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Diffusion Essay Topics & Paper Examples

Cell Transport Mechanisms

Describe two Variables that affect the rate of diffusion. The two variables that affect the rate of diffusion are: A. The size of the molecule. The larger molecule will diffuse more slowly than the smaller molecule. B. The nature of plasma membrane. If the membrane is composed of lipid portion., only lipid soluble molecules can pass through while water molecules cannot. 3. Why do you think the urea was not able to diffuse through 20 MWCO? How well did the results compare with your predictions? The urea was not able to diffuse through 20 MWCO because the size of the pores of 20 MWCO was too small to allow the large size of molecules of urea to pass through. Since,…

Diffusion and Osmosis Shown In Solutions

This lab, title Diffusion and Osmosis, was centered around the diffusion across a cellular membrane and how exactly materials move and diffuse in concentrations. Both diffusion and osmosis are forms of movement that are part of passive transport dealing with cell membranes. Diffusion is where the solutes move from an area of high concentration to a low concentration. Water goes through the cell membranes by diffusion. Osmosis is specifically the movement of water through membranes. Since osmosis and diffusion are both part of passive transport, this means that they do not require energy or pumps. There are different environments created due to diffusion. There are hypotonic, hypertonic, and isotonic environments. Hypotonic is when the solution has a lower solute concentration…

The Rate of Diffusion

Abstract I found that this experiment gives me an understanding on how osmosis and diffusion works. In its simplicity, it explains the process that our bodies (mainly cells) use all the time. It also showed me that even with the temperature changing, it doesn’t drastically change the rate of diffusion. Introduction Diffusion is important in all living systems. Osmosis is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration (Purchon 1). Diffusion is the movement of a substance from an area of high concentration to low concentration (Biological 21). With this knowledge we tried to recreate diffusion for students to understand the process. The dialysis bags represented our selectively permeable…

Gas Diffusion

OBJECTIVES: Determine the gas diffusion coefficient of acetone using the established Winkelmann’s method KEYWORDS Diffusivity, Gas Diffusion Coefficient, Winkelmann’s method OVERVIEW The knowledge of physical and chemical properties of certain materials is important because very often process engineering deal with the transformation and distribution of these materials in bulk. One such property is diffusivity. Mass transfer by diffusion takes place when there is a concentration gradient of the diffusing component. Naturally, the diffusion in gas phase is much faster than the diffusion in liquid phase due to the small spaces between the molecules that hinder other molecule movement. Other factors that will effect the diffusion are temperature, density, concentration and other external factors. 1. INTRODUCTION This experiment has been designed…

Bystander Effect

Psychology Interview Questionnaire 1. What is the bystander effect/diffusion of responsibility in your own opinion? 2. What is the Malaysian’s level of awareness towards the bystander effect? 3. How is the ‘bystander effect’ situation in Malaysia at the moment? 4. What are the factors that cause the bystander effect? 5. What triggers someone to help only after they see another person take action first? 6. Does time factor play an important role when such occurrence takes place? Will it happen only at night or during peak hours only? 7. What are the typical scenarios that can lead to the bystander effect? 8. Why are people biased when giving a helping hand, for example they would help those who are in…

Egg Lab Report

An egg is a model of a human because the egg has a cell membrane like humans do inside and outside of the body that let things pass through like water. We can use eggs to study the effect of changes in the external environment on the internal environment by having harsh environments like putting the egg in only alcohol and see what happens to the inside of the egg. Diffusion is the movement of a substance down its concentration gradient from a more to a less concentrated area. Meaning if there was more oxygen on one side of the membrane and the membrane was permeable to oxygen, the oxygen would pass through to the side of less oxygen. Osmosis…

A selectively membrane means that the cell membrane can only control over certain things

Osmosis is the diffusion of water through a selectively permeable membrane. A selectively membrane means that the cell membrane can only control over certain things that come in and out through the membrane. A membrane is just the structure surrounding the cell. Throughout osmosis, the cell could either get larger, or smaller. If the cell gets larger it means that it was put into a hypotonic solution, and result to the cell exploding. If the cell gets smaller, it means it was put in a hypotonic solution. If nothing happens to the cell, that means it was put in an isotonic solution. Once a cell starts to get smaller, it will shrivel. The difference between osmosis and diffusion is that…

Biology Diffusion Experiment

Title: What is the effect of concentration of acid on the rate of diffusion in agar blocks? Aim: To investigate how the concentration affects the rate of diffusion of hydrochloric acid through agar blocks Research Question: To determine how will different concentrations (0.1M, 0.2M, 0.3M, 0.4M, 0.5M) of hydrochloric acid affect the rate of diffusion of sodium chloride through agar blocks? Introduction-include prediction; information you have researched before Diffusion refers to the passive movement of molecules along the concentration gradient. In this case we will be looking at the diffusion of acid in agar blocks. Agar is a jelly like substance and the indicator methyl orange is added which will turn red in the presence of acid. Hence we can…

Review Sheet Results

1. Explain why increasing extracellular K+ reduces the net diffusion of K+ out of the neuron through the K+ leak channels. Your answer: Because outside a typical cell, the concentration of K+ is about 5mM and the concentration of Na+ is about 150 mM. When you increase the concentration of K+ from 5 to 25 mM and reduce concentration of Na+ from 150 to 130 mM, the outside has more concentration of K+. The membrane is permeable to a particular ion, that ion will diffuse down its concentration gradient from a region of higher concentration to a region of lower concentration. 2. Explain why increasing extracellular K+ causes the membrane potential to change to a less negative value. How well…

Agar Cubes Lab Report

Diffusion in agar cubes Introduction: All cells are dependent on a processes called diffusion, which is the movement of a substance from an area of higher concentration to an area of lower concentration. Cells need to obtain certain essential substances, like oxygen, for their survival. The rate of diffusion is said to be dependent upon the various factors: Size of molecules that have to diffuse, concentration gradient, the distance across which diffusion occurs, number of pores/openings, surface area and concentration. This rate of diffusion is measured by considering the time taken for changes to physical changes to occur. This experiment consists of using agar mixed with an indicator that changes color when places in a basic solution. It will measure…

Diffusion across a Selectively Permeable membrane

Introduction: Diffusion is movement of molecules from one area of concentration to another. This process is vital for the life functions of cells. Cells have selectively permeable membranes that allow only certain solutions to pass through them. Osmosis is a special kind of diffusion that allows water to go through semi-permeable membranes of high water potential to a region of lower water potential. Water potential measures the tendency of water to leave one place and into another. Diffusion and osmosis is responsible for the movement of molecules in and out of cells. Diffusion and osmosis can be shown using dialysis tubing which is a membrane that is made of regenerated cellulose fibers into a flat tube. When solutions that contain…

Rate of Diffusion

To test the effect of molecular weight on the rate of diffusion, various experiments were performed. One of which is the glass tube test wherein cotton balls of the same size were moistened in two different substances (NH4OH and HCl). These cotton balls were plugged at each side of a glass tube. After some time, formation of a white ring occurred. The white ring, in fact, is a product of the reaction between the molecules of ammonia (NH3) and hydrochloric acid (HCl). Results showed that NH3 which has a relatively lower molecular weight (MW NH3= 17.03 g/mol) than HCl (MW HCl= 36.46 g/mol) diffused at a faster rate (dave NH3 = 19.35 cm) compared to HCl (dave HCl= 16.18 cm)….

Simulating Dialysis

Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction? __ The molecules were to large to go through. My results matched._ 3.Describe the results of the attempts to diffuse glucose and albumin through the 200 MWCO membrane. How well did the results compare with your prediction? __The albumin was not able to go through and the glucose did. I predicted that neither of them will diffuse, however the glucose was able to go through._ ___ 4.Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea. _sodium chloride, urea, glucose and albumin__ ___ ACTIVITY 2 Simulated Facilitated Diffusion…

Effect of lipid solubility on permeability of plasma membrane

: To study the effect of lipid solubility of molecules on permeability of plasma membrane of animal cell. Introduction : Diffusion: In general, diffusion process occur when there is a concentration gradient between two region .Molecules (other than water) will move by diffusion as long as there is a concentration gradient. A concentration gradient exists when a particular type of molecule (like food coloring dye molecules) is not spread out in an even concentration, but exists in a higher concentration at some point. Discussing about the movement across the plasma membrane of cell, diffusion is the simplest type of passive transport, whereby diffusion does not require the cell to use energy. Only small molecules can cross the cell membrane by simple…

Cell Transport Mechanisms and Permeability

Exercise1 Cell Transport Mechanisms and Permeability Name ____________________________________________________________ Lab Time/Date ______________________________ Activity 1 Simulating Dialysis (Simple Diffusion) 1. Describe two variables that affect the rate of diffusion. * The size of the pores of the membrane * The size of the molecule diffusing through the membrane 2. Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction? * Because the pores of the membrane were not large enough * I predicted this correctly. 3. Describe the results of the attempts to diffuse glucose and albumin through the 200 MWCO membrane. How well did the results compare with your prediction? I predicted that only glucose would…

Cell Transport Mechanisms and Permeability

Simple Diffusion 1. The following refer to Activity 1: Simulating Dialysis (Simple Diffusion). Which solute(s) were able to pass through the 20 MWCO membrane? None of them did According to your results, which solute had the highest molecular weight? Albumin Which solute displayed the highest rate of diffusion through the 200 MWCO membrane? Na+CI Using the data from Chart 1, explain the relationship between the rate of diffusion and the size of the solute. The higher rates of diffusion occurred with a smaller weight of solute. Facilitated Diffusion 2. The following refer to Activity 2: Simulating Facilitated Diffusion. Did any of the substances travel against their concentration gradient? Explain why or why not. No, because the solutes can only move…

Physio Ex 9.0 Activity 1 Cell Transport Mechanisms and Permeability

ACTIVITY ONE- Cell Transport Mechanisms and Permeability: Simulating Dialysis (Simple Diffusion) 1. Describe two variables that affect the rate of diffusion. Molecular weight affects the rate of diffusion because the bigger the size of the molecule the longer it will take to diffuse. Membrane size is another variable that affects the rate of diffusion because if the membrane’s pores are small it will take molecules longer to diffuse though it than if the pores were larger. Also, membrane thickness is a variable because the thinner the membrane the quicker the diffusion. 2. Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction? Our prediction was…

Transport of Solute in Solvent through Osmosis

Objective: The objective is to simulate passive transport: diffusion of solutes and osmosis of water through a semipermeable membrane (dialysis tubing). The experiment will show how molecules in solution move from areas of higher concentration to areas of lower concentration in the attempt to reach homeostasis in different circumstances. Introduction: The main purpose of this lab was to observe diffusion and osmosis. This is demonstrated using dialysis tubing and a combination of monosaccharaides, disaccharides, water (H20), and sodium chlorine (NaCl), also known as table salt. We then calculated the percent change of mass over a period of time. Due to kinetic energy, cells tend to bump into one another; this is the result of the process called diffusion. Diffusion is…