Coupling occurs when the energy released by an exergonic reaction is:
A. used to drive another exergonic reaction.
B. used to drive an endergonic reaction.
C. lost as nonusable heat to the environment.
D. used to decrease the entropy of the universe.
E. All of the choices are correct.
Identify the graph that depicts the reaction C→D.
An automobile engine is about 20 - 30% efficient in converting chemical energy to mechanical energy. Cells are about 39% efficient if the transformation of glucose to ATP. The rest of the energy is lost as heat. This is illustrative of the:
A. First Law of Thermodynamics.
B. Second Law of Thermodynamics.
C. Third Law of Thermodynamics.
D. The Cell Theory.
If a change in pH alters an allosteric site where an inhibitor binds, but doesn't change the active site for the intended substrate, it would be possible for an enzymatically controlled reaction to occur as normal.
The metabolic pathway at right involves how many possible chemical reactions?
C. a nonprotein organic cofactor that interacts with an enzyme to allow it to work.
B. Mitochondria and chloroplasts.
D. As the substrate binds to the enzyme, the shape of the active site changes to accommodate the reaction.
5 True/False Questions
Which best describes the first law of thermodynamics?
A. Energy is changed from one form to another with a loss of usable energy.
B. Energy is not created nor destroyed, but it can change from one energy form to another.
C. Energy can be created from matter or used to produce matter.
D. Some useful energy is lost as heat whenever an energy transfer occurs.
E. Energy transfers are always 100% efficient in changing energy from one useful form to another. → B. Energy is not created nor destroyed, but it can change from one energy form to another.
Of the following, which process will not denature a protein?
A. heating to temperatures above 100 C
B. addition of strong acids or strong bases
D. addition of distilled water → C. a muscle contracting
Feedback inhibition is the process that turns off an early enzyme in a metabolic pathway as the result of inhibitory actions of a product of the pathway.
True False → True
ATP is considered a high-energy compound because under cellular conditions, 7.3 kcal per mole of energy is released when a bond is broken between:
A. the base adenine and the sugar ribose.
B. the adenosine and the phosphate groups.
C. the base adenine and the phosphate groups.
D. the adenosine diphosphate and the third phosphate.
E. All of the bonds release energy as ATP is completely broken down. → D. the adenosine diphosphate and the third phosphate.
Which of the following is consistent with the laws of physics governing energy?
A. When a liter of gasoline is burned in a car engine, 100% of its energy goes into moving the car along the road.
B. You eat a "quarter-pounder" hamburger and assemble exactly a quarter-pound of additional body weight on your body.
C. Eventually sunlight that is absorbed on the earth returns to space as dispersed heat.
D. A calorie of sunlight becomes a calorie of plant tissue that, eaten by you, becomes a calorie of heat lost in muscle "power."
E. Chemical bonds are a case of converting energy to matter; breaking the bonds converts matter to energy. → C. a muscle contracting