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cellular respiration

Which of these is exhibiting kinetic energy?

a space station orbiting Earth

"Conservation of energy" refers to the fact that _____.


Chemical energy is a form of _____ energy.



a catabolic pathway


the covalent bonds of a sugar molecule: potential energy




They consume energy to build up polymers from monomers.

Which of the following is a statement of the first law of thermodynamics?

energy cannot be created or destroyed


As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.

Whenever energy is transformed, there is always an increase in the

entropy of the universe

Which of the following statements is representative of the second law of thermodynamics?

Cells require a continuous input of energy to maintain their high level of organization.

Which of the following is an example of potential rather than kinetic energy?

a molecule of glucose



The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?

ΔG is the change in free energy.

A system at chemical equilibrium

can do no work

A chemical reaction that has a positive ΔG is best described as


For the hydrolysis of ATP to ADP + i, the free energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the free energy change is about -13 kcal/mol. What can we conclude about the free energy change for the formation of ATP from ADP and i under cellular conditions?

it is about +13 kcal/mol

The reaction A --> B + C + heat is released in a(n) _____ reaction.


A(n) _____ reaction occurs spontaneously.










Select the INCORRECT association.


What is energy coupling?




Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?

gamma-phosphate (the terminal phosphate)

A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases although they don't often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell's cytosol has a free calcium ion concentration of 10-7 while the concentration in the SR is 10-2, then how is the ATPase acting?

ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient.



In general, enzymes are what kinds of molecules?


Enzymes work by _____.

reducing EA

An enzyme _____.

is an organic catalyst




is unchanged

Enzymes are described as catalysts, which means that they _____.

increase the rate of a reaction without being consumed by the reaction




The compound is a competitive inhibitor.




the activation energy barrier for this reaction cannot easily be surmounted at room temperature.

Which of the following statements regarding enzymes is true?

Enzymes increase the rate of a reaction by lowering the activation energy barrier.

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the G for the new reaction?

-20 kcal/mol


cofactor necessary for enzyme activity


by changing the shape of the enzyme's active site

For the enzyme-catalyzed reaction shown in the figure, which of these treatments will cause the greatest increase in the rate of the reaction, if the initial reactant concentration is 1.0 micromolar?

doubling the enzyme concentration

Most enzyme molecules...

are occupied by substrate at high reactant concentrations.


What is malonic acid's role with respect to succinate dehydrogenase?

it is a competitive inhibitor

Consider a situation in which the enzyme is operating at optimum temperature and , and has been saturated with substrate. What is your best option for increasing the rate of the reaction?

Increase the enzyme concentration.

A(n) _____ inhibitor has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate.


A(n) _____ inhibitor binds to a site on the enzyme that is not the active site.


Usually, a(n) _____ inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity.


The competitive inhibitor competes with the substrate for the _____ on the enzyme

active site

When the noncompetitive inhibitor is bonded to the enzyme, the shape of the _____ is distorted.


Enzyme inhibitors disrupt normal interactions between an enzyme and its _____.




What can you do to speed the reaction up again?




Which of the following statements describes enzyme cooperativity?

A substrate molecule bound to an active site of one subunit promotes substrate binding to the active site of other subunits.



an allosteric inhibitor


the types of transport proteins in the membrane

What kinds of molecules pass through a cell membrane most easily

small and hydrophobic

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

It exhibits a specificity for a particular type of molecule.



Which of the following statements is correct about diffusion?


The movement of the hydrophobic gas, nitrous oxide () (laughing gas) into a cell is an example of

diffusion across the lipid bilayer







When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur?

The cell will become turgid.

A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is transferred directly into one of his veins. What will be the most probable result of this transfusion?

The patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells.



What distinguishes facilitated diffusion from simple diffusion?

Membrane proteins help move molecules across the membrane.

Which of the following transporters does not use passive transport to move molecules across a membrane?

Sodium-potassium pump

True or false? Active transport differs from passive transport in that active transport does not require an input of energy.


Which membrane protein would be used to move glucose across a membrane from a region of higher concentration to a region of lower concentration?


Lactose transport by membrane proteins occurs under conditions in which the concentration of lactose inside the cell is higher than the concentration outside the cell. What type of transport is used to move lactose into the cell?

active transport

The movement of glucose into a cell against a concentration gradient is most likely to be accomplished by which of the following?

cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis


Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy.

What is the voltage across a membrane called?

membrane potential

The sodium-potassium pump is called an electrogenic pump because it

contributes to the membrane potential.

Ions diffuse across membranes through specific ion channels

down their electrochemical gradients



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