Amino acids and Peptides 2024

Which amino acid is necessary for hemoglobin synthesis?

• A. Valine

• B. Isoleucine

• C. Proline

• D. Glycine
  

• Answer: B. Isoleucine

What is the distinguishing feature of a zwitterion?

• A. Net positive charge

• B. Net negative charge

• C. No net charge but carries both positive and negative charges

• D. Neutral molecule without any charges

Answer: C. No net charge but carries both positive and negative charges

Which amino acid has a non-polar side chain?

• A. Aspartic acid

• B. Glycine

• C. Tyrosine

• D. Lysine

Answer: B. Glycine

What type of bond forms between amino acids in a peptide?

• A. Hydrogen bond

• B. Ionic bond

• C. Peptide bond

• D. Disulfide bond

Answer: C. Peptide bond

Which peptide hormone helps regulate blood pressure?

• A. Vasopressin

• B. Oxytocin

• C. Angiotensin

• D. Glutathione

Answer: C. Angiotensin

What is the classification of amino acids with positively charged side chains?

• A. Non-polar

• B. Acidic

• C. Basic

• D. Polar

Answer: C. Basic

Which of the following is a peptide used as a reducing agent?

• A. Aspartame

• B. Glutathione

• C. Vasopressin

• D. Oxytocin

• Answer: B. Glutathione

What determines the N-terminal of a peptide?

• A. The first amino acid with a free carboxyl group

• B. The first amino acid with a free amino group

• C. The last amino acid in the sequence

• D. The amino acid with the largest side chain

Answer: B. The first amino acid with a free amino group

How are proteins classified by size?

• A. Oligopeptides

• B. Dipeptides

• C. Polypeptides

• D. All of the above

Answer: D. All of the above

What is the primary function of oxytocin?

• A. Stimulates milk production

• B. Stimulates uterine contractions

• C. Reduces urination

• D. Maintains blood pressure

Answer: B. Stimulates uterine contractions

Glycine is the only amino acid that is achiral.

Answer: True

All amino acids in proteins are in the D-configuration

Answer: False
Explanation: All amino acids in proteins are in the L-configuration.

Zwitterions have no net charge at physiological pH.

Answer: True

Aspartic acid and glutamic acid are basic amino acids.

Answer: False
Explanation: They are acidic amino acids.

A peptide bond forms via hydrolysis.

Answer: False
Explanation: A peptide bond forms via a condensation reaction.

Non-polar amino acids are hydrophobic and cluster inside proteins.

Answer: True

Essential amino acids can be synthesized by the body.

Answer: False
Explanation: Essential amino acids must be obtained from the diet.

Glutathione protects red blood cell membranes.

Answer: True

Peptides are written from the C-terminal to the N-terminal.

Answer: False
Explanation: Peptides are written from the N-terminal to the C-terminal.

Vasopressin reduces fluid loss by controlling urination.

Answer: True

What is the general structure of an amino acid?

Answer: A central α-carbon attached to an amino group, carboxyl group, side chain (R group), and hydrogen atom.

Name three essential amino acids.

Answer: Isoleucine, lysine, and tryptophan.

What is the role of glutathione?

Answer: It acts as an intracellular reducing agent, protects cell membranes, and aids in amino acid transport.

What are the four categories of amino acid side chains?

Answer: Non-polar, uncharged polar, acidic, and basic.

How does a peptide bond form?

Answer: Through a condensation reaction between the α-carboxyl group of one amino acid and the α-amino group of another.