Date of Award:

5-1-1969

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Department name when degree awarded

Physiology

Committee Chair(s)

Raymond T. Sanders

Committee

Raymond T. Sanders

Abstract

From the general theory of irreversible thermodynamics, equations were developed describing transport across natural membranes. The formulation established the criterion of irreversibility and illustrated the origin of the linear thermodynamic rate equations. With the assumptions of local equilibrium and the steady state, transport equations were formulated in terms of membrane parameters that are accessible to measurement. Experiments to determine these parameters were performed on the cells of the fresh water algae Nitella clavata. Values for the membrane conductance, the ionic transference numbers for Na, K and Cl, the membrane potentials and the contribution of active transport are reported. This is the first report of such determinations of transference numbers for the Nitella membrane and permit calculation, based upon irreversible thermodynamics, of the resting membrane potential, membrane conductance and ionic conductivities. The agreement among the measured membrane parameters, the calculated parameters and previously published values was excellent and illustrated inadequacies of the classical approach to these parameters. A treatment of the Nitella transport system as a series array of membranes, rather than a single membrane, indicated how linear non-equilibrium thermodynamics will allow the prediction of non-linear membrane behavior. A double membrane system was constructed with values of the membrane parameters selected to represent closely the natural values. The current-voltage relationship for this system was then derived and plotted. The consequent resting membrane potential and resistance, and the potential at E = 0 all agreed well with the values found in the literature.

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