Introduction to Metabolism

Which of the following is the most randomized form of energy?
1. light
2. electrical
3. thermal (heat)
4. mechanical
5. chemical potential energy
How does an enzyme catalyze a reaction?
1. By supplying the energy to speed up a reaction.
2. By lowering the energy of activation of a reaction.
3. By lowering the "delta" G of the reaction.
4. By changing the equilibrium of a spontaneous reaction.
5. By increasing the amount of free energy of a reaction.
Why is ATP an important molecule in metabolism?
1. It has high-energy phosphate bonds.
2. Its phosphate bonds are easily formed and broken.
3. Its hydrolysis is endergonic.
4. It is readily obtained from an organism's environment.
5. It is extremely stable.
The control of enzyme function is an important aspect of cell metabolism. Which of the following is LEAST likely to be a mechanism for enzyme control?
1. allosteric regulation.
2. cooperativity
3. feedback inhibition
4. removing cofactors
5. reversible inhibition
Which of the following would decrease the entropy within a system?
1. condensation reaction
2. hydrolysis
3. respiration
4. digestion
5. catabolism
What is the change in free energy at chemical equilibrium?
1. slightly increasing
2. greatly increasing
3. slightly decreasing
4. greatly decreasing
5. no net change
Which of the following is part of the first law of thermodynamics?
1. Energy cannot be created or destroyed.
2. The entropy of the universe is decreasing.
3. The entropy of the universe is constant.
4. Kinetic energy is stored energy that results from the specific arrangement of matter.
5. Energy cannot be transferred or transformed.
Whenever energy is transformed , there is always an increase
1. in the free energy of the system.
2. in the free energy of the universe.
3. in the entropy of the system.
4. in the entropy of the universe.
5. in the enthalpy of the universe.
Which of the following is TRUE of exergonic reactions?
1. The products have more free energy than the reactants?
2. The products have less free energy than the reactants.
3. Reactants will always be completely converted to products.
4. A net input of energy from the surroundings is required for the reactions to proceed.
5. The reactions upgrade the free energy in the products at the expense of energy form the surroundings.
Which term most precisely describes the general process of breaking down large molecules into smaller ones?
1. catalysis
2. metabolism
3. anabolism
4. dehydration
5. catabolism
ATP generally energizes a cellular process by
1. releasing heat upon hydrolysis.
2. acting as a catalyst.
3. direct chemical transfer of a phosphate group.
4. releasing ribose electrons to drive reactions.
5. emitting light flashes
A solution of starch at room temperature does not spontaneously decompose rapidly to a sugar solution because
1. the starch solution has less free energy than the sugar solution.
2. the hydrolysis of starch to sugar is endergonic.
3. the activation energy barrier cannot be surmounted in most of the starch molecules.
4. starch cannot be hydrolyzed in the presence of so much water.
5. starch hydrolysis is non spontaneous
What is an organic, non protein component of an enzyme molecule called
1. an accessory enzyme
2. an allosteric group
3. a coenzyme
4. a functional group
All of the following statements are representative of the second law of thermodynamics EXCEPT:
1. Energy transfers are always accompanied by some loss.
2. Heat energy represents lost energy to most systems.
3. Systems tend to rearrange themselves toward greater entropy.
4. Highly organized systems require energy for their maintenance.
5. Every time energy changes form, there is a decrease in entropy.
According to the second law of thermodynamics, all of the following are true
EXCEPT that
1. the synthesis of large molecules from small molecules is exergonic.
2. the Earth is an open system.
3. life exists at the expense of greater energy than it contains.
4. entropy increases in a closed system.
5. every chemical transformed represents a loss of free energy.
The chemical reaction that results in a positive change in "G" is correctly described as
1. endergonic
2. exergonic
3. enthalpic
4. spontaneous
5. exothermic
Which of these statements regarding enzymes is FALSE?
1. Enzymes are proteins that function as catalysts.
2. Enzymes display specificity for certain molecules to which they attach.
3. Enzymes provide activation energy for the reactions they catalyze.
4. The activity of enzymes can be regulated by factors in their immediate environment.
5. An enzyme may be used many times over for a specific reaction.
How can one increase the rate of a chemical reaction?
1. Increase the activation energy needed.
2. Cool the reactants.
3. Decrease the concentration of reactants.
4. Add a catalyst.
5. Increase the entropy of reactants.
Which of the following statements regarding enzymes is TRUE?
1. Enzymes have no effect on the rate of a reaction.
2. Enzymes increase the rate of reaction.
3. Enzymes change the direction of chemical reactions.
4. Enzymes are permanently altered by the reactions they catalyze.
5. Enzymes prevent changes in substrate concentrations from having an effect on reaction rates.
Which of the following statements is TRUE concerning catabolic pathways?
1. They combine molecules into more complex and energy-rich molecules.
2. They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.
3. They involve endergonic reactions that break complex molecules into simpler ones.
4. They are spontaneous and do not need enzyme catalysis.
5. They build up complex molecules such as protein from simpler compounds.
According to the induced fit hypothesis of enzyme function, which of the following is CORRECT?
1. The binding of the substrate depends on the shape of the active site.
2. Some enzymes become denatured when activators bind to the substrate.
3. A competitive inhibitor can outcompete the substrate for the active site.
4. The binding of the substrate changes the shape of the enzyme slightly.
5. The active site creates a microenvironment ideal for the reaction.
Correct statements regarding ATP include:

1. ATP serves as a main energy shuttle inside cells.
2. ATP drives endergonic reaction in the cell by the enzymatic transfer of the phosphate group to specific reactants.
3. The regeneration of ATP from ADP and phosphate is an endergonic reaction.
1. 1
2. 2
3. 3
4. 1 and 2 only
5. 1, 2, and 3
All of the following statements regarding enzymes are true EXCEPT:
1. Enzymes are carbohydrates that function as agents that change the rate of reaction without being consumed in the reaction.
2. Enzymes allow molecules to react in metabolism by lowering activation energies.
3. Each type of enzyme has a unique shaped active site that gives it specificity.
4. Enzymes are very sensitive to environmental conditions that influence the weak chemical bonds responsible for their three-dimensional structure.
5. Some enzymes change shape when regulator molecules, either activators or inhibitors, bind to specific allosteric receptor sites.
According to the first law of thermodynamics,
1. matter can be neither created nor destroyed.
2. energy is neither created nor destroyed.
3. all processes increase the entropy of the universe.
4. systems rich in energy are intrinsically unstable.
5. the universe loses energy becasue of friction.
Of the following choices, which is the best analogy to the metabolic pathways in cells.
1. a Ferris wheel that continuously turns in a circle, stopping only as people climb on and off the seats of the ride.
2. the organized street system of a large city where cars travel specific roads and visit gas stations for fuel.
3. two locomotive racing up a mountain while pulling several box cars.
4. ripples on the surface of a lake when a rock is tossed into the water.
5. a stampede of wild horses after a rifle is fired in the air.
The transfer of free energy from catabolic pathways to anabolic pathways is best called
1. feedback regulation
2. bioenergetics
3. energy coupling
4. entropy
5. cooperativity
In an organism, the energy available to do work is called free energy because
1. it can be obtained with no cost to the system.
2. it can be spent with no cost to the universe.
3. the organism can live free of it if necessary.
4. it is available for work.
5. it is equivalent to the system's total energy
Metabolism is best described as
1. synthesis of macromolecules
2. breakdown of macromolecules
3. control of enzyme activity.
4. all of an organism's chemical processes.
5. None of these describes metabolism
Catabolic pathways
1. do not depend on enzymes
2. consume energy to build up polymers from monomers.
3. release energy as they degrade polymers to monomers.
4. lead to the synthesis of catabolic compounds
Anabolic pathways
1. do not depend on enzymes.
2. consume energy to build up polymers from monomers.
3. release energy as they degrade polymers to monomers.
4. lead to the synthesis of catabolic compounds
Light
1. is a form of kinetic energy that can be used to do work in some cells.
2. cannot be used as a energy source by any organisms.
3. can be used as a source of energy in closed systems only.
4. energy cannot be converted to chemical energy in nature.
Evolution of biological order
1. is consistent with the second law of thermodynamics.
2. was based on organisms as closed systems.
3. violates both the first and second law of thermodynamics.
4. can be seen in individual organisms but not the ancestry of plant and animal kingdoms.
The hydrolysis of sucrose by sucrase results in
1. bringing glucose and fructose together to form sucrose.
2. the release of free water from sucrose as the bonds between glucose and fructose are broken.
3. breaking the bond between glucose and fructose and forming new bonds from water.
4. production of water from the sugar as bonds are broken between the glucose monomers.
Which of the following best describes the sequence of events in the catalytic cycle of an enzyme?
1. 1) the active site is unoccupied and substrate is available; 2) substrate enters the active site; 3) an ES complex forms; 4) substrate is converted to product; 5) product is released; 6) the active site is available for more substrate.
2. 1) the active site is unoccupied and the substrate is available; 2) substrate enters the active site; 3) substrate is converted to product; 4) product is released; 5) the active site is available for more substrate.
3. 1) the active site is unoccupied and substrate is available: 2) substrate enters the active site; 3) substrate is converted to product; 4) an ES complex forms; 5) product is released; 6) the active site is available for more substrate.
4. 1) the active site is unoccupied and substrate is available; 2) an ES complex enters teh activie site; 3) substrate is converted to product; 4) product is released; 5) the active site is available for more ES complex.