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ATB · All 2025 papers

34 questions · 106 marks · 2 papers

Answer key

Indian Institute of Technology Madras

BS Degree Programme · Examination & Study Paper

Algorithmic Thinking in Bioinformatics

All 2025 papers

Official Paper

Examination Instructions & Guidelines

Solve on notebook/paper first before checking solutions.
MCQ: Exactly 1 option is correct. Negative marking applies.
MSQ: One or more options correct. Select all to score.
NAT: Numerical response. No negative marking.
Scientific calculator allowed for all calculations.
Official answer key is sealed at the end of this sheet.

End Term · 31 Aug 2025 (FN)End Term

Q1MCQ5 Marks·Choose one option
Key ↓
1. ATACC, ATGT, CGGC, ACTA
2. BACCT, TGTC, GGCG, CTAA
3. CTACC, TGTC, GGCG, CTAA
4. DACCT, ATGT, CGGC, ACTA
Q2MCQ5 Marks·Choose one option
Key ↓
1. A14
2. B41
3. C57
4. D128
Q3NAT5 Marks·Write the number
Key ↓
Your answer:
Q4NAT5 Marks·Write the number
Key ↓
Your answer:
Q5NAT5 Marks·Write the number
Key ↓
Your answer:
Read the passage below, then answer Q6–Q7
The de Bruijn graph of some linear (i.e., non-circular) genome Dna comprises of 2 nodes (N_1 and N_2) and 3 edges – two of these edges are directed from N_1 to N_2 and the remaining edge is directed from N_2 to N_1. To reconstruct Dna, you are allowed to start only from the node N_1. Answer the given subquestions with respect to the same.
Q6NAT2 Marks·Write the number
Key ↓
If the k-mers represented by both N_1 and N_2 are fixed, then how many unique genome sequences can be constructed from this de Bruijn graph? Enter the answer as a single integer.
Your answer:
Q7MSQ3 Marks·Choose all correct options
Key ↓
Suppose you don’t know the 2-mers representing N_1 and N_2. Then which of the following is/are possible choices for Dna?
1. ATATAT
2. BCACAC
3. CATATA
4. DAGAGG
5. ETGTGG
Read the passage below, then answer Q8–Q9
Based on the above data, answer the given subquestions.
Q8NAT3 Marks·Write the number
Key ↓
What is the value of the probability density function at x = 45 under this model? Round the answer to three decimal digits.
Your answer:
Q9NAT2 Marks·Write the number
Asked 2 times Key ↓
What is the probability that this data point was generated by the first cluster? Round the answer to three decimal digits.
Your answer:
Read the passage below, then answer Q10–Q12
You are asked to construct a phylogeny on the distance matrix D using the Additive Phylogeny algorithm. At the end of the 5th iteration, you notice the D^(bald) matrix consumes 81 units of memory space. Assume every entry in a matrix requires 1 unit of space. Also assume the count of the iterations starts from 1. Answer the given subquestions with respect to the same.
Q10NAT2 Marks·Write the number
Key ↓
How many units of space is required to the corresponding D^(trimmed) matrix? Enter the answer as a single integer.
Your answer:
Q11NAT2 Marks·Write the number
Key ↓
How many leaves will be there in the final phylogeny constructed at the end of the algorithm? Enter the answer as a single integer.
Your answer:
Q12NAT1 Mark·Write the number
Key ↓
Read the pseudocode carefully and calculate the number of iterations required by the UPGMA algorithm to construct the Ultrametric tree on D? Enter the answer as a single integer.
Your answer:
Read the passage below, then answer Q13–Q14
Based on the above data, answer the given subquestions.
Q13NAT4 Marks·Write the number
Key ↓
How many 6-mers in the sequence ‘ATTCCGGCCAACAG’ have a nonzero probability of binding to the TF according to the PWM given in the table? Enter the answer as a single integer.
Your answer:
Q14MCQ4 Marks·Choose one option
Key ↓
Which of the following substrings is most likely to be bound by the TF?
1. ATTCCGG
2. BCCGGCC
3. CATTCCG
4. DCCAACA
Read the passage below, then answer Q15–Q16
Based on the above data, answer the given subquestions.
Q15MCQ2 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D
Q16MCQ3 Marks·Choose one option
Asked 2 times Key ↓
1. A
2. B
3. C
4. D

Quiz 2 · 3 Aug 2025 (AN)Quiz 2

Q17MCQ5 Marks·Choose one option
Key ↓
1. AFigure I: Gibbs Sampling; Figure II: Randomized Motif Search; Figure III: Greedy Motif Search
2. BFigure I: Gibbs Sampling; Figure II: Greedy Motif Search; Figure III: Randomized Motif Search
3. CFigure I: Greedy Motif Search; Figure II: Randomized Motif Search; Figure III: Gibbs Sampling
4. DFigure I: Randomized Motif Search; Figure II: Gibbs Sampling; Figure III: Greedy Motif Search
Q18MCQ3 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D
Q19MCQ3 Marks·Choose one option
Asked 2 times Key ↓
1. A
2. B
3. C
4. D
Q20MCQ2 Marks·Choose one option
Asked 2 times Key ↓
1. A
2. B
3. C
4. D
Q21MCQ2 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D
Q22MSQ3 Marks·Choose all correct options
Key ↓
Which of the following statements about additive distance matrices are true?
1. AEvery 3 x 3 distance matrix is additive.
2. BEvery 4 x 4 distance matrix is additive.
3. CThere exists a 3 x 3 distance matrix that is not additive.
4. DThere exists a 4 x 4 distance matrix that is not additive.
5. EFor every additive distance matrix, there exists a simple tree fitting the matrix.
Q23NAT3 Marks·Write the number
Key ↓
Your answer:
Q24NAT4 Marks·Write the number
Key ↓
Your answer:
Read the passage below, then answer Q25–Q27
Q25NAT3 Marks·Write the number
Key ↓
What is the number of edges in the corresponding suffix trie? Enter the value as a single integer.
Your answer:
Q26NAT2 Marks·Write the number
Key ↓
What is the length of the reference sequence from which this suffix tree has been constructed? Include $ in the calculation of length. Enter the value as a single integer.
Your answer:
Q27MCQ3 Marks·Choose one option
Key ↓
Use the given suffix tree to determine which of the following is the suffix array for the reference sequence ? Assume $ comes first in the alphabet.
1. A[7, 6, 5, 3, 1, 4, 2, 0]
2. B[7, 6, 5, 3, 1, 4, 0, 2]
3. C[7, 5, 3, 1, 6, 4, 2, 0]
4. D[7, 5, 3, 1, 6, 4, 0, 2]
5. ENone of these
Read the passage below, then answer Q28–Q30
Q28MCQ2 Marks·Choose one option
Key ↓
Find the consensus of the motifs?
1. ATCATGA
2. BAACCGT
3. CTCTAAA
4. DTCATAA
Q29NAT2 Marks·Write the number
Key ↓
Your answer:
Q30NAT4 Marks·Write the number
Key ↓
Calculate the entropy of the first column. Round up the answer to 3 decimal places.
Your answer:
Read the passage below, then answer Q31–Q32
Q31MCQ5 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D
Q32MCQ4 Marks·Choose one option
Key ↓
Which of the following represents the distance matrix for the next iteration?
1. A
2. B
3. C
4. D
Read the passage below, then answer Q33–Q34
Q33MCQ2 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D
Q34MCQ1 Mark·Choose one option
Key ↓
1. A
2. B
3. C
4. D
5. E

Official Key

Master Answer Key & Explanations

Official answer keys from IIT Madras BS past papers. Click any question to review.

Reveal Key

Q1D

Q2B

Q34

Q411

Q54

Q61

Q7A, B, C

Q80.06 to 0.07

Q90.36 to 0.38

Q1064

Q1113

Q1212

Q133

Q14D

Q15A

Q16C

Q17B

Q18C

Q19D

Q20A

Q21C

Q22A, D, E

Q2316

Q243

Q2532

Q268

Q27C

Q28D

Q2916

Q301.57 to 1.58

Q31C

Q32A

Q33A

Q34C

Questions and answer keys are reproduced from the official IIT Madras BS papers. BTechi is not affiliated with IIT Madras.