Exam 2: The Chemical Foundation of Life: Weak Interactions in an Aqueous Environment

Amphipathic molecules are not able to interact via van der Waals forces.

If hydroxide is added to an amino acid it will become increasingly ________ charged.

Glycine cannot serve as a buffer because it has two ionizable groups.

The pKa of each amino acid residue in a protein will not be influenced by the adjacent residue.

Calculate the pH of a weak acid that is 0.2% ionized in a 0.2 M solution.

Which of the following is TRUE of hydrophobic molecules?

Water is both a hydrogen bond donor and acceptor.

The ________ describes the tendency for hydrophobic molecules to aggregate because of the exclusion of water with the consequent increase of entropy of the solvent.

Calculate the acid dissociation constant Ka of a 0.2 M solution of weak acid that is 0.1% ionized.

Each of the following is a noncovalent interaction EXCEPT:

Small ions in biological fluids:

The net charge on an amino acid at its isoelectric point (pI) is ________.

Which of the following in biological compounds are sufficiently electronegative to serve as strong donors in a hydrogen bond?

Ionic compounds can be readily dissolved in water because the high dielectric constant of water screens and decreases the ________ force between the oppositely charged ions.

Calculate the pH of a 0.2 M acetate buffer (pKa = 4.77) that contains twice as much acid as conjugate base.

The average charge on an amino acid below its pI will be positive.

Which of the following is FALSE when considering van der Waals interactions?

Calculate the pH at the end of an enzyme-catalyzed reaction if it were carried out in a 0.1 M phosphate buffer, pH 6.86 and 0.005 M of acid was produced during the reaction?

The most important noncovalent interaction in biochemistry is the ________ bond.

Many proteins interact with DNA at physiological pH because: