increase the entropy of the reactants.