SCIE1106 LABREPORT
Cell Osmotic Fragility, Solute Permeability and Diffusion Potentials of Permeable Membranes
Introduction
This experiment examines cell membrane permeability, osmosis and membrane voltages; all of which are important in understanding how cells are affected by their environment. The movement of water across membranes is important for cell volume and thus the volume of extracellular compartments. The mechanisms for solute transport are essential in maintaining cell functions and homeostasis. Furthermore, ion transport across membranes generates membrane voltages, which are important in maintaining osmotic balance.
Previous related experiments have been conducted, for example de Wit and van Gastel (1969) investigated the relationships between cell age and osmotic fragility. Their findings concluded that younger cells are more resistant to lysis and older cells were comparatively more susceptible to immune haemolysis. Naccache and Sha’afi’ (1973) found that cell structure was a predominant factor in a cell’s permeability to solutes.
Part 1 sought to measure the movement of water in response the addition of various concentrations of NaCl. It was hypothesised that as the concentration of NaCl increases, then the amount of lysis of the red blood cells would decrease. Part 2 aimed to determine how permeable red blood cell membranes were to various solutes. It was hypothesised that as the lipid solubility of solutes (Kether) increases, as does the permeability coefficient. Part 3 of the experiment aimed to produce and measure diffusion potentials across two different membranes of semi-permeability. It was hypothesised that as the voltage increases, as does the log of the concentration gradient.
Method
Methods for Part 1 and Part 2 were performed as described in the SCIE1106 Lab Manual (3).
Small changes were made in Part 3 of the experiment.
Data was processed through Microsoft Excel.
Results
Various colours and stages of cell lysis was observed in Part 1. The 3
Introduction
This experiment examines cell membrane permeability, osmosis and membrane voltages; all of which are important in understanding how cells are affected by their environment. The movement of water across membranes is important for cell volume and thus the volume of extracellular compartments. The mechanisms for solute transport are essential in maintaining cell functions and homeostasis. Furthermore, ion transport across membranes generates membrane voltages, which are important in maintaining osmotic balance.
Previous related experiments have been conducted, for example de Wit and van Gastel (1969) investigated the relationships between cell age and osmotic fragility. Their findings concluded that younger cells are more resistant to lysis and older cells were comparatively more susceptible to immune haemolysis. Naccache and Sha’afi’ (1973) found that cell structure was a predominant factor in a cell’s permeability to solutes.
Part 1 sought to measure the movement of water in response the addition of various concentrations of NaCl. It was hypothesised that as the concentration of NaCl increases, then the amount of lysis of the red blood cells would decrease. Part 2 aimed to determine how permeable red blood cell membranes were to various solutes. It was hypothesised that as the lipid solubility of solutes (Kether) increases, as does the permeability coefficient. Part 3 of the experiment aimed to produce and measure diffusion potentials across two different membranes of semi-permeability. It was hypothesised that as the voltage increases, as does the log of the concentration gradient.
Method
Methods for Part 1 and Part 2 were performed as described in the SCIE1106 Lab Manual (3).
Small changes were made in Part 3 of the experiment.
Data was processed through Microsoft Excel.
Results
Various colours and stages of cell lysis was observed in Part 1. The 3
References: Alberts, B., Johnson,A., Lewis, J., Raff, M., Roberts, K., and Walker, P. (2008) Molecular Biology of the Cell 5th ed. (New York, Garland Science). Beilharz, M. (2014) Molecular Biology of the Cell 106 (SCIE1106) Unit Manual Semester 2 (The University of Australia, Australia). Dudok de Wit, C. and van Gastel, C. (1969). Red Cell Age and Susceptibility to Immune Haemolysis. Scandinavian Journal of Haematology 6, 373-376 Naccache, P., and Sha’afi, R.I. (1973). Patterns of nonelectrolyte permeability in human red blood cell membrane. He Journal of General Physiology 62, 714-736