Question 1

Which of the following functional groups is NOT present in the structure of acetylsalicylic acid (aspirin)?

Accepted Answer

Amino group

Question 2

Which carbon atom in the structure of aspirin is chiral?

Accepted Answer

None of the carbons are chiral

Question 3

The molecule shown in image 2 is an example of which type of stereoisomer?

Accepted Answer

Enantiomer

Question 4

Why do Dexedrine and Benzedrine, which have identical chemical formulas, differ in their biological activity?

Accepted Answer

They are different enantiomers, and only one fits the biological target optimally

Question 5

Which of the following best explains why water is a polar molecule?

Accepted Answer

The oxygen atom is more electronegative than hydrogen, and the molecule is bent

Question 6

Which property of water is primarily responsible for its high surface tension?

Accepted Answer

Hydrogen bonding

Question 7

Refer to image 3. What does the arrangement of water molecules around the hydrophobic solute in panel A illustrate?

Accepted Answer

Formation of clathrate structures, decreasing entropy

Question 8

Using the van der Waals energy diagram (image 4), what happens if two non-bonded atoms approach closer than the van der Waals contact distance?

Accepted Answer

They experience strong repulsion

Question 9

The molecule shown in image 5 contains which three functional groups?

Accepted Answer

Amino, methyl, and carboxyl

Question 10

Which of the following best describes the effect of storing glucose as glycogen in animal cells?

Accepted Answer

It decreases osmotic pressure, preventing water influx and cell lysis

Question 11

Calculate the osmotic pressure ($$\Pi) of a 0.1 M $$NaCl solution at 300 K, assuming complete dissociation. Use $$R = 0.0821 L $$atm K$$^{-1}$$ mol$$^{-1}. ($$Hint: $$\Pi = iMRT$$, $$i$$ for NaCl = 2)

Accepted Answer

$$\Pi = 4.93$$ atm

Question 12

What is the pH of a solution with $$[OH^-] = 1.5 	imes 10$$^{-3}$$ M? (Assume $$[H^+][OH^-] = 1.0 	imes $$10^{-14} at 25$$°C)

Accepted Answer

pH = 2.82

Question 13

Which of the following statements about the peptide bond is correct?

Accepted Answer

It is planar due to partial double-bond character from resonance

Question 14

Which amino acid is the only non-chiral genetically coded natural amino acid?

Accepted Answer

Glycine

Question 15

Which vitamin deficiency leads to scurvy, and how does it affect collagen structure?

Accepted Answer

Vitamin C; it prevents hydroxylation of proline, destabilizing collagen triple helix

Question 16

Which amino acid is most commonly mutated in osteogenesis imperfecta, and why does this cause severe symptoms?

Accepted Answer

Glycine; its small size is essential for tight packing in collagen triple helix

Question 17

Which of the following best explains why the hydrophobic effect increases entropy?

Accepted Answer

Water molecules are released from ordered clathrate cages around nonpolar solutes

Question 18

Which of the following is true about the net charge of aspartame at physiological pH (7.4)?

Accepted Answer

It is neutral because both the amino and carboxyl groups are ionized

Question 19

Why can't patients with phenylketonuria (PKU) consume products containing aspartame?

Accepted Answer

They cannot metabolize phenylalanine, leading to toxic buildup

Biochemistry Exam 1 Study Guide – Foundations, Water, Amino Acids, Protein Structure

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