introduction to biophysics course plan course contents diffusion osmosis
TRANSCRIPT
Introduction to biophysicsCourse Plan
Course ContentsDiffusionOsmosis
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 Plan
Quiz/Assignments: 15-20 marksSessionals: 30-35 marksTerminal: 50 marks
Course ContentsIntroduction to biophysicsForces governing biological processesEnergetics and dynamics of biological
systemsBiomechanics
fluid flow, blood circulation, muscle fluid flow, blood circulation, muscle contraction, lever system of the body etccontraction, lever system of the body etc
Membrane physics
Course ContentsElectrical properties of cells
Nerve Signals, nerve impulses, cardiac cycle Nerve Signals, nerve impulses, cardiac cycle and electrocardiography (ECG)and electrocardiography (ECG)
Physics of five senses
sense of sight, hearing, taste, touch and sense of sight, hearing, taste, touch and smellsmell
Physical factors of the environment
Temperature, pressure, mechanical Temperature, pressure, mechanical oscillations (vibrations, sound, hearing), oscillations (vibrations, sound, hearing), electromagnetic fields in the environmentelectromagnetic fields in the environment
Books & Good Websites 1. http://www.physicsclassroom.com/2. http://highered.mcgraw-hill.com/sites/00724
95855/student_view0/
Books: Human Physiology: From Cells to
Systems By Lauralee Sherwood Fundamentals of Human Physiology By
Lauralee Sherwood
Good BooksBiophysicsAn Introduction to Med.
Biophysics by Prakash
Books Available at CAMP, NUSTAdvanced Biophysics by S. K.
AgarwalBasic Biophysics –For
Biologist- by M.Daniel
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
DiffusionOsmosisSurface Tension Viscosity
Membrane Transport There are two types of transport mechanisms
occurring in cells1. Active transport2. Passive transport
We will focus mainly on passive mode of transport
Passive transportMolecules that can penetrate the plasma
membrane on their own that is unassisted (without consuming cell energy) are passively driven across the membrane by two forces
1.Diffusion: down the concentration/chemical gradient
2.Conduction along an electric gradient
DiffusionMolecules are in continuous random
motion (Brownian motion)Evident mostly in liquids and gases whose
molecules are free to moveGreater the concentration of molecules
greater the likelihood of collision and movement to chamber with low concentration
Importance of diffusion
Transfer of nutrients to body cells from blood streamTransport of oxygen into cells of organs and to drive carbon dioxide out of
them e.g lungs, eyes
Importance of diffusion in eyeThe cornea is unusual in that it is transparent. The tissues
that make up the cornea are able to maintain their transparency partly by not having blood vessels flowing through them.
Without blood vessels the cornea must get it's Oxygen directly from the air. The oxygen first dissolves in the tears and then diffuses throughout the cornea to keep it healthy. Equally important, the waste product carbon dioxide diffuses out of the cornea and into the atmosphere in the reverse process
Diffusion of gases in lungsExchange of gases across the
alveolar membrane takes place due to diffusion
The blood carried to lungs is low in O2, having given up O2 to the body tissues for cellular metabolism while the air in alveolus is rich in oxygen
Because of this concentration gradient, oxygen diffuses into the blood
Similarly CO2 diffuses out of the blood into alveolus
Absorption of drugsDiffusion enables absorption of drugs across
a biological barrier (layers of cells, cell membranes etc) into the bloodstream administered through any mean except for intravenous administration
For example, transport of medicine from transdermal patch to skin and then into bloodstream occurs by passive diffusion
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