Haven't found the Essay You Want?
GET YOUR CUSTOM ESSAY SAMPLE
For Only $12.90/page

Membrane Essay Topics & Paper Examples

Osmosis and Selectively Permeable Membrane

Introduction: Molecules have kinetic energy. This causes the molecules of the cell to move around and bump into each other. Osmosis is a special kind of diffusion where water moves through a selectively permeable membrane (a membrane that only allows certain molecules to diffuse though). Diffusion or osmosis occurs until dynamic equilibrium has been reached. This is the point where the concentrations in both areas are equal and no net movement will occur from one area to another ( Reece, J. B, 2011, pp. 132-134). Background: 1. Water potential is predicting the movement of water into or out of plant cells. Water always moves from an area of high to low water potential. 2. When the two solutions on either…

Action Potential and Receptor Olfactory Receptor

You scored 100% by answering 4 out of 4 questions correctly. 1. A very intense stimulus can sometimes stimulate sensory neurons that have evolved for a different modality. Thus, with a blow to the eye, one “sees stars. ” In this example the photoreceptors in the eye are responding to You correctly answered: c. intense pressure. 2. Olfactory receptor neurons respond to low concentrations of chemical odorants because there are membrane proteins in the receptor ending of this sensory neuron that You correctly answered: b. can bind and respond to the specific odorant. 3. The sequence of events starting with a sensory stimulus and ending with a change in membrane potential is called You correctly answered: c. sensory transduction. 4….

Action Potential and Receptor Olfactory Receptor

You scored 100% by answering 4 out of 4 questions correctly. 1. Assuming that the resting potential of a sensory neuron is -70 mV, which of the following represents a depolarization? You correctly answered: c. a change to -60 mV 2. Which of the following is a sensory modality (type of sense)? You correctly answered: e. all of the above 3. Which of the following is a sensory stimulus? You correctly answered: d. all of the above 4. Which of the following is true of the response of a sensory neuron to the appropriate sensory stimulus? You correctly answered: c. both a and b 010/27/13 page 1 Experiment Results Predict Question: Predict Question 1: The adequate stimulus for a Pacinian…

The effects of osmosis

Introduction: Osmosis is a movement of water across a semi-permeable membrane. This may only happen when there is a difference in concentration between the two sides of the membrane. The water moves from low concentrations to high concentrations. That is because the low concentrated area tries to dilute the opposite via osmosis. The effects osmosis has on a cell are either that it becomes turgid and hard as water enters the cell or it becomes dehydrated (this is called plasmolysing in plant cells) as water leaves the cell and the solution enters. There is a change of mass, volume, texture and length. Aim: The aim is to investigate the effects of varying concentrations of a salt solution on the amount…

The effect of alcohol concentration on the cell membrane

Abstract: In this experiment I found out that as the concentration of the alcohol was increased so did the colour intensity of the solution. This is because the higher concentration of ethanol, results in more damage done to the cell membrane, resulting in leakage of red pigment from the cell. If the membrane is damaged more, more red pigment will leak out of the membrane and into the ethanol. Hypothesis: The higher the concentration of ethanol the more permeable the cell membrane will become. Introduction: The cell membrane is a thin semi permeable membrane which surrounds the cytoplasm of the cell. The cell membrane controls whatever enters and leaves the cell. All animal and plant cells have cell membranes. Phospholipids-…

Origin of Rice

A major component of plants that are starchy in nature, the amyloplast are organelles that store starch. They are classified as plastids, and are also known as starch grains. They are responsible for the conversion of starch into sugar, that gives the starchy plants and tubers energy. Function: Synthesis and storage of starch granules Cell Membrane or Plasma Membrane The cell membrane is a thin layer made up of proteins, lipids, and fats. It forms a protective wall around the organelles contained within the cell. It is selectively permeable and thus, regulates the transportation of materials needed for the survival of the organelles of the cell. Function: Protects the cell from surrounding Cell Wall Unique to plant cells, the cell…

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…