CHAPTER 8, METABOLISM, ENERGY AND ENZYMES QUIZ
NAME:____________________________________________________
_____1. Which form of energy is Not correctly associated with an example?
a) kinetic energy : fat molecules
b) kinetic energy : movement of muscles
c) chemical energy : glucose
d) potential energy : water held behind a dam
e) potential energy : ATP
_____2. Which Best describes the first law of thermodynamics?
a) Energy is not created nor destroyed, but it can change into matter.
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.
_____3. Which Best describes the second law of thermodynamics?
a) Energy is not created nor destroyed, but it can change into matter.
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.
_____4. 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 bonds converts matter to energy.
_____5. All of the biochemical pathways in a cell constitute
a) coupling reactions
b) free energy
c) endergonic reactions only
d) exergonic reactions only
e) metabolism
_____6. Endergonic reactions
a) are always coupling reactions
b) have a negative change in free energy and occur spontaneously
c) can only occur if there is an input of energy
d) have products with less free energy than the reactants.
e) All of the above are correct.
_____7. Which of these statements is Not a consequence of the second law of thermodynamics?
a) While the total amount of energy is unchanged, the energy lost as heat is no longer useful to the cell in doing work.
b) Reactions that occur spontaneously are those that increase the amount of useful energy in a system.
c) The amount of disorder in the universe is always increasing.
d) To maintain organization of a cell, a continual input of energy is required.
_____8. Coupling occurs when the energy 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 above are correct.
_____9. The subunits from which ATP is made are
a) ADP and phosphate
b) FAD and NAD+
c) FAD and NADPH
d) ADP and FAD
e) ADP and NAD+
_____10. ATP is considered to be
a) an enzyme used widely in all kinds of cells.
b) a molecule that carries a great deal of chemical energy in a chemical bond.
c) a coenzyme used to inhibit or activate different enzymes.
d) the precursor of a high energy membrane bounded protein.
_____11. 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 adenosine diphosphate and the third phosphate.
d) the base adenine and the phosphate groups.
e) All of the above bonds release energy as ATP is completely broken down.
_____12. Which of the following is characteristic of enzymes?
a) They lower the energy of activation of a reaction by binding the substrate.
b) They raise the energy of activation of a reaction by binding the substrate.
c) They lower the amount of energy present in the substrate.
_____13. An enzyme is generally named by adding ____ to the end of the name of the _____.
a) "-ose". cell in which it is found
b) "-ase". cell in which it is found
c) "-ose". substrate
d) "-ase". substrate
e) "-ase". coenzyme
_____14. Which statement describes the currently accepted theory of how an enzyme and its substrate fit together?
a) As the product is released, the enzyme breaks down.
b) The enzyme is like a key that fits into the substrate, which is like a lock.
c) The active site is permanently changed by its interaction with the substrate.
d) As the substrate binds to the enzyme, the shape of the enzyme site changes to accommodate the reaction.
_____15. Which statement is Not true about the effects of various conditions on the activity of an enzyme?
a) Higher temperatures generally increase the activity of an enzyme up to a point.
b) Above a certain range of temperatures, the protein of an enzyme is denatured.
c) A change in pH can cause an enzyme to be inactivated.
d) An enzyme's activity is generally reduced by an increase in substrate concentration.
e) When sufficient substrate is available, the active site will nearly always by occupied.
_____16. Which statement is Not true about enzyme inhibition?
a) In competitive inhibition, the inhibitor binds to the active site of the enzyme.
b) In noncompetitive inhibition, the inhibitor binds to the allosteric site of the substrate.
c) In irreversible inhibition, a poison binds to the enzyme so that it can never work again.
d) Most inhibitors act in a reversible fashion.
e) All of the above statements are true.
_____17. Which is most closely associated with negative feedback?
a) As you turn on a faucet, more water flows out of it.
b) As the sun rises, a morning glory opens its flowers.
c) As the temperature falls in a house, the heater comes on.
d) As you study biology more thoroughly, you learn more about it.
_____18. A coenzyme is
a) an ionic cofactor that interacts with an enzyme to allow it to work.
b) a protein cofactor that interacts with an enzyme to allow it to work.
c) a nonprotein organic cofactor that interacts with an enzyme to allow it to work.
d) an ionic cofactor that interacts with an enzyme to inhibit it.
e) a protein cofactor that interacts with an enzyme to inhibit it.
_____19. Solar energy is stored in which molecule during photosynthesis?
a) FAD b) ATP c) NADPH d) Both B and C are correct.
_____20. Which organelles contain functioning ATP synthetase complexes in their membranes?
a) Golgi complexes and lysosomes
b) mitochondria and chloroplasts
c) endoplasmic reticulum and vesicles
d) vacuoles and vesicles
e) mitochondria and endoplasmic reticulum
_____21. Consider this reaction. A + B
C + D + energy.
a) This reaction is exergonic.
b) An enzyme could still speed the reaction.
c) ATP is not needed to make the reaction go.
d) A and B are reactants; C and D are products.
e) All of these are correct.
_____22. The active site of an enzyme
a) is similar to that of any other enzyme.
b) is the part of the enzyme where its substrate can fit.
c) can be used over and over again.
d) is not affected by environmental factors like pH and temperature.
e) Both B and C are correct.
_____23. If you wanted to increase the of product per unit time of an enzymatic reaction, do Not increase
a) the amount of substrate
b) the amount of enzyme
c) the temperature somewhat
d) the pH
e) All of these are correct.
_____24. An allosteric site on an enzyme is
a) the same as the active site.
b) nonprotein in nature.
c) where ATP attaches and gives up its energy.
d) often involved in feedback inhibition.
e) All of these are correct.
_____25. A student conducts an experiment to test the efficiency of a certain enzyme. Which of the
following protocols would probably Not result in a change in the enzyme's efficiency?
a) Bringing the temperature of the experimental setup from 20 degrees C to 50 degrees C.
b) Adding an acidic solution to the setup.
c) Adding more substrate but not enzyme.
d) Placing the substrate and enzyme in a container with double the capacity.
e) Adding enzyme but not substrate.
_____26. A reaction that includes energy as one of its reactants is called a(n)
a) exergonic reaction b) hydrolysis reaction c) endergonic reaction d) redox reaction e) dehydration reaction
_____27. Which of the following statements about enzymes is Not True?
a) Competitive inhibitors act away from the active site.
b) Allosteric inhibitors act away from the active site.
c) Allosteric inhibitors can change the size of the active site.
d) Competitive inhibitors usually resemble the substrate.
e) Noncompetitive inhibitors are allosteric inhibitors.
_____28. In noncompetitive inhibition, the allosteric inhibitor
a) attaches to the active site, preventing the substrate from attaching there.
b) attaches to the substrate, preventing it from attaching to the active site.
c) changes the pH of the environment, thus preventing enzyme-substrate complex formation.
d) causes the substrates to polymerize, preventing individual enzyme-substrate attachment.
e) attaches to the enzyme at a site away from the active site, altering the shape of the enzyme.
_____29. Which of the following statements is Not True about all enzymes?
a) are proteins.
b) lower the activation energy of reactions.
c) operate at the same optimum pH.
d) can be identified because their names end in - ase.
e) require a coenzyme to work effectively.
_____30. In an endergonic reaction, the products of a reaction contain
a) more energy than the reactants, and energy is released.
b) more energy than the reactants, and energy must be supplied.
c) less energy than the reactants, and energy is released.
d) less energy than the reactants, and energy must be supplied.
e) the same amount of energy than the reactants, but due to the presence of an enzyme, energy is released.
_____31. _____ energy is stored energy.
a) kinetic b) heated c) nuclear d) potential
e) None of the above.
_____32. ____ energy is the energy of moving objects.
a) kinetic b) heated c) nuclear d) potential e) None of the above.
_____33. The energy in a system available for doing work is known as
a) usable energy b) free energy c) unusable energy d) heat e) total energy
_____34. Enzymes do what to chemical reactions?
a) slow them down
b) speed them up
c) break them into individual chemicals
d) replace certain chemicals in the reaction
e) None of the above.
_____35. Physicists have defined a formal measure of disorder, called
a) randomness b) displacement c) entropy d) disorganization e) None of the above.
_____36. The minimum amount of energy needed for a process to occur is called the
a) minimal energy theory b) process energy c) kinetic energy d) activation energy e) None of the above.
_____37. If an organism's enzymes lose their activity, they are said to be
a) stable b) denatured c) unstable d) motionless e) All of the above.
_____38. Enzymes accelerate specific chemical reactions by binding to the reacting molecules, which are called
a) substrates b) catalysts c) enzymatic buffers d) molecular plastids e) None of the above.
_____39. An inhibitor that changes the overall shape and chemistry of an enzyme is known as a(n)
a) allosteric inhibitor b) competitive inhibitor c) steric inhibitor d) noncompetitive inhibitor e) None of the above.
_____40. Which of the following will least affect the effectiveness of an enzyme?
a) Temperature b) pH c) Concentration of substrate d) Concentration of enzyme e) Original activation energy of system