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ATB · Phylogenetic trees

7 questions · 21 marks · 2 papers

Answer key

Indian Institute of Technology Madras

BS Degree Programme · Examination & Study Paper

Algorithmic Thinking in Bioinformatics

Phylogenetic trees

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

Read the passage below, then answer Q1–Q3
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.
Q1NAT2 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:
Q2NAT2 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:
Q3NAT1 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:

Quiz 2 · 3 Aug 2025 (AN)Quiz 2

Q4MSQ3 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.
Q5NAT4 Marks·Write the number
Key ↓
Your answer:
Read the passage below, then answer Q6–Q7
Q6MCQ5 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D
Q7MCQ4 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

Official Key

Master Answer Key & Explanations

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

Reveal Key

Q164

Q213

Q312

Q4A, D, E

Q53

Q6C

Q7A

Questions and answer keys are reproduced from the official IIT Madras BS papers. Topics and repeated question types are BTechi’s own grouping. BTechi is not affiliated with IIT Madras.