M2

Question 1

If 14C-labeled uridine triphosphate is added to the growth medium of cells, what macromolecules will be labeled?

Answer 1

RNA

Question 2

A neutral atom must contain:

Answer 2

an equal number of protons and electrons

Question 3

Which of the following correctly describes chemical equilibrium?

Answer 3

Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.

Question 4

What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M?

Answer 4

pH 2

Question 5

If the pH of a solution is decreased from 9 to 8, it means that the:

Answer 5

concentration of H+ has increased tenfold (10X) and the concentration of OH- has decreased to one-tenth (1/10) what they were at pH 9.

Question 6

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3- and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+

If the pH of the blood increases, one would expect:

Answer 6

a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.

Question 7

A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it:

Answer 7

would function as both an acid and a base.

Question 8

Humans can digest starch but not cellulose because:

Answer 8

humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.

Question 9

The label on a container of margarine lists “hydrogenated vegetable oil” as the major ingredient. What is the result of adding hydrogens to vegetable oil?

Answer 9

The hydrogenated vegetable oil stays solid at room temperature.