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1. Science of Living System
BS10003 (2-0-0)
Dibyendu Samanta
School of Bioscience
Email: dibyendu.samanta@iitkgp.ac.in
Tel: 03222-284576
10th August, 2023

2. Characteristics of a Living System !!
• High degree of complexity.
• Mechanisms for sensing and responding to
alterations in surroundings.
• Capacity for precise self-replication and self-
assembly.
• Systems for extracting, transforming and using
energy from the environment.
• Ability to evolve.
Why Living System?

3. George de Mestral invented Velcro®: Unique,
two-sided fastener, one side with stiff hooks like
the burs and the other side with soft loops like
the fabric. a combination of the words velour
and crochet.
Invention of Velcro®: inspired by Cockleburs
Burdock
Why Living System?

4. Why Living System?
Shinkansen Bullet Train in Japan:
inspired by shape of Kingfisher head

5. Why Living System?
Tardigrades
Nature can’t make the dead come
back to life, but it can re-animate
the seemingly dead

6. Current Data
Usage !!

7. Digital DNA: Future storage device
for world’s data !!

8. Microsoft Corporation – DNA Storage Research
A DNA-Based Archival Storage System Bornholt J, et. al. ASPLOS 2016
(International Conference on Architectural Support for Programming Languages and
Operating Systems)
Digital DNA: Future storage device
for world’s data !!

11. Components of Living Systems
C-H-O-N-S-P
• All life forms on Earth are composed of building blocks
that are made of combinations of Carbon and other
elements:
• Hydrogen
• Oxygen
• Nitrogen
• Sulphur
• Phosphorus

12. Molecules of Living Systems:
Biological Macromolecules

13. BS10003 Topics (upto Midsem)
Lectu
re
Date Topic
1 10/08/2023
Nucleic acids: How is genetic information stored &
maintained
2 17/08/2023
Nucleic acids: How is genetic information stored &
maintained
3 24/08/2023
Transcription & Translation: How stored
information get processed
4 31/08/2023
Transcription & Translation: How stored
information get processed
5 07/09/2023 Institute Holiday
6 14/09/2023 Proteins: Structure-function and folding

14. Nucleic acids: How is genetic
information stored and maintained

15. Experiment that Proves DNA is Our Genetic Material

16. Experiment that Proves DNA is Our Genetic Material

17. RNA: Ribonucleic Acid
DNA: Deoxyribonucleic Acid
Nucleic Acid

18. Flow of Genetic Information: The Central
Dogma of Molecular Biology
RNA Protein
DNA
Transcription Translation
Replication
RNA Protein
DNA
Polymer of
nucleotides
Polymer of
nucleotides
Polymer of
amino acids

19. • Nucleic acids are polymers
• Monomer: Nucleotides
Nitrogenous bases
• Purines
• Pyrimidines
Sugar
• Ribose
• Deoxyribose
Phosphates
Nucleosides
Nucleotides
Nucleic Acid

20. (Ribose)
RNA - Ribonucleic Acid
DNA - Deoxyribonucleic Acid
RNA vs DNA
Ester Bond
N-β-glycosyl bond
(OH)
(H)

21. Two Types of Nitrogenous Bases

22. Purine and Pyrimidine Bases

23. Nucleotide = Nucleoside + Phosphate
(Nucleoside = Sugar + Base)

24. Nucleotide = Nucleoside + Phosphate
(Nucleoside = Sugar + Base)

25. Phosphodiester Linkages in the Covalent Backbone
of Nucleic Acid
3′ end
3′ end

26. RNA is Less Stable than DNA

27. Discovering the Structure of DNA
• Structure was discovered in 1953 by James
Watson and Francis Crick
• Awarded Nobel Prize in 1962
The Double Helix: A Personal Account of the Discovery of the
Structure of DNA - By James D Watson
X-ray Diffraction
Pattern of DNA

28. Some key features of DNA
• In DNA, two nucleic acid strands anneal together
through extensive inter-strand H-bonding between the
bases. This base pairing follows the rule proposed by
Watson and Crick.
• Chargaff’s rule: A always pairs with T and G pairs
with C
• Hence the two strands become complementary to each
other

29. DNA: Deoxyribonucleic Acid

30. DNA: Deoxyribonucleic Acid

31. Watson-Crick Model for the
Structure of DNA

32. Reversible Denaturation and
Annealing (Renaturation) of DNA
Increasing
Temp
Decreasing
Temp

33. Heat Denaturation of DNA

34. http://bcs.whfreeman.com/lehninger5e/