3. Energy &amp; Cell Processes

Which of the following are examples of the functions of enzymes?

a) A lactase enzyme breaking down lactose sugar in the small intestine.

b) A DNA polymerase enzyme synthesizing new strands of DNA.

c) A lipase enzyme breaking down fats (lipids) in the small intestine.

d) A helicase enzyme unraveling DNA so it can be replicated.

e) All of the above.

2171

rank

Which characteristics are likely associated with an enzyme isolated from a human stomach where conditions are strongly acidic.

a) An enzyme that functions properly at 70 degrees Fahrenheit and at a neutral pH.

b) An enzyme that functions properly at 98 degrees Fahrenheit and at an acidic pH.

c) An enzyme that functions properly at 98 degrees Fahrenheit and at a neutral pH.

d) An enzyme that functions properly at 70 degrees Fahrenheit and at an acidic pH.

1709

rank

Which of the following is changed by the presence of an enzyme in a reaction? and

451

Which of the following statements about enzymes is/are true?

1160

Which of the following statements about enzyme function is correct?

Which of the following statements about enzymes is incorrect?

Which of the following statements about the active site of an enzyme is correct?

Which of the following statements correctly describe(s) the role or roles of heat in biological reactions?

Which of the following environments or actions would not affect the rate of an enzyme reaction?

Enzyme activity is affected by pH because __________.

990

Add labels to the figure that follows, which illustrates the breakdown of a disaccharide inside a cell.

276

How does pH affect enzyme-catalyzed reactions? a. Protons serve as substrates for most reactions. b. Energy stored in protons is used to drive endergonic reactions. c. Proton concentration increases the kinetic energy of the reactants, enabling them to reach their transition state. d. The concentration of protons affects an enzyme's folded structure and reactivity.

592

Which of the following is a false statement regarding enzymes? a. Enzymes are proteins that speed up metabolic reactions; b. Enzymes have specific substrates; c. Enzymes supply ATP to their substrates; d. An enzyme may be used many times.

1227

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to a. add more of the enzyme. b. heat the solution to 90°C. c. add more substrate. d. add a noncompetitive inhibitor.

965

Some bacteria are metabolically active in hot springs because a. they are able to maintain a lower internal temperature. b. high temperatures make catalysis unnecessary. c. their enzymes have high optimal temperatures. d. their enzymes are completely insensitive to temperature.

1465

Enzymes usually function best at an optimal pH and temperature. The following graph shows the effectiveness of two enzymes at various temperatures. (c) From what you know about enzyme structure, explain why the rate of the reaction catalyzed by enzyme A slows down at temperatures above 40°C (140°F).

475

Enzymes usually function best at an optimal pH and temperature. The following graph shows the effectiveness of two enzymes at various temperatures. (b) One of these enzymes is found in humans and the other in thermophilic (heat-loving) bacteria. Which enzyme would you predict comes from which organism?

624

Enzymes usually function best at an optimal pH and temperature. The following graph shows the effectiveness of two enzymes at various temperatures. (a) At which temperature does enzyme A perform best? Enzyme B?

386