WorksheetsEnergy & Enzymes Quick Check
Total questions: 19
Worksheet time: 11mins
Which of the following is true of metabolism in its entirety in all organisms?
Metabolism uses all of an organism's resources.
Metabolism consists of all the energy transformation reactions in an organism.
Metabolism manages the increase of entropy in an organism.
Metabolism depends on an organism's adequate hydration.
Whenever energy is transformed, there is always an increase in the
free energy of the system.
free energy of the universe.
entropy of the universe.
enthalpy of the system.
Which statement about metabolic pathways is true?
Complex chemical transformations in the cell occur in a single reaction.
Every reaction requires ATP.
Each step in a metabolic pathway is regulated by a specific enzyme.
Basic reactions vary drastically from organism to organism.
Which term most precisely describes the cellular process of breaking down large molecules into smaller
ones?
anabolism
catabolism
dehydration
catalysis
Which of the following is a statement of the first law of thermodynamics?
Energy cannot be created or destroyed.
The entropy of the universe is decreasing.
Kinetic energy is stored energy that results from the specific arrangement of matter.
The entropy of the universe is constant.
Which of the following is true for all exergonic reactions?
The reaction proceeds with a net release of free energy.
A net input of energy from the surroundings is required for the reactions to proceed.
The products have more total energy than the reactants.
The reactions are rapid.
To study the actions of the enzyme catalase on hydrogen peroxide, students performed the following experiment. Catalase was extracted from potatoes by blending raw potatoes in a blender with cold distilled water. The filtrate was stored on ice. The following hydrogen peroxide solutions were made: 1 percent, 5 percent, 10 percent, and 15 percent. Filter paper disks were soaked in the catalase filtrate and dropped into beakers containing the various solutions. The activity of the enzyme was measured by the amount of time it took for the disks to float to the surface of the solution on the bubbles produced by the reaction. The following data were obtained.
Which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions?
There was more enzyme present in the more concentrated solutions.
A greater amount of heat was generated in the more concentrated solutions.
The more concentrated solutions lowered the activation energy of the reaction.
The higher substrate concentrations in the more concentrated solutions made the reaction proceed more rapidly.
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a delta G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the delta G for the new reaction?
+40 kcal/mol
0 kcal/mol
-40 kcal/mol
-20 kcal/mol
Which of the following can be used to determine the rate of enzyme-catalyzed reactions?
Rate of disappearance of the enzyme
Rate of disappearance of the substrate
Rate of disappearance of the product
Change in volume of the solution
The diagram below shows energy changes in a specific chemical reaction with and without the addition of an enzyme to the reaction.
Which of the following questions can best be answered by the diagram?
Does the addition of an enzyme reduce the activation energy required for a reaction?
Does the addition of an enzyme result in the formation of covalent bonds?
Does the addition of an enzyme produce a greater amount of products?
Does the addition of an enzyme change the pathway for the reaction?
Protein digestion in humans is primarily carried out by three enzymes. Pepsin is found in the stomach (pH2), where it aids in the breakdown of large proteins into smaller peptides, while trypsin and chymotrypsin are found in the small intestine (pH8), where they aid in the further breakdown of the proteins into amino acids and dipeptides that can be absorbed into the bloodstream. Graph 1 shows the effect of pH on the activity levels of the three enzymes.
Which of the following best predicts how the structure and function of pepsin will change as it enters the
small intestine?
Pepsin will not change in shape and will continue to break down proteins in the small intestine.
Pepsin will not change in shape but may not work due to the basic environment of the small intestine.
Pepsin will change in shape because of the basic environment of the small intestine; therefore, its enzymatic activity will decrease.
Pepsin will change in shape because of the presence of trypsin and chymotrypsin in the small intestine, both of which act as competitive inhibitors.
A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because
the hydrolysis of starch to sugar is endergonic.
the starch solution has less free energy than the sugar solution.
the activation energy barrier for this reaction cannot be readily overcome.
starch cannot be hydrolyzed in the presence of so much water.
A series of enzymes catalyze the reaction X to Y to Z to A. Product A binds to the enzyme that converts X to Y at a position away from its active site. This binding decreases the activity of the enzyme. When substance A interacts with the enzyme that converts X to Y, substance A functions as
an intermediate.
a competitive inhibitor.
an allosteric inhibitor.
the substrate.
Phosphorylation of ADP to ATP is endergonic, whereas the hydrolysis of ATP is exergonic. The two reactions are therefore said to be
substrates
kinetic
coupled
endergonic
The diagram illustrates that ATP…
Is degraded to ADP during our cells’ catabolic reactions
Stores energy to be used for cellular work
Alternates between ATP and AMP
Is released from organic molecules during anabolic processes
An exergonic reaction with a ΔG of -9 could be used to fuel an endergonic reaction with a ΔG of…
+10
+11
+7.5
Impossible to tell with the information provided
Which of the following represents the ΔG of an enzyme catalyzed reaction?
A
B
C
D
The inhibitor shown below will ??? because it is bound to (and stabilizes) the ??? form of the enzyme.
Speed up the reaction; inactive
Speed up the reaction; active
Slow down the reaction; inactive
Slow down the reaction; active
If the temperature falls below an enzyme’s optimal range, the rate of reaction will likely ??? because…
Increase, there will be more collisions between the enzyme and its substrate
Decrease, there will be fewer collisions between the enzyme and its substrate
Increase, the enzyme will be denatured
Decrease, the enzyme will be denatured
