Cell membrane

In order to determine the extent to which the reversal potential for potassium determines the resting membrane potential of a given cell, a mechanism is needed to determine the change in membrane voltage across the cell in different extracellular potassium solutions. The intracellular recording technique consists of puncturing a prepared cell with a conductive pipette. The difference in potential between the extracellular electrode and the wire in the pipette is recorded and displayed on the…

Membrane Potential in the RMP The membrane potential in the Resting Membrane Potential, or the RMP, is the little bit of voltage or electrical potential going across from the membrane of its regular resting voltage. This is caused because of gradients that make the ions go across the membrane of a cell through ion channels because ions are not soluble so they have to go through channels. These channels are called ion channels that are watery pores allowing ions to get through according to their…

Diffusion Across a Plasma Membrane Lab The purpose of this lab was to learn about the permeability of plasma membranes. In this experiment, dialysis tubing was used to simulate the semipermeable plasma membrane of a caterpillar’s intestine. Cooked starch was prepared and mixed with the enzyme amylase to simulate the mixing of the caterpillar’s saliva with a starch/leaf and then placed in the dialysis tubing to simulate the beginning of the digestive process. The enzyme amylase breaks down…

It is expected that if the concentration of sucrose increases from 0.0 M, 0.2 M, 0.4 M, 0.6 M and 0.8 M (±0.01 g) in a 40 (±0.5) mL sucrose solution, then the average percent change in mass in Solanum tuberosum core will decrease. This is because if the Solanum tuberosum cores are placed in a hypotonic sucrose solution, which is described as having lower osmolarity, than the percent change in mass of the Solanum tuberosum core will increase due to the fact that water molecules will be moving…

di- or polyvalent. Concanavalin A (a tetramer protein originally extracted from the jack-bean, Canavalia ensiformis) is a member of the legume lectin family and is a particular lectin that has been observed to be able to agglutinate a multitude of cell types, including myocytes, B-lymphocytes and fibroblasts, but for it to perform this action, it needs the presences of sugars which include mannose and glucose monomers. (Hardman and Ainsworth 1972, Loris et al. 1998). It specifically binds…

experiment is to investigate the ionic basis of the neuron’s resting membrane potential (Vm). We examine how this potential is affected by potassium ion [K+] concentration and permeability using Orconectes rusticus crayfish abdominal muscles, and we ask whether or not the Nernst Equation solely based on [K+] can also predict the cell’s resting membrane potential. We predicted that [K+] concentration had a significant influence on the membrane potential and thus the Nernst Equation was an…

Resting membrane potential is the difference in voltage of the fluids inside a cell and outside a cell and the membrane is said to be polarized. According to the book the value of the resting membrane potential varies from -40 mv to -90 mv in different types of neurons. There are two essential factors that build and generate the resting membrane potential: the differences in the ionic composition of the intracellular and extracellular fluids, and the differential permeability of the plasma…

Lab 4: Osmotic regulation of cell volume The eukaryotic organism requires homeostasis to maintain daily activities and life. Zooming into smaller units to make up an organism, cells also require homeostasis in order for the organisms to function. Understanding the different balance cells need to maintain will aid us in understanding how cells in organisms successfully maintain osmo-regulations. Eukaryotic cells have selective permeable membrane giving them the unique function of regulating…

Observing Osmosis INTRODUCTION Osmosis is the “diffusion of water across a selectively permeable membrane” (Raven et al. G-16). In this experiment, dialysis tubing was used to mimic the selectively permeable membrane to show what osmosis does when placed in different solutes. We filled dialysis tubes fill with different percentages of solute and placed them in beakers full of a different solute. Through this experiment, I saw what happens when the solution becomes hypertonic, hypotonic, and…

through the membrane due to it being too large. This is where it does not fully resemble a cell membrane because it can not transform and undergo things such as endocytosis to allow all the molecules to pass through. Conclusion This lab provided a good perspective of the movement of molecules diffusing and going through osmosis into a cell. The ability of the cell membrane to be selective was illustrated by it not allowing all the molecules through (starch). This shows how in a real cell it…