Question 1

Which of the following functional groups is most likely to be ionized at physiological pH (pH ~7.4)?

Accepted Answer

Carboxylate ($$R-COO^-)$$

Question 2

A peptide bond is formed between two amino acids by which type of chemical reaction?

Accepted Answer

Condensation (dehydration synthesis)

Question 3

Which of the following best describes the strength order of non-covalent interactions in biomolecules?

Accepted Answer

Charge-charge \u003e hydrogen bond \u003e hydrophobic \u003e van der Waals

Question 4

Given the titration curve of glycine, at what pH does glycine exist predominantly as a zwitterion?

Accepted Answer

At its isoelectric point ($$pI)$$

Question 5

Which equation is used to calculate the pH of a buffer solution containing a weak acid and its conjugate base?

Accepted Answer

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

Question 6

Which of the following amino acids is most likely to form a disulfide bond?

Accepted Answer

Cysteine

Question 7

What is the standard free energy change ($$\Delta G^\circ) $$for a redox reaction in which 2 electrons are transferred and the difference in standard reduction potential ($$\Delta E^\circ) is 1.0 V$$? (Faraday constant $$F = 96.48 kJ V$^{-1}$$ mol$$^{-1})$$

Accepted Answer

$$\Delta G^\circ = -192.96 kJ/$$mol

Question 8

Which of the following statements about the structure of water is TRUE?

Accepted Answer

Water has a tetrahedral geometry with a bond angle of approximately 104.5°

Question 9

Which functional group is present in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 10

Which of the following best explains why proteins fold into specific three-dimensional structures?

Accepted Answer

A combination of covalent and non-covalent interactions, including hydrophobic effects, hydrogen bonds, and charge-charge interactions, stabilize the folded structure

Question 11

Which of the following is a correct statement about the isoelectric point ($$pI) of an $$amino acid?

Accepted Answer

It is the pH at which the amino acid carries no net charge

Question 12

Which of the following best describes the role of 2,3-bisphosphoglycerate (2,3-BPG) in hemoglobin function?

Accepted Answer

It stabilizes the T-state and promotes oxygen release in tissues

Question 13

Which of the following equations correctly relates the equilibrium constant ($$K_{eq}) to $$the standard free energy change ($$\Delta G^\circ$$)?

Accepted Answer

$$\Delta G^\circ = -RT \ln K_{eq}$$

Question 14

Which of the following amino acids is aromatic and contributes to protein absorbance at 280 nm?

Accepted Answer

Tryptophan

Question 15

Which of the following is TRUE regarding the dipole moment of water?

Accepted Answer

It is directed from the hydrogen atoms toward the oxygen atom

Question 16

Which of the following best describes the effect of pH on the ionization state of amino acids?

Accepted Answer

At pH above the $$pK_a of a $$group, the group is mostly deprotonated

Question 17

Which of the following is a consequence of the resonance in the peptide bond?

Accepted Answer

The peptide bond is planar and has partial double-bond character

Question 18

Which of the following is TRUE about the Bohr effect in hemoglobin?

Accepted Answer

Lower pH decreases hemoglobin's affinity for oxygen, promoting oxygen release

Question 19

Which of the following best describes the hydrophobic effect in protein folding?

Accepted Answer

It is driven by the increase in entropy as water molecules are released from nonpolar surfaces

Fundamental Chemical Principles and Biomolecular Structure in Biochemistry

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