QUIZ 1, BICH 410( MWF 1:50 PM), Friday, Sept. 8, 1995
Clearly circle the letter corresponding to your answer for each problem. There are seven problems, six of which count 3 points, and one is worth 2 points. No partial credit given for multiple-choice questions.
1) Condensation of an amino group and a carboxyl group with loss of water forms a(n):
- A) ester
- B) guanidine
- C) amide
- D) carbonyl
- E) imidazole
2) The enthalpy change deltaH for the formation of ammonia from hydrogen and nitrogen is -46 kJ/mol. This reaction is:
- A) at equilibrium
- B) endergonic
- C) exergonic
- D) exothermic
- E) endothermic
3) Which of these statements about hydrogen bonds is not true?
- A) Individual hydrogen bonds are much weaker than covalent bonds.
- B) In liquid water, the average water molecule forms hydrogen bonds with 3 to 4 other water molecules.
- C) Hydrogen bonds account for the anomalously high boiling point of water.
- D) Individual hydrogen bonds in aqueous water exist for many seconds and sometimes for minutes.
- E) Hydrogen bonds are highly directional.
4) The hydrophobic effect:
- A) does not contribute to the structure of water-soluble proteins.
- B) refers to the ability of water to denature proteins.
- C) primarily involves the effect of polar solutes on entropy in aqueous systems.
- D) involves stabilization energies of approximately 100 kJ/mol.
- E) is the driving force in the formation of micelles of amphipathic compounds in water.
5) The reaction shown below is an example of what type of biochemical reaction?
(pyruvate to lactate; reaction shown on sidebar of page 416 in text)
- A) condensation
- B) oxidation-reduction
- C) group transfer
- D) cleavage
- E) rearrangement
6) Which of the following functional groups could be involved in a hydrogen bond with a primary amino group?
- A) methyl group
- B) phenyl group
- C) carbonyl (ketone)
- D) ethyl group
- E) none of the above
7) (2 pts) Which of the following interactions has the weakest stabilization energy?
- A) hydrogen bond
- B) van der Waals interaction
- C) hydrophobic interaction
- D) carbon-carbon covalent bond
- E) ionic interaction in aqueous solution