NC Bio 4.1.3 #2

Enzymes catalyze chemical reactions in the human body. Which statement best describes how enzymes work?

• They speed up chemical reactions by increasing the activation energy.

• They slow down chemical reactions by increasing the activation energy.

• They speed up chemical reactions by lowering the activation energy.

• They slow down chemical reactions by lowering the activation energy.

Enzymes are substances that catalyze chemical reactions. A change in the pH of the medium is known to decrease the activity of an enzyme.

Which statement explains how a change in pH affects the activity of an enzyme?

• It alters the shape of the enzyme.

• It alters the density of the enzyme.

• It alters the solubility of the enzyme.

• It alters the concentration of the enzyme.

• The results support the hypothesis because the highest level of enzyme action occurs at a pH above 7.

• The results support the hypothesis because both pepsin and trypsin are active at a pH of 5.

• The results do not support the hypothesis because pepsin has a reduced rate of action above a pH of 3.

• The results do not support the hypothesis because trypsin has the lowest rate of enzyme action at pH levels above 5.