Introduction to biophysicsCourse Plan

Course ContentsReference Books

What is “Biophysics”Biophysics is a specialized sub area of biology

It is the science of physical principles of life itself

and of biological systems. Biophysics is an

interdisciplinary science that explains the laws

and principles of physics which govern various

biological processes. Biophysics spans all levels

of biological organization from molecular scale to

whole organism

Course PlanQuiz/Assignments: 10 marksSessionals: 20+20=40 marksTerminal: 50 marks

Course Contents Introduction to biophysicsBasic concepts

Osmosis, osmotic pressure, surface tension, diffusion, viscosity, thermal conduction, forces and energy

Molecular structure of biological systems at a glanceEnergetics and Dynamics of Biological Systems

Description of ATP, cell as an accumulator of electrochemical energy, energy consumption, respiration, mechanism of molecular energy transfer, thermodynamics and thermal molecular movement, mechanism of body temperature regulation, photosynthesis as a process of energy transfer and transformation, dynamics of blood flow, control of movement

Biological MembranesMembrane chemistry and structure, membrane physics, surface and interfacial tensions, diffusion and mobility of ions, electrostatic and mechanical properties of membranes

Mechanical Properties of Biological Materials fluid flow, blood circulation, muscle contraction, swimming, flying etc

Electric fields in cells and organismsNerve Signals, nerve impulses, nervous system

Physical factors of the environmentTemperature, pressure, mechanical oscillations (vibrations, sound, hearing and hearing aids, effect of ultrasound), electromagnetic fields in the environment, ionizing radiations

Course Contents

ebooksTextbook:

Biophysics by P. S. Mishra, 2010

Reference books:

Molecular And Cellular Biophysics by Meyer B. Jackson, Cambridge University Press, 2006

Biophysics by Roland Glaser, Springer, 2001An Introduction to Med. Biophysics by

Parveen Parkash

Biological activities happening in different organs of living body like kidney, liver, heart, lungs as well as those in intracellular and extracellular biological fluid are governed by fundamental laws of physics namely

DiffusionOsmosisViscositySurface Tension

OsmosisThe spontaneous passage of solvent from a solution of

lower concentration towards a solution of higher concentration when the two are separated by a semi permeable membrane is called osmosis

Osmosis is a special case of diffusion. It involves the diffusion of water through the semi permeable membrane to equalise the concentration of solutions on its two sides

Osmosis in fresh and sea water fish

Fresh water trout Sea water Herring

These cells are short of water; the tissue is limp and the plant is wilting

The cells have taken up water by osmosis; the cells are turgid and the tissue is firm

wilting Turgid plant

these cells will divide

vacuolesforming

cells absorb water by osmosis and expand

cell divisioncontinues

Growth in a shoot tip

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Effect of different solutions on blood cells

OsmosisOsmosis releases energy, and can be made to do

work, as when a growing tree root splits a stone. Diffusion and Osmosis are both types of PASSIVE

TRANSPORT - that is, no energy is required for the molecules to move into or out of the cell.

Osmosis takes place due to difference in chemical potentials of water on two sides of membranes which leads to pressure gradient

Solute decreases chemical potential of water. Water tends to flow from where its chemical potential is higher to where it is lower

Reduced chemical potential causes reduced vapor pressure, lower freezing point and higher boiling point of the solution as compared with pure water

Osmotic PressureOsmosis may be opposed by increasing the pressure in

the region of high solute concentration (hypertonic solution) with respect to that in the low solute concentration region (hypotonic solution).

The hydrostatic pressure which just stops osmosis is the osmotic pressure

The force per unit area, or pressure, required to prevent the passage of water through a selectively-permeable membrane and into a solution of greater concentration is equivalent to the osmotic pressure of the solution, or turgor.

Osmotic pressure is a colligative property, meaning that the property depends on the concentration of the solute but not on its identity.