C + D + energy.
CHAPTER 6, METABOLISM, ENERGY AND ENZYMES QUIZ
CIRCLE THE CORRECT ANSWER
1. Which form of energy is Not correctly associated with an example?
kinetic energy. fat molecules
kinetic energy. movement of muscles
chemical energy. glucose
potential energy. water held behind a dam
potential energy. ATP
2. Which Best describes the first law of thermodynamics?
Energy is not created nor destroyed, but it can change into matter.
Energy is not created nor destroyed, but it can change from one energy form to another.
Energy can be created from matter or used to produce matter.
Some useful energy is lost as heat whenever an energy transfer occurs.
Energy transfers are always 100% efficient in changing energy from one useful form to another.
3. Which Best describes the second law of thermodynamics?
Energy is not created nor destroyed, but it can change into matter.
Energy is not created nor destroyed, but it can change from one energy form to another.
Energy can be created from matter or used to produce matter.
Some useful energy is lost as heat whenever an energy transfer occurs.
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?
When a liter of gasoline is burned in a car engine, 100% of its energy goes into moving the car along the road.
You eat a "quarter pounder" hamburger and assemble
exactly a quarter pound of additional
body weight on your body.
Eventually sunlight that is absorbed on the earth returns to space as dispersed heat.
A calorie of sunlight becomes a calorie of plant
tissue that, eaten by you, becomes a
calorie of heat lost in muscle "power".
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
coupling reactions
free energy
endergonic reactions only
exergonic reactions only
metabolism
6. Endergonic reactions
are always coupling reactions
have a negative change in free energy and occur spontaneously
can only occur if there is an input of energy
have products with less free energy than the reactants.
All of the above are correct.
7. Which of these statements is Not a consequence of the second law of thermodynamics?
While the total amount of energy is unchanged, the energy lost as heat is no longer useful to the cell in doing work.
Reactions that occur spontaneously are those that increase the amount of useful energy in a system.
The amount of disorder in the universe is always increasing.
To maintain organization of a cell, a continual input of energy is required.
8. Coupling occurs when the energy by an exergonic reaction is
used to drive another exergonic reaction.
used to drive an endergonic reaction.
lost as nonusable heat to the environment.
used to decrease the entropy of the universe.
All of the above are correct.
9. The subunits from which ATP is made are
ADP and phosphate
FAD and NAD+
FAD and NADPH
ADP and FAD
ADP and NAD+
10. ATP is considered to be
an enzyme used widely in all kinds of cells.
a molecule that carries a great deal of chemical energy in a chemical bond.
a coenzyme used to inhibit or activate different enzymes.
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
the base adenine and the sugar ribose.
the adenosine and the phosphate groups.
the adenosine diphosphate and the third phosphate.
the base adenine and the phosphate groups.
All of the above bonds release energy as ATP is completely broken down.
12. Which of the following is characteristic of enzymes?
They lower the energy of activation of a reaction by binding the substrate.
They raise the energy of activation of a reaction by binding the substrate.
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 _____.
"-ose". cell in which it is found
"-ase". cell in which it is found
"-ose". substrate
"-ase". substrate
"-ase". coenzyme
14. Which statement describes the currently accepted theory of how an enzyme and its substrate fit together?
As the product is released, the enzyme breaks down.
The enzyme is like a key that fits into the substrate, which is like a lock.
The active site is permanently changed by its interaction with the substrate.
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?
Higher temperatures generally increase the activity of an enzyme up to a point.
Above a certain range of temperatures, the protein of an enzyme is denatured.
A change in pH can cause an enzyme to be inactivated.
An enzyme's activity is generally reduced by an increase in substrate concentration.
When sufficient substrate is available, the active site will nearly always by occupied.
16. Which statement is Not true about enzyme inhibition?
In competitive inhibition, the inhibitor binds to the active site of the enzyme.
In noncompetitive inhibition, the inhibitor binds to the allosteric site of the substrate.
In irreversible inhibition, a poison binds to the enzyme so that it can never work again.
Most inhibitors act in a reversible fashion.
All of the above statements are true.
17. Which is most closely associated with negative feedback?
As you turn on a faucet, more water flows out of it.
As the sun rises, a morning glory opens its flowers.
As the temperature falls in a house, the heater comes on.
As you study biology more thoroughly, you learn more about it.
18. A coenzyme is
an ionic cofactor that interacts with an enzyme to allow it to work.
a protein cofactor that interacts with an enzyme to allow it to work.
a nonprotein organic cofactor that interacts with an enzyme to allow it to work.
an ionic cofactor that interacts with an enzyme to inhibit it.
a protein cofactor that interacts with an enzyme to inhibit it.
19. A substance that is Not a coenzyme is
ATP NAD+ NADPH FAD
20. Solar energy is stored in which molecule during photosynthesis?
FAD ATP NADPH Both B and C are correct.
21. Which organelles contain functioning ATP synthetase complexes in their membranes?
Golgi complexes and lysosomes
mitochondria and chloroplasts
endoplasmic reticulum and vesicles
vacuoles and vesicles
mitochondria and endoplasmic reticulum
22. Which term is derived from the Greek root words meaning "chemical push"?
allosteric coenzyme vitamin enzyme chemiosmosis
23. What establishes the electrochemical gradient across a membrane to provide energy for ATP production?
The chloroplast's electron transport system provides the ions.
Hydrogen ions naturally collect on the outside of the organelle membrane.
Hydrogen ions are pumped across the membrane by carrier proteins.
All of the above establish the electrochemical gradient.
24. Consider this reaction. A + B
C + D + energy.
This reaction is exergonic.
An enzyme could still speed the reaction.
ATP is not needed to make the reaction go.
A and B are reactants; C and D are products.
All of these are correct.
25. The active site of an enzyme
is similar to that of any other enzyme.
is the part of the enzyme where its substrate can fit.
can be used over and over again.
is not affected by environmental factors like pH and temperature.
Both B and C are correct.
26. If you wanted to increase the of product per unit time of an enzymatic reaction, do Not increase
the amount of substrate
the amount of enzyme
the temperature somewhat
the pH
All of these are correct.
27. An allosteric site on an enzyme is
the same as the active site.
nonprotein in nature.
where ATP attaches and gives up its energy.
often involved in feedback inhibition.
All of these are correct.
28. During photosynthesis, carbon dioxide
is oxidized to oxygen.
is reduced to glucose.
gives up water to the environment.
is a coenzyme of oxidation-reduction.
All of these are correct.
29. Electron transport systems
are found in both mitochondria and chloroplasts.
release energy as electrons are transferred.
are involved in the production of ATP.
are located in a membrane.
All of these are correct.
30. The difference between NAD+ and NADP+ is that
only NAD production requires niacin in the diet.
one is an organic molecule and the other is inorganic because it contains phosphate.
one carries electrons to the electron transport system and the other carries them to synthetic reactions.
one is involved in cellular respiration and the other is involved in photosynthesis.
Both C and D are correct.
31. Chemiosmosis is dependent upon
the diffusion of water across a differentially permeable membrane.
an outside supply of phosphate and other chemicals.
the establishment of an electrochemical hydrogen ion gradient.
the ability of ADP to join with phosphate even in the absence of a supply of energy.
All of these are correct.
32. Since energy is completely used up by a cell, the cell requires
more energy to enter it in the form of food.
True False
33. All organisms produce heat during their metabolic processes.
True False
34. All energy used to allow a cell to function can ultimately by traced
back to an origin in the external environment.
True False
35. In order to roll a rock down a hillside, you must first push it
up out of the hole in which is rest. Pushing the
rock is analogous to the energy of activation of a chemical reaction.
True False
36. In cellular metabolism, chemical reactions occur randomly in various
parts of the cell, as chemicals happen
to bump into each other.
True False
37. As energy is converted into heat and work is a cell, the energy
will either leave the cell or be stored in various chemical bonds.
True False
38. The ultimate source of nearly all the energy that is used to support
life is sunlight.
True False
39. An enzyme is a globular protein that inhibits the formation of chemical
bonds within the enzyme's substrate(s).
True False
40. The energy of activation is the energy that must be supplied so
that molecules are able to interact with each
other in a chemical reaction.
True False
41. Feedback inhibition is the process that turns off an early enzymes
in a metabolic pathway as the result of inhibitory actions of a product
of the pathway.
True False
42. ATP is produced and used continuously in all active cells.
True False
43. The energy for ATP synthesis in chemiosmotic phosphorylation comes
from the movement of hydrogen ions
across a membrane down a concentration gradient.
True False
44. The electron transport system is associated with binding of an enzyme
to its substrate.
True False
45. Vitamins are required for the action of every enzyme in a cell.
True False
46. 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?
Bringing the temperature of the experimental setup from 20 degrees C to 50 degrees C.
Adding an acidic solution to the setup.
Adding more substrate but not enzyme.
Placing the substrate and enzyme in a container with double the capacity.
Adding enzyme but not substrate.
47. A reaction that includes energy as one of its reactants is called a(n)
exergonic reaction
hydrolysis reaction
endergonic reaction
redox reaction
dehydration reaction
48. Which of the following statements about enzymes is Not True?
Competitive inhibitors act away from the active site.
Allosteric inhibitors act away from the active site.
Allosteric inhibitors can change the size of the active site.
Competitive inhibitors usually resemble the substrate.
Noncompetitive inhibitors are allosteric inhibitors.
49. In noncompetitive inhibition, the allosteric inhibitor
attaches to the active site, preventing the substrate from attaching there.
attaches to the substrate, preventing it from attaching to the active site.
changes the pH of the environment, thus preventing enzyme-substrate complex formation.
causes the substrates to polymerize, preventing individual enzyme-substrate attachment.
attaches to the enzyme at a site away from the active site, altering the shape of the enzyme.
50. All enzymes
are proteins.
lower the activation energy of reactions.
operate at the same optimum pH.
can be identified because their names end in - ase.
require a coenzyme to work effectively.
51. In an endergonic reaction, the products of a reaction contain
more energy than the reactants, and energy is released.
more energy than the reactants, and energy must be supplied.
less energy than the reactants, and energy is released.
less energy than the reactants, and energy must be supplied.
the same amount of energy than the reactants, but due to the presence of an enzyme, energy is released.
52. _____ energy is stored energy.
kinetic heated nuclear potential None of the above.
53. ____ energy is the energy of moving objects.
kinetic heated nuclear potential None of the above.
54. The energy in a system available for doing work is know as
usable energy free energy unusable energy heat total energy
55. Enzymes do what to chemical reactions?
slow them down
speed them up
break them into individual chemicals
replace certain chemicals in the reaction
None of the above.
56. Physicists have defined a formal measure of disorder, called
randomness displacement entropy disorganization None of the above.
57. The minimum amount of energy needed for a process to occur is called the
minimal energy theory process energy kinetic energy activation energy None of the above.
58. If an organism's enzymes lose their activity that are said to be
stable denatured unstable motionless All of the above.
59. Enzymes accelerate specific chemical reactions by binding to the reacting molecules, which are called
substrates catalysts enzymatic buffers molecular plastids None of the above.
60. An inhibitor that changes the overall shape and chemistry of an enzyme is known as a(n)
allosteric inhibitor
competitive inhibitor
steric inhibitor
noncompetitive inhibitor
None of the above.
61. Which of the following will least affect the effectiveness of an enzyme?
Temperature
pH
Concentration of substrate
Concentration of enzyme
Original activation energy of system