Thermodynamics of globular protein folding in water:

• Glutamic acid carries a negatively charged carboxylate side chain (hydrophilic) that interacts favorably with surrounding water molecules on the protein exterior surface.
• Aspartic acid is similarly a charged, polar hydrophilic residue that segregates to the outer surface.
• Lysine carries a positively charged ammonium side chain (hydrophilic) exposed on the external solvent interface.
• Phenylalanine possesses a bulky nonpolar aromatic benzyl side chain that is hydrophobic and buries within the interior core of the folded protein away from water.

Genetically encoded standard vs modified amino acids:

• Hydroxyproline is a non-standard amino acid produced exclusively by post-translational enzymatic hydroxylation of proline residues (by prolyl 4-hydroxylase) within collagen; it has no dedicated tRNA or mRNA triplet codon.
• Histidine is a standard canonical amino acid encoded by codons CAU and CAC.
• Tyrosine is a standard canonical amino acid encoded by codons UAU and UAC.
• Cysteine is a standard canonical amino acid encoded by codons UGU and UGC.

Stereochemistry and mutarotation of glucose anomers:

• Assertion (A) is true: Pure crystalline $\alpha$-D-glucopyranose has an initial specific rotation of $+112.2^\circ$, while pure $\beta$-D-glucopyranose has an initial rotation of $+18.7^\circ$. When either anomer is dissolved in water, mutarotation spontaneously occurs via reversible open-chain ring opening until both solutions settle at an identical final optical rotation of $+52.7^\circ$.
• Reason (R) is true: The spontaneous mutarotation process converges on an identical thermodynamic equilibrium mixture containing approximately $64\%\;\beta$-anomer, $36\%\;\alpha$-anomer, and $\lt 0.02\%$ open-chain form.
• Because both solutions converge on the exact same molecular composition at equilibrium, their macroscopic optical rotation properties become completely identical, meaning Reason (R) is the direct explanation of Assertion (A).