Subject: BIOLOGICAL PHYSICS WITH LABORATORY (A.A. 2020/2021)
Unit Biological Physics with Laboratory
Related or Additional Studies (lesson)
Knowledge and understanding:
At the end of the course, students will gain knowledge on the kinds of forces which act in aqueous environment on molecular biological systems. They will recognize the role that those forces play in determining the structure of biopolymers and biomembranes. They will recognize the role that statistical fluctuations play in determining the functioning of two-state biosystems. They will make experience of a large number of such systems of biological origin. The student will also learn the role of mechanical properties in systems of biological interest.
Applying knowledge and understanding:
At the end of the course, students will be able to apply the learnt concepts to several biological systems.
Passing the final examination, students will be able to recognize the various types of interactions acting in various biological phenomena, will know aspects of the continuous mechanics which are relevant for systems of biological interest (cells and lipid bilayers) and will have a basic knowledge of the main experimental techniques suitable to study those interactions.
Passing the final examination, students will be able to talk about the subjects studied during the course with a suitable technical language and using a correct mathematical formalism.
The study, partially done on textbooks in English, will help students learning in an autonomous fashion and will enable them deepening further topics.
No one required. Nonetheless, knowledge of elements of classical Physics, including notions of Thermodynamics, Theory of Probability and Statistics, and that of Chemistry and structure of biopolymenrs, as derived from courses such as Chimica Fisica dei Biopolimeri are warmly recommended.
-Introduction: definition of biological system and of the concept of "life"
-Self-Assembling concepts related to lipids and lipid bilayers, "lipid raft Hypothesis
- Diffusion and Fick laws. Diffusion through a membrane, Partition coefficient. Ideal solutions and mixing entropy. Osmotic pressure and van't Hoff law
- pahse transitions in lipid bilayers. Lipid mixing. Regular solution theory and phase diagrams for lipid bilayers. Lever rule. Ternary lipid mixtures.
- Cooperative processes in biology. van't Hoff relation.
- Critical phenomena in biology. Spinodal curve and fluctuations. Law of correspondent states. Landau theory related to lipid phase transitions.
- Mechanics of lipid bilayers. Deformation modes and spring constants. Helfrich Hamiltonian. Mechanosensitive channels. Experimental measurement of lipid bilayer mechanical properties.
Thermodynamics of lipid bilayers. Fluctuations in lipid bilayers. Heat capacity vs fluctuations. Compressibility of lipid monolayers and bilayers. Bending constant of a lipid bilayer.
- Passive permeability of lipid bilayers in the absence of proteins. Force spectroscopy and dynamic force spectroscopy.
- Mechanical properties of living cells. The Atomic Force Microscope for the measurement of mechanical properties of living cells. The cytoskeleton as a polimeric matrix. Rheological properties of semiflexible polimer networks and their experimental measurement. Extracellular matrix/cells interactions.
Optical Twezzers for the study of protein folding
Lab experiences on:
Measurement of mechanical properties of lipid bilayers
Measurement of the critical temperature of lipid monolayers
Unfolding of single proteins by Optical Tweezers
Frontal lectures together with a lab experience All the lectures will be available on line Meet the professor: thursday from 2 pm to 4 pm otherwise, by appointment established by e-mail
Oral examination together with a written report about the lab experience
The study, partially done on textbooks in English, will help students learning in an autonomous way and will enable them deepening further topics related to physical aspects of systems of biological relevance.
-Meyer B. Jackson, Molecular and Cellular Biophysics, Cambridge University Press, (2010).
-Jacob N. Israelachvili, Intermolecular and Surface Forces, Academic Press, (2010).
- Ken Dill, Sarina, Bromberg Molecular Driving Forces, Garland Science (2010)
- Rob Phillips, Jane Kondev, Julie Theriot, Hernan Garcia, Physical Biology of the Cell Garland Science (2012)