3718106678

3718106678 - Chemistry 3785 Sample First Hour Exam 100...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chemistry 3785 Sample First Hour Exam Name KEY 100 points Points Score Points Score I 48 IV 12 II 14 V 14 III 12 Total 100 A table of pK values for the 20 standard amino acids is found on page 7. I. (48) Multiple Choice. Circle the letter corresponding to the best choice. Three points each. 1. Phosphoric acid, H 3 PO 4 , is a polyprotic acid with three ionizable protons. The pK values for each ionization are as follows: pK 1 = 2.15, pK 2 = 6.82, and pK 3 = 12.38. At pH 6.82 we know that a. The predominate form of the acid is H 3 PO 4 . b. The predominate form of the acid is the diprotic form, H 2 PO 4 - . c. The concentration of the diprotic form, H 2 PO 4 - , is equal to the concentration of the monoprotic form, HPO 4 2- . d. The predominate form of the acid is the monoprotic form, HPO 4 2- . e. The concentration of the monoprotic form, HPO 4 - , is equal to the concentration of the phosphate ion, PO 4 3- . 2. What percentage of the thiols of cysteine exist in the protonated form at pH 9.00? a. 19% b. 81% c. 23% d. 77% e. 91% 3. What is true of the hydrophobic effect? a. The spontaneous transfer of a nonpolar solute from an aqueous to a nonpolar solvent is primarily due to an increase in enthalpy. b. It causes hydrophilic amino acids to fold inside a protein and hydrophobic amino acids to be on the protein’s surface. c. The spontaneous transfer of a nonpolar solute from an aqueous to a nonpolar solvent is primarily due to a decrease in entropy. d. The spontaneous transfer of a nonpolar solute from an aqueous to a nonpolar solvent results in the disruption of the hydrogen bonded “cage” of water about the solute. e. both c and d. 4. Which figure illustrates the correct structure of adenosine monophosphate? a. b. c. d. e. N N N N NH 2 O OH OH CH 2 O P O - O O - N N N N NH 2 O O OH P O O - - O HOCH 2 HN N N N H 2 N O O OH OH OCH 2 P O - O O - N N N N NH 2 O OH OH - O P O O - O CH 2 HN N N N H 2 N O O O OH CH 2 OH P O - O O -
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 5. What is the complementary RNA sequence of the DNA sequence 5 GATCCAA 3 ? a. 5 GAUCCAA 3 b. 5 AACCTAG 3 c. 5 CUAGGUU 3 d. 5 UUGGAUC 3 e. 5 TTGGATC 3 6. Which of the following amino acids are classified as uncharged but polar: Ser, Arg, Asn, Asp? a.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 7

3718106678 - Chemistry 3785 Sample First Hour Exam 100...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online