Fundamentals of Medicinal Chemistry

(8) (a) The main differences are the following.

. DNA molecules usually have a very large RMM value compared to RNA

molecules.

. The structure of RNA contains the sugar residue ribose whilst that of DNA

contains the sugar deoxyribose.

. RNA moleculesconsistof asinglestrandofnucleotides whilst DNA molecules

consist of two nucleotide strands in the form of a supercoiled double helix.

(b) See Section 1.6.5.

(9) The first four codons are not involved in protein synthesis. Protein synthesis starts

with AUG and stops with UAA. The peptide coded by the codons between the stop

and start signals is

Met–Pro–Arg–Gly–Gly–Try

Chapter 2

(1) (a) See Section 2.3. (b) See section 2.6. (c) See section 2.6. (d) See section 2.3. (e) See

section 2.7.1.

(2) The nature of the pathological target. Its site of action, the nature of the desired

action, its stability, ease of absorption and distribution, metabolism, dosage form

and regimen.

(3) See Section 2.6.

(4) For definitions see Section 2.7. The factors affecting the pharmacokinetic phase are

ADME. The factor affecting the pharmacodynamic phase is the stereoelectronic

structure of the drug molecule.

(5) The reduction in pH reduces the negative charge of the albumin and so increases its

electrophilic character. Therefore, as amphetamine molecules are nucleophilic in

nature, their binding should improve with decrease in pH. Part of this binding will

will involve salt formation between the amphetamine and the albumin. Amphet-

amine is more likely to form salts in which it acts as the positive ion as the

electrophilic nature of the albumin decreases with increase in pH.

(6) See Table 2.1.

262 ANSWERS TO QUESTIONS