Mastering Biology Ch. 8

Which of these is exhibiting kinetic energy?

"Conservation of energy" refers to the fact that _____.

Chemical energy is a form of _____ energy.

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

Which of these are by-products of cellular respiration?

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?

For living organisms, which of the following is an important consequence of the first law of thermodynamics?

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?

Which of the following statements is representative of the second law of thermodynamics?

Which of the following types of reactions would decrease the entropy within a cell?

Which of the following is true of metabolism in its entirety in all organisms?

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?

Which of the following statements about equilibrium of chemical reactions is correct?

The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?

Which of the following is true for all exergonic reactions?

A chemical reaction that has a positive ΔG is best described as

Which of the following best describes enthalpy (H)?

For the hydrolysis of ATP to ADP + i, the free energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the free energy change is about -13 kcal/mol. What can we conclude about the free energy change for the formation of ATP from ADP and i under cellular conditions?

Select the highest energy form of adenosine from the following images.

Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?

Which of these is ATP?

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?

When 10,000 molecules of ATP are hydrolyzed to ADP and i in a test tube, about half as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation?

Which of the following is most similar in structure to ATP?

Which of the following statements is true concerning catabolic pathways?

A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases although they don't often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell's cytosol has a free calcium ion concentration of 10-7 while the concentration in the SR is 10-2, then how is the ATPase acting?

In general, enzymes are what kinds of molecules?

Enzymes work by _____.

An enzyme _____.

What name is given to the reactants in an enzymatically catalyzed reaction?

As a result of its involvement in a reaction, an enzyme _____.

What is the correct label for "A"?

Enzymes are described as catalysts, which means that they _____.

Which of the following would be unlikely to contribute to the substrate specificity of an enzyme?

Which of the following is NOT a way in which an enzyme can speed up the reaction that it catalyzes?

The binding of a compound to an enzyme is observed to slow down or stop the rate of the reaction catalyzed by the enzyme. Increasing the substrate concentration reduces the inhibitory effects of this compound. Which of the following could account for this observation?

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's

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?

According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?

Mutations that result in single amino acid substitutions in an enzyme

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)

Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?

When you have a severe fever, what grave consequence may occur if the fever is not controlled?

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

Which curve(s) on the graphs may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot springs at temperatures of 70°C or higher?

Which temperature and pH profile curves on the graphs were most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?

Which of the following represents the ΔG of the reaction in the figure?

Which of the following terms best describes the forward reaction in the figure?

Which of the following in the figure would be the same in either an enzyme-catalyzed or a noncatalyzed reaction?

Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure?

Which of the following represents the activation energy required for a noncatalyzed reaction in the figure?

Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. Based on this information, which of the following is correct?

Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. What is malonic acid's role with respect to succinate dehydrogenase?

The Haber process is typically carried out at a temperature of approximately 500∘C. What would happen to the rate of the forward reaction if the temperature were lowered to 100∘C?

What would happen to the rate of the forward reaction if the concentration of nitrogen were decreased?

Which of the following would increase the rate of the reverse reaction?

What will happen to the rates of the forward and reverse reactions when a catalyst is added?

Complete this vocabulary exercise relating to the three types of enzyme inhibitors.

You have added an irreversible inhibitor to a sample of enzyme and substrate. At this point, the reaction has stopped completely. What can you do to regain the activity of the enzyme?

You have an enzymatic reaction proceeding at the optimum pH and optimum temperature. You add a competitive inhibitor to the reaction and notice that the reaction slows down. What can you do to speed the reaction up again?

Look at the graph of reaction rate versus substrate concentration for an enzyme. (Figure 1) In which region does the reaction rate remain constant?

In which region is the enzyme saturated with substrate?

Consider a situation in which the enzyme is operating at optimum temperature and pH, and has been saturated with substrate. What is your best option for increasing the rate of the reaction?

Rank these by reaction rate, as measured by the rate of product formation per unit time, from lowest reaction rate to highest reaction rate. To rank items as equivalent, overlap them.

Complete this vocabulary exercise relating to enzymes. Match the words in the left-hand column to the appropriate blank in the sentences in the right-hand column.

Allosteric enzyme regulation is usually associated with

Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?

An important group of peripheral membrane proteins are enzymes such as the phospholipases that cleave the head groups of phospholipids. What properties must these enzymes exhibit?

Which of the following is an example of cooperativity?

How do cells use the ATP cycle shown in the figure?

A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. With respect to the enzyme that converts X to Y, substance A functions as

Which of the following statements is most likely to be true in the case of the feedback-regulated enzymatic pathway shown?

What is the free energy change (ΔG) of the hydrolysis of ATP to ADP?

Which of the following statements about the role of ATP in cell metabolism is true?

How does an enzyme increase the rate of the chemical reaction it catalyzes?

Which statement about the binding of enzymes and substrates is correct?