Gravitation induced mechanical properties of cells
‘Load’ or ‘weight’ and ‘gravity’ works on mass. Under neutral buoyant condition, mass remains same, but weight gets reduced. Gravitational acceleration to the tune of nanometer per second square in a secluded living mass of picometer size is quite a significant force. Macromolecules having higher molar mass or density will occupy the core position of self gravitating body and intermediate or lesser will remain away from core. Movement of granular protoplasm through granular physics deserves to be understood. However, as per astrophysical principle ‘higher the mass and density- higher would be the attractive force of self gravity’ or in reverse way ‘lesser would delay the attraction”. Molar weight and density based chronological movements of macromolecules viz. nucleic acid, proteins, fats and lipids are available in cell. Nucleic acid having higher molar mass and density remain in core position, protein being intermediate over fats and lipids get distributed away from core. Ribosomes (higher molar mass) coated Rough E R may be distributed throughout the cell but its density is higher near the nucleus or near core; whereas lighter Smooth ER, not studded with ribosomes, remain away towards periphery. SER is associated with less dense fats. Mechanical living cell deformation studies have demonstrated that mechanical loads are borne by microtubules, a component of cytoskeleton (picture).
Two motor proteins viz. Kinesins moving along microtubules usually carry cargo (load) from center to its periphery and Dyneins from periphery to centre of cell. Such vectorial (directional) inward and outward movement is available in any self gravitating astrophysical body as inward gravitational pressure due to potential energy and outward kinetic energy. In biology, kinetic energy may be due to inertia plus ATP induced metabolic energy. There is thus scope for gravitation induced mechanical movement of macromolecules within cell. These are being explored for health and diseases.