Question 1

Which of the following amino acids contains a sulfur atom in its side chain and is classified as non-polar aliphatic?

Accepted Answer

Methionine

Question 2

What is the correct formula to calculate the isoelectric point (pI) of an amino acid with only two ionizable groups?

Accepted Answer

$$pI = \frac{pK_{a1} + pK_{a2}}{2}$$

Question 3

Which protein function is performed by hemoglobin?

Accepted Answer

Transport and carrier protein

Question 4

Which amino acid is classified as aromatic and has a hydroxyl group in its side chain?

Accepted Answer

Tyrosine

Question 5

What is the main reason peptide bonds are planar?

Accepted Answer

They have partial double bond character due to resonance

Question 6

Which equation describes the relationship between pH, pKa, and the ratio of conjugate base to acid in a buffer solution?

Accepted Answer

$$pH = pK_a + \log_{10} \left( \frac{[A^-]}{[HA]} \right)$$

Question 7

Which amino acid is NOT optically active?

Accepted Answer

Glycine

Question 8

During the titration of glycine, at which pH does the isoelectric point (pI) occur?

Accepted Answer

pH 5.97

Question 9

Which of the following is a positively charged (basic) amino acid at physiological pH?

Accepted Answer

Arginine

Question 10

Which uncommon amino acid is a derivative of proline and found in plant cell wall proteins?

Accepted Answer

4-hydroxyproline

Question 11

What is the effect of 'salting out' on protein solubility?

Accepted Answer

Protein solubility decreases, leading to precipitation

Question 12

Which amino acid is classified as both ketogenic and glucogenic?

Accepted Answer

Isoleucine

Question 13

Which of the following statements about peptide bonds is TRUE?

Accepted Answer

Rotation around the peptide bond is not permitted

Question 14

Which protein structure level is defined by the sequence of amino acids?

Accepted Answer

Primary structure

Question 15

Which of the following is a function of chaperone proteins?

Accepted Answer

Assist in protein folding to ensure proper conformation

Question 16

Which amino acid can form a disulfide bond, contributing to protein stability?

Accepted Answer

Cysteine

Question 17

What is the correct interpretation of the Beer-Lambert Law in protein estimation?

Accepted Answer

Absorbance is directly proportional to concentration and path length

Question 18

Which amino acid is essential and has a branched aliphatic side chain?

Accepted Answer

Valine

Question 19

Which of the following best describes a zwitterion?

Accepted Answer

A molecule with both positive and negative charges but net charge zero

Question 20

Which amino acid is classified as polar uncharged and contains an amide group in its side chain?

Accepted Answer

Asparagine

Amino Acids and Proteins: Structure, Properties, and Biochemical Significance

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