# DBT JRF 2020 — Question 22

Exam: DBT JRF 2020 · Section: B · Topic: Bioprocess Engineering · Difficulty: Easy

## Question

Which of the combination of gases is finally produced during anaerobic digestion?

## Options

- **A.** $N_2 + NH_3$
- **B.** $CO_2 + CO$
- **C.** $CH_4 + CO_2$
- **D.** $CO + N_2$

## Answer

Option C

## Explanation

Global pairwise sequence alignment (Needleman-Wunsch) of CGAATTTGG (query, 9 nt) vs each option with scoring: match=+1, mismatch=0, gap penalty=-1. Alignment vs CGTTTGG (7 nt): CGA-TTTGG / CGTTTGG → optimal: CGA--TTTGG vs -CGTTTGG-- → best global alignment gives ~5 matches with 2 gaps = 5-2=3, or CG-ATTTGG vs CGTTTGG- → 7 positions: CG=2 matches, gap=-1, TTTGG=5 matches at partial, scoring is complex. Detailed calculation yields the highest similarity score for CGTTTGG among the four options.

Source: https://mypyqbuddy.com/questions/which-of-the-combination-of-gases-is-finally-6a05a8a02adafec47029322e