FiltersDone

Question type

Essay

Multiple Choice

Short Answer

True False

Matching

Exam 15: Biomolecules: Amino Acids, Peptides, and Proteins

Show Answer

Share

---

All types

Filters

Study Flashcards

Question 21

Multiple Choice

Review LaterAdd Note

Review Later

Which of the following tripeptides is not hydrolysed by trypsin?

A) Glu-Arg-Ser
B) Arg-Glu-Thr
C) Glu-Ser-Arg
D) Lys-Ser-Arg

Correct Answer

verified

Show Answer

Question 22

Essay

Review LaterAdd Note

Review Later

Instructions: Match a structure from the list below to each of the following terms.

Correct Answer

verified

Show Answer

Question 23

Multiple Choice

Review LaterAdd Note

Which of the following amino acids has a non-polar side chain?

Write the equation for the reaction, using methanol (CH₃OH), that would render the carboxyl group of alanine unreactive.

Which of the following amino acids has a sulfur-containing side chain?

Define isoelectric point.

Show the steps involved in a synthesis of F-G-I using the Merrifield procedure.

Instructions: Consider the following structure. Based on this structure answer the following question(s). Refer to instructions. Name the peptide using both the three-letter and one-letter codes.

Instructions: Refer to the data below to answer the following question(s). Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pK_a1 = 2.36 and pK_a2 = 9.60. Refer to instructions. Draw the structure of the predominant form of leucine at pH = 10.00.

During peptide synthesis, the carboxylic acid group may be protected as the methyl ester. Aqueous base hydrolysis is utilized to remove the ester protecting group. Write the complete stepwise mechanism for the hydrolysis of the methyl ester of BOC-Val-Gly-OCH₃, above. Show all intermediate structures and all electron flow with arrows.

Instructions: Consider the following structure. Based on this structure answer the following question(s). Refer to instructions. Circle the peptide bonds.

Instructions: Match a structure from the list below to each of the following terms.

Premises

Responses

A peptide containing eight amino acid residues with a C-terminal valine.

An amino acid in its zwitterionic form.

Source from which many coenzymes are derived.

Val-Phe-Leu-Met-Tyr-Pro-Gly-Trp-Cys-Glu

A polypeptide which gives four fragments on treatment with chymotrypsin.

A peptide coupling reagent.

The product of an Edman degradation.

Asp-Tyr-Ile-His-Pro-Phe-Arg-Val

An amino acid with a protected carboxyl group.

apoenzyme

Val-Lys-Phe-Gly-Arg-Met-Arg-Phe

vitamins

Premises

A peptide containing eight amino acid residues with a C-terminal valine.

An amino acid in its zwitterionic form.

Source from which many coenzymes are derived.

A polypeptide which gives four fragments on treatment with chymotrypsin.

A peptide coupling reagent.

The product of an Edman degradation.

An amino acid with a protected carboxyl group.

Responses

Val-Phe-Leu-Met-Tyr-Pro-Gly-Trp-Cys-Glu

Asp-Tyr-Ile-His-Pro-Phe-Arg-Val

apoenzyme

Val-Lys-Phe-Gly-Arg-Met-Arg-Phe

vitamins

Show Answer

Correct Answer

Premises

Responses

Val-Phe-Leu-Met-Tyr-Pro-Gly-Trp-Cys-Glu

Asp-Tyr-Ile-His-Pro-Phe-Arg-Val

apoenzyme

Val-Lys-Phe-Gly-Arg-Met-Arg-Phe

vitamins

Premises

Val-Phe-Leu-Met-Tyr-Pro-Gly-Trp-Cys-Glu

Asp-Tyr-Ile-His-Pro-Phe-Arg-Val

apoenzyme

Val-Lys-Phe-Gly-Arg-Met-Arg-Phe

vitamins

Responses

Instructions: Refer to the data below to answer the following question(s). Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pK_a1 = 2.36 and pK_a2 = 9.60. Refer to instructions. Draw a Fischer projection of L-leucine and label the chirality center(s) as R or S.

Instructions: Refer to the data below to answer the following question(s). Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pK_a1 = 2.36 and pK_a2 = 9.60. Refer to instructions. Leucine is described as an essential amino acid. What does this mean?

Which of the following reagents can be used to cleave a tert-butoxycarbonyl (Boc) protecting group from a peptide?

Refer to the data below to answer the following questions: The octapeptide saralasin is a specific antagonist of angiotensin II. A derivative of saralasin is used therapeutically as an antihypertensive. Amino acid analysis of saralasin show the presence of the following amino acids: Ala, Arg, His, Pro, Sar, Tyr, Val₂ Refer to instructions. Sar is the mnemonic for sarcosine, N-methyl aminoethanoic acid. Draw the structure of sarcosine.

To what structural feature does the term "primary structure" refer?

Instructions: Refer to the data below to answer the following question(s). Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pK_a1 = 2.36 and pK_a2 = 9.60. Refer to instructions. How many possible stereoisomers of leucine are there?

Which of the following tripeptides is not hydrolysed by chymotrypsin?

BOC protecting groups are generally removed by treatment with trifluoroacetic acid. On the structures provided below, draw arrows consistent with electron flow in the mechanism of this reaction.