Homework 4

Question 1

In a hydrogen bond between a water molecule and another biomolecule, ______.

the partial charge on a hydrogen of the water molecule interacts with the partial charge on a hydrogen of the other molecule

the hydrogen bond will typically form between a hydrogen atom of the water molecule and either a nitrogen, sulfur, or oxygen atom of the other molecule

a hydrogen ion on the water molecule forms an ionic bond with a hydride ion on the other molecule

a hydrogen on the water molecule forms a covalent bond with a hydrogen atom on the other molecule.

the hydrogen atom is located between an oxygen atom of the water and a carbon atom of the other molecule

Answer 1

the hydrogen bond will typically form between a hydrogen atom of the water molecule and either a nitrogen, sulfur, or oxygen atom of the other molecule

Question 2

Which of the following would be the strongest acid?

formic acid, pK = 3.75

succinic acid, a diprotic acid with pK = 4.21 and 5.64

acetic acid, pK = 4.76

ammonium ion, pK = 9.25

cannot be determined from the given information

Answer 2

formic acid, pK = 3.75

Question 3

Which one of the following statements about enzyme catalyzed reactions is FALSE?

Enzymes catalyze reactions at their active site.

Many enzymes change shape upon substrate binding.

Enzymes lower the free energy change for the reactions they catalyze.

Enzymes form complexes with their substrates.

Answer 3

Enzymes lower the free energy change for the reactions they catalyze.

Question 4

For a Michaelis-Menten enzyme, Vmax remains the same whereas KM increases for which type of inhibition?

mixed

competitive

uncompetitive

suicide

Answer 4

competitive

Question 5

Azidothymidine (AZT) is an example of an antiretroviral drug used to treat HIV infection through enzyme inhibition. Its structure is shown below. What class of drug is this ________________. ? What kind of inhibitor is it ____________

Answer 5

Reverse transcriptase inhibitor, competitive.