8 terms

Chapter 8

The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of _____.
a catabolic pathway. Cellular respiration is a catabolic pathway.
Energy is observed in two basic forms: potential and kinetic. Which of the following correctly matches these forms with a source of energy?
the covalent bonds of a sugar molecule: potential energy. Bonds are a form of potential energy because the energy arises from the relative positions of the atoms that form the bond.
Which of the following statements about the combustion of glucose with oxygen to form water and carbon dioxide (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O) is correct?
The entropy of the products is greater than the entropy of the reactants. A large molecule (glucose) has been converted into several smaller molecules (water and carbon dioxide); thus, the products have more disorder (greater entropy) than the reactants.
Which of the following statements about equilibrium of chemical reactions is correct?
A reaction that is at equilibrium is not capable of doing any work. The ΔG for a reaction at equilibrium is zero, which means that there is no free energy available to do any work.
Which of the following statements about ATP (adenosine triphosphate) is correct?
The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways. Catabolic pathways provide the energy needed to make ATP from ADP and Pi. The hydrolysis of ATP to ADP + Pi releases the same amount of energy.
Enzymes are described as catalysts, which means that they
increase the rate of a reaction without being consumed by the reaction. This permits enzyme molecules to be used repeatedly.
Which of the following would be unlikely to contribute to the substrate specificity of an enzyme?
The enzyme has an allosteric regulatory site. The allosteric site is distinct from the active site, and does not affect the substrate specificity of the enzyme.
Which of the following is NOT a way in which an enzyme can speed up the reaction that it catalyzes?
The active site can provide heat from the environment that raises the energy content of the substrate. An enzyme cannot extract heat from the environment to speed a reaction. It can only lower the activation energy barrier so that more substrates have the energy to react.