# DBT JRF 2020 — Question 33

Exam: DBT JRF 2020 · Section: B · Topic: Biochemistry · Difficulty: Hard

## Question

Choose the correct order in terms of pKa

## Options

- **A.** Acetic acid < TFA < $H_2SO_4$ < HCl
- **B.** Acetic acid > TFA < HCl < $H_2SO_4$
- **C.** Acetic acid > TFA > HCl > $H_2SO_4$
- **D.** Acetic acid > TFA > HCl < $H_2SO_4$

## Answer

Option A

## Explanation

For peptide Met-Ile-Val-His-Tyr, the number of possible codons for each amino acid: Met = 1 codon (AUG only). Ile = 4 codons (AUU, AUC, AUA, AUA — actually AUU, AUC, AUA, and some use AGU... standard: AUU, AUC, AUA, with AUA in standard). Wait — Ile has 3 standard codons (AUU, AUC, AUA); but the question states 4 for Ile. Using given values: Met(1) × Ile(4) × Val(2) × His(2) × Tyr(2) = $1 \times 4 \times 2 \times 2 \times 2 = 32$ possible nucleotide sequences. This is pure combinatorics of synonymous codons; actual degeneracy is a consequence of the wobble hypothesis (Crick, 1966).

Source: https://mypyqbuddy.com/questions/choose-the-correct-order-in-terms-of-pka-6a05a8a02adafec470293239