Chapter 8: Mastering Biology
As ATP begins to build up in a cell, metabolism slows down. How does this happen?
ATP acts as an allosteric inhibitor to many of the enzymes involved in metabolism, thus slowing their function.
Cells use ATP constantly, but ATP is considered a renewable resource. What process makes this possible?
ATP can be regenerated by the addition of a phosphate group to ADP.
Which of the following correctly states the relationship between anabolic and catabolic pathways?
Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.
Which of the following statements correctly describes cofactors and enzymes?
Both are nonprotein enzyme helpers; but most cofactors are metal ions, and coenzymes are organic molecules that are a specific type of cofactor.
Which of the following statements is correct regarding competitive and noncompetitive enzyme inhibitors?
Competitive inhibitors bind to the active site of an enzyme while noncompetitive inhibitors bind to an enzyme away from the active site.
Which of the following statements about enzyme function is correct?
Enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output.
The primary manner in which cells manage their energy resources in order to do work is called energy coupling. Which of the following statements accurately defines energy coupling?
Exergonic reactions drive endergonic reactions.
Enzyme activity is affected by pH because
High or low pH may disrupt the hydrogen bonding or ionic interactions and thus change the shape of the active site
Which of the following statements is correct regarding kinetic and potential energy?
Kinetic energy is associated with the relative motion of objects, and potential energy is the energy that matter possesses because of its location or structure.
Which of the following statements about the active site of an enzyme is correct?
The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.
What best characterizes the role of ATP in cellular metabolism?
The free energy released by ATP hydrolysis that may be coupled to an endergonic process via the formation of a phosphorylated intermediate.
At low pH, a particular enzyme produces a large amount of product; at neutral pH and high pH, no product is produced by the enzyme. How does pH affect the function of this enzyme?
The optimal pH for this enzyme is an acidic pH; neutral pH, and above, alter ionic bonds in the enzyme, rendering it nonfunctional.
The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule is an example of ____.
allosteric regulation
An exergonic reaction ____ free energy, and an endergonic reaction ____ free energy.
releases; absorbs
