Homework 7
Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein?
+△H, -△S, +△G
Which of the following types of reactions would decrease the entropy within a cell?
Dehydration reactions.
The mathematical expression for the change in free energy of a system is △G =△H-T△S. Which of the following is correct?
△G is the change in free energy.
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a △G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the △G for the new reaction?
-20 kcal/mol
Which of the following is an example of potential rather than kinetic energy?
A food molecule is made up of energy rich macromolecules.
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's ____.
Activation energy
How can one increase the rate of a chemical reaction?
Add a catalyst.
Which of the following is likely to lead to an increase in the concentration of ATP in a cell?
An increase in a cell's catabolic activity.
Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?
As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.
Sucrose is a disaccharide, composed of the monosaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in ____.
Breaking the bond between glucose and fructose and forming new bonds from the atoms of water.
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
Catabolism
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
Competitive inhibition
A chemical reaction that has a positive △G is correctly described as ____.
Endergonic
Which of the following is a statement of the first law of thermodynamics?
Energy cannot be created or destroyed.
What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways?
Energy coupling
Whenever energy is transformed, there is always an increase in the _______.
Entropy of the universe.
Which of the following is true of enzymes?
Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
Which of the following terms best describes the reaction shown in the figure below?
Exergonic
When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell?
It can be added to other molecules in order to activate them.
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
It is lost to the environment.
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
What is the change in free energy of a system at chemical equilibrium?
No net change.
The active site of an enzyme is the region ___.
On the enzyme that binds substrate
Using the figure below, which best describes the reaction?
The amount of free energy released as a result of the catalyzed reaction is indicated by "d."
According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?
The binding of the substrate changes the shape of the enzyme's active site.
Which of the following best describes enthalpy (H)?)
The heat content of a chemical system.
For living organisms, which of the following is an important consequence of the first law of thermodynamics?
The organism ultimately must obtain all of the necessary energy for life from its environment.
Which of the following statements is (are) true about enzyme-catalyzed reactions?
The reaction is faster than the same reaction in the absence of the enzyme.
Which of the following is true for all exergonic reactions?
The reaction proceeds with a net release of free energy.
Which of the following is true for anabolic pathways?
They consume energy to build up polymers from monomers.
In the figure below, which of the following represents the activation energy required for the enzyme-catalyzed reaction?
b.
In the figure below, which of the following represents the activation energy required for a noncatalyzed reaction?
c.
Which of the following represents the △G of the reaction shown below?
d.
Which of the following would be the same in an enzyme-catalyzed or noncatalyzed reaction shown in the figure below?
d.
In the figure below, which of the following bests describes the reaction?
negative △G, spontaneous
