Transmembrane Movement Lab Report

ABSTRACT

Transmembrane movements are substantially necessary for cellular level functions in all entities. Understanding a part of this, membrane and passive transport was the study that was conducted during the experimentation. Three types of experiments were completed in order to demonstrate the characteristics of membranes and factors affecting the passive transport in cells. Larger molecules are too large to cross the partially permeable membrane was the result of the first experiment. Second, was ascertained the contribution of solute concentration in osmotic flow and the last experiment evidenced that the lesser the molecular weight higher the diffusion. Thus, passive transport is influenced by the size of the molecules, solute concentration

Cell membrane, a semi-permeable structure consists of a lipid bilayer and membrane proteins, which facilitates the transmembrane movement (Campbell et al. 2008). Substances are moving across the hydrophobic region of lipid bilayer using membrane proteins, which regulates the movement of particular substances. Thus, there are two major types of membrane proteins, carrier proteins and channel proteins (Rees et al. 1989). Carrier proteins hold on their substances and shuttles them across the membrane by changing the shape and channel proteins acts as a hydrophilic channel in the hydrophobic area of bilayer and helps the molecules to travel through. Accordingly, the factors that affect the transmembrane movement are solute concentration, temperature, pH, enzymes, transmembrane substances and surface area of the solution ([OSC] 2013).

Further, there are two types of transport across a membrane: active transport and passive transport. Active transport is the movement of solutes against the gradient using energy and passive transport is movement of substances across the gradient without any work done (Campbell et al. 2008). Thus, passive movement is spontaneous without any energy

Entering of water into the cell from the environment is influenced by solute concentration, thus the tonicity of the placement of the cell as well as the presence of partially permeable membrane (Campbell 2008). So, the solute concentration in the cell will increase the flow of water into the cell because of osmotic gradient. Therefore, in the beginning of this experiment, it was assumed that the water would be diffused into the raw potato with salt and other potatoes would be stay same as was in the beginning.

3. Experiment C: Molecular weight and rate of diffusion

This experiment was aimed to understand the relation between the molecular weight of a compound and its diffusing ability. The rate of diffusion can be determined using the molecular weight of the compound (Meyertholen 2015). So, the rate of diffusion is inversely proportional to the molecular weight of the particle. That is, a smaller weight particle will diffuse faster than a larger one. Hence, the hypothesis of this experiment was potassium permanganate would diffuse more than the methylene blue because of its less molecular weight.

MATERIALS AND