The Effect of Cholesterol on Membrane Fluidity Essay

This experiment gave a visual understanding of osmosis and diffusion. The first experiment proved that solutes would move down a concentration gradient if permeable to the selective membrane. The second experiment proved different solute concentrations affect the movement of water, depending on the solute concentration inside the cell. The purpose of this lab was to look for different solutes that can cross an artificial membrane and to observe the effect of different concentrations of sucrose on the mass of a potato cell. Results for Part One suggested that the molecular weight of albumin and starch was too large to

In this lab experiment, half our group observed and measured osmosis using dialysis tubes that were represented as the semipermeable membrane. It is permeable to water and other small molecules but is impermeable to larger molecules such as the sucrose solution used in each of the four beakers and tubing. The other half of our group observed the tonicity of sheep blood to determine whether the blood was isotonic, hypotonic, or hypertonic. The 85 g/dL of NaCl solution was the ideal isotonic number in relation to the sheep blood cells as well as a reference to the other observations of the solutions.

In all living organisms, water and nutrients make their way to tissues and cells because of osmosis, which for all intents and purposes is essential to the survival of cells (Rao & Kaur, 2007). Besides, cells and by extension organisms also get rid of their waste products by osmosis. In animals, for instance, this process occurs in renal tubules (kidneys) that filter and clean the blood to get rid of toxic metabolites and other chemicals. In order to understand how cells acquire and get of nutrients, it is imperative to know how osmosis operates. The objective of this experiment is, therefore, to study six decalcified eggs to understand and demonstrate the process of osmosis between the inside of the egg’s membrane and multiple environments of water/solute (solutions) of different concentrations: deionized water, 20% sucrose, and 40% sucrose.

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

Repeated Trials: In procedure one, we tested diffusion on different sized cell models (gelatin with various volume and surface area wise). In procedure two, we tested cell models in different internal environments and similar external environments to find the effects on rate of osmosis. In procedure three, we used potato cells in different concentrated sucrose environments to test the effects on water potential on cells and osmosis.

The Transport of Substances Across the Plasma Membrane The plasma membrane or, the cell surface membrane, is made almost entirely of protein and lipid. The plasma membrane controls the movement of substances into and out of a cell. It is partially permeable so some substances cross more easily than others.

Membrane fluidity is important for the normal functioning of a cell as it ensures free rotation and movement of proteins and lipids within the bilayers, certain limits must be maintained for correct functioning.

Our body naturally produces cholesterol through the liver, we can also obtain cholesterol from consumed products. We need small amounts of cholesterol to produce hormones, bile, and vitamin D. Cholesterol doesn’t dissolve in the bloodstream once it is inside the body. It needs to be carried by two types of lipoproteins called low density lipoproteins(LDL) and high density lipoproteins(HDL). The more cholesterol we consume, the more LDL and HDL we produce. HDL is

In order to study the transfer of liquid across the plasma membrane, in this experiment a de-mineralized egg was examined. Upon receiving the eggs they had already previously been soaked in a vinegar solution for several days, dissolving the eggs shells thus leaving a thin semi-permeable membrane exposed, which is representative of the cells in our bodies.

Voltage gated channels are necessary components of life processes, in many organisms. One in particular, is the calcium voltage gated ion channel. Often lodged within the phospholipid bilayer, the imbalance of the calcium, or, the inside vs outside concentration, creates a gradient. The channel proteins often undergo conformations, states that which allow or block calcium ions from passing through. As ions move inside the cell, this creates a depolarization, or surge in the voltage. Clinically, this is associated with the heart and how it allows the heart to contract, which can be read in the

Diet rich in cholesterol. When there is a high level of cholesterol in the bile juice, and a reduced amount of bile salts and lecithin,

Cholesterol is a lipid that helps manufacture vitamin D on the surface of the skin, produces hormones, maintains cell membranes, and possibly helps cell connections in the brain.3 Based on what is known about calcium transporting throughout the body we can infer that cholesterol also has a similar process. When there is an imbalance of cholesterol homeostasis we can have high density lipoprotein (HDL) which is known as good cholesterol, or low-density lipoproteins (LDL) which is known as bad cholesterol. Lipoproteins differ in size, shape, composition, function, and contribute to vascular

To maintain homeostasis, cells must move materials in and out of their cell membranes. The cell membranes are semi-permeable, which helps to regulate what enters and leaves the cell. Phospholipid fatty acids are hydrophobic, meaning they dislike water and help to limit the movement of water across the membrane. The membrane is actually a phospholipid bilayer containing embedded proteins.

The purpose of this experiment was to determine the effects of tonicity on a cell membrane using red blood cells, potato strips and three unknown solutions (A, B, C). First three slides were prepared containing RBC’s and unknown solutions A, B and C. A control slide was prepared only using RBC’s. After observing each slide under the microscope it was determined that unknown solution A was hypertonic because the RBC appeared to have shrunk. The RBC in unknown solution B appeared to be swollen, therefor, the tonicity of unknown solution B was hypotonic. Unknown solution C showed no change to the RBC shape, it was suggested that unknown solution C was isotonic. To confirm the tonicity

are covalently attached to the surface of the membrane are loosely associated with the surface of the membrane may penetrate the membrane partially never interact with the surface of the membrane All of the following can cross the cell membrane by simple diffusion EXCEPT? O2 ethanol CO2 glucose All of the following factors affect membrane fluidity EXCEPT? temperature cholesterol cis/trans-configuration of double bonds all of the above affect membrane fluidity Which of the following is true when comparing facilitated diffusion to simple diffusion? facilitated diffusion does not occur down a concentration gradient, only simple diffusion does facilitated diffusion is faster than simple diffusion energy in facilitated diffusion is supplied