Details of PH4108 (Autumn 2018)

Level: 4 Type: Theory Credits: 4.0

Course CodeCourse NameInstructor(s)
PH4108 Biological Physics Rumi De

Biological Physics course addresses the problems at the interface of physics and biology. It is an interdisciplinary course aimed for students majoring in physics, biology and also other disciplines who would like to explore and understand how life works. In this course, we will learn how physics laws can provide quantitative estimates of the different cellular behaviors functioning at various length scales and time scales.


  • Introduction: What is life, cells as building blocks of life;

  • Basic facts about cells: Nuclear and cytoskeletal elements, biopolymer, membrane, molecular motors, DNA, Proteins and other major large and small molecules;

  • Forces in the living world: Chemical forces, coulomb forces, Van der Waals interaction, electrostatic, hydrogen bonding, hydrophobic effect, entropic forces, depletion forces, excluded volume interaction;

  • Essential thermodynamics and statistical physics: Temperature, free energy, entropy, probability distribution, Boltzmann factor; Random walk models in biology.

  • Brownian motion and diffusion in biology: Active and passive transport, Fick's law, diffusion equation, diffusion with drift, biological applications of diffusion - modeling cell signaling problem, membrane transport, sedimentation, first passage time
    Life at low Reynolds number;

  • Physics of Biopolymers: What are polymers, biopolymers, polymerization, persistence length of polymers, size of polymers, radius of gyration, size of a Genome, polymer models - Freely joint chain, Self avoiding random walk, Worm-like chain; scaling laws, DNA loop formation;

  • Reaction kinetics; rate equations and dynamics in the cell: Simple models of cytoskeletal filament polymerization
    Dynamic of molecular machines- motors, ratchet models;

  • Biological electrostatics and electricity: Electrostatic potential, Bjerrum length, effect of screening, role of electricity in cells, action potential, nerve impulse propagation

  • Physics of Membrane: Structure, energetics and function;

  • Biomechanics: Elasticity theory, stress, strain, extension, bending of beam, buckling, torsion examples from biology;

(i) No prerequisite for physics major students;
(ii) Prerequisite for students from other disciplines: Thermodynamics and Elementary Statistical Physics.


  1. What is Life? E. Schroedinger, Canto Book Series, Cambridge University Press.
  2. Molecular Biology of the Cell, Alberts et al., 4th edition, Garland Science.
  3. Biological Physics: Energy, Information, Life Philip Nelson, W. H. Freeman Co.
  4. Physical biology of the cell Robert B. Phillips, Jan Kondev, Julie Theriot
  5. Random walks in biology H. Berg
  6. Intermolecular and surface forces Jacob N. Israelachvili., Academic Press
  7. Mechanics of Motor Proteins and the Cytoskeleton J. Howard
  8. Mathemetical Biology J. D. Murray
  9. Mechanics of the Cell David Boal, Cambridge University Press
  10. Statistical Thermodynamics of Surfaces, Interfaces, and membranes S. A. Safran
  11. The Theory of Polymer Dynamics M. Doi and S. F. Edwards
  12. Introduction to Polymer Physics M . Doi
  13. Scaling Concept in Polymer Physics P. G. De Gennes
  14. Principles of Condensed Matter Physics P. M. Chaikin and T. C. Lubensky
  15. Theory of elasticity L. Landau and E. Lifshitz
  16. Reading from the literature

Course Credit Options

Sl. No.ProgrammeSemester NoCourse Choice
1 IP 1 Elective
2 IP 3 Elective
3 IP 5 Not Allowed
4 MR 1 Not Allowed
5 MR 3 Not Allowed
6 MS 7 Elective
7 RS 1 Not Allowed
8 RS 2 Not Allowed