Lab Report 1: Cell Transport Mechanisms and Permeability Using Physioex 8.0
Lab Report 1: Cell Transport Mechanisms and Permeability Using PhysioEx 8.0
Introduction The purpose of these experiments is to examine the driving force behind the movement of substances across a selective or semiperpeable plasma membrane. Experiment simulations examine substances that move passively through a semipermeable membrane, and those that require active transport. Those that move passively through the membrane will do so in these simulations by facilitated diffusion and filtration. The plasma membrane’s structure is composed in such a way that it can discriminate as to which substances can pass into the cell. This enables nutrients to enter the cell, while keeping unwanted substances out. Active transport requires that the cell provide energy in the form of ATP to power the transport of substances through the membrane. During passive transport the substances move through the plasma membrane because of pressure or concentration differences between the interior and exterior of the cell. Facilitated diffusion relies on carrier proteins, and occurs when molecules are either not lipid soluble or are too large to pass through the pores of the membrane. Solutes have to combine with the carrier proteins in the membrane, and then they can be transported down the concentration gradient. Filtration is the movement of solute and water molecules across a membrane due to a pressure gradient. Active transport occurs when substances are not moving along the concentration gradient, are not lipid soluble, or are too large to pass through the membrane’s pores. The first experiment involves the facilitated diffusion of glucose. This simulation depicts the varied rates of diffusion for glucose with differing numbers of glucose carrier proteins. As the number of glucose carrier proteins increases the rate of diffusion also increases. The second experiment simulates filtration of sodium, urea, glucose, and powdered charcoal. These
Introduction The purpose of these experiments is to examine the driving force behind the movement of substances across a selective or semiperpeable plasma membrane. Experiment simulations examine substances that move passively through a semipermeable membrane, and those that require active transport. Those that move passively through the membrane will do so in these simulations by facilitated diffusion and filtration. The plasma membrane’s structure is composed in such a way that it can discriminate as to which substances can pass into the cell. This enables nutrients to enter the cell, while keeping unwanted substances out. Active transport requires that the cell provide energy in the form of ATP to power the transport of substances through the membrane. During passive transport the substances move through the plasma membrane because of pressure or concentration differences between the interior and exterior of the cell. Facilitated diffusion relies on carrier proteins, and occurs when molecules are either not lipid soluble or are too large to pass through the pores of the membrane. Solutes have to combine with the carrier proteins in the membrane, and then they can be transported down the concentration gradient. Filtration is the movement of solute and water molecules across a membrane due to a pressure gradient. Active transport occurs when substances are not moving along the concentration gradient, are not lipid soluble, or are too large to pass through the membrane’s pores. The first experiment involves the facilitated diffusion of glucose. This simulation depicts the varied rates of diffusion for glucose with differing numbers of glucose carrier proteins. As the number of glucose carrier proteins increases the rate of diffusion also increases. The second experiment simulates filtration of sodium, urea, glucose, and powdered charcoal. These
References: Marieb, Elaine N., and Susan J. Mitchell. “Cell Transport Mechanisms and Permeability: Computer Simulation.” Human Anatomy and Physiology. New York : Pearson Custom Publishing, 2009. 53-67. Print