Topic 2 – Cell membranes Reading Chapter 5 Objectives Functions of cell membranes The fluid mosaic model The lipid bilayer – phospholipids‚ glycolipids and sterols Properties of the lipid bilayer Membrane proteins – the ‘mosaic’ in the model Solute movements across membranes BIO 1140 – SLIDE 1 http://www.nikonsmallworld.com/gallery/year/2006/id/751 Functions of cell membranes – an overview Fluid mosaic model Singer & Nicolson 1972 Fluid lipid molecules in which
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Cell Membrane Structure Phospholipids are arranged in to layers‚ called the bilayer. They only have 2 fatty acids‚ this is because the third fatty acid is replaced by a negatively charged phosphate group. The phosphate heads are polar‚ in other words attracted to water‚ therefore they are hydrophilic. The lipid tails are non-popular as they’re not attracted to water and therefore known as hydrophobic. When phospholipids are added to the water‚ they rearrange themselves so that the hydrophilic heads
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Cell Membrane The Cell Membrane- The cell membrane is a semi-permeable membrane that surrounds the cytoplasm of a cell; the cell membrane is made up of phospholipids‚ proteins and carbohydrates. Its function is to protect the integrity of the interior of the cell allowing certain substances into the cell‚ while keeping other substances out. The phospholipids form a thin‚ flexible sheet while the proteins float in the phospholipid sheet like an ice berg‚ and the carbohydrates extend out from the
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Cell Membrane Transport The purposes for these experiments is to be able to understand osmosis and its relationship to tonicity of solutions‚ and the transportation of molecules across cell membranes. It’s also used to understand‚ and how temperature affects diffusion. You also learn how to test for presences of starches and sugars in solutions. In the first exercise I will be testing for diffusion through an artificial membranes. This one has forty five steps to it. I will not go into
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’direct ’ passage in and out of the plasma membrane ( Lacerda L.2011) Allowing some molecules enter and exit the cell membrane‚ to create a balance in concentration inside and outside of the cell‚ by doing so the cell often become hypotonic‚ where the concentration outside the cell is higher than the concentration inside the cell‚ therefore causing the swelling of that cell. When cell was placed the the deionized water environment‚ hypothesis was made that the cell will become hypotonic and swell up as
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All living cells have a cell membrane and it is probably the most important organelle of a cell. The cell membrane is composed of a phospholipid‚ proteins and carbohydrates. The phospholipids are arranged in a bilayer with the hydrophilic ends facing out and the hydrophobic ends facing the inside of bilayer. Membranes can contain phospholipids with different fatty acids which affects the strength and flexibility of the membrane. There are two different proteins in cell membranes. One is a protein
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Experiment 2 The Cell Membrane Abstract The boundary between any cell and its environment is the plasma membrane‚ composed of a matrix of phospholipid molecules along with a number of different kinds of proteins. Membranes have different properties and a variety of functions‚ in large part determined by the specific proteins within the membrane. This experiment is designed to determine the stress that various factors‚ such as osmotic balance‚ detergents and pH‚ have on biological membranes. There are
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2. Draw and completely label a cell membrane. [pic] 4. List and briefly discuss the 5 components of cellular membranes. 1. Phospholipids layer- 2 layers ‚ polar and non polar ‚ polar facing the extracellular fluid and cytoplasm 2. Transmembrane proteins-integral membrane proteins are proteins that expand the membrane 3. Interior protein network-peripheral proteins are in the interior side of the membrane 4. Cell surface markers are glycolipids‚ carbohydrates/lipid
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The Cell membrane surrounds all living cells and is the most important organelle‚ there is also a similar plasma membrane that surrounds all the organelles except for the ribosome. The membrane controls how and what substances can move in and out of the cell/organelle The structure of the membrane is often referred to as the “Fluid Mosaic Model”; this is because of the way it is structured It is composed of phospholipids‚ proteins‚ and carbohydrates‚ which are arranged in a fluid
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Title: The effect on temperature on beet cell membranes. Introduction A cell membrane or plasma membrane is very important in protecting cells. A cell membrane is a thin layer that protects the cells. The membrane is filled with lipids and proteins. The cell membrane protects the cell from ions and molecules that enter and exit the cells. I hypothesize that at -5 degrees Celsius‚ the color intensity will be a 1. I hypothesize that at 5 degrees Celsius‚ the color intensity will be a 2
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fluid mosaic model of the cell membrane. What is the fluid mosaic model? The fluid mosaic model is a model conceived by S.J. Singer and Garth Nicolson in 1972 to describe the structural features of biological membranes. The membrane is described to be fluid because of its hydrophobic integral components such as lipids and membrane proteins that move laterally or sideways throughout the membrane. That means the membrane is not solid‚ but more like a ’fluid’. The membrane is depicted as mosaic because
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Planning Aim In this experiment I will be testing the effect of temperature on the plasma membrane of a beetroot. I will do this by measuring the percentage light transmission using a spectrophotometer. Once I have obtained my results‚ I will justify them using scientific knowledge explaining what I have observed whilst carrying out the experiment. Factors to be controlled "« The pH concentration "« Regular use of distilled water "« Ensuring that the surface area of each piece of beetroot is
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of the plasma membrane found within and around all cells’ The plasma membrane surrounds all eukaryotic and prokaryotic cells. Eukaryotic cells have membrane bounded organelles whereas prokaryotic cells do not. The plasma membrane forms the boundary between the cell cytoplasm and the environment. Its function are to allow different environments to be established inside and outside the cell. It also controls the movement of substances into and out of the cell. The cell surface membrane which surrounds
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on the permeability of cell membranes Introduction For my coursework‚ I intend to assess how temperature affects the plasma membrane of a cell. For this I will use the cell of a beetroot. Background What is a cell membrane? The cell membrane‚ also called the plasma membrane is a semipermeable lipid bilayer which is the surface of all cells that surrounds the cytoplasm. The membrane is called a bilayer as it has a double layer of phospholipids. Within the cell membrane there are many biological
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8 themes of biology relating to the cell membrane Science as a process: Science is a process which encompasses many methods in order to reach a final conclusion. This relates to the cell membrane because it carries out many processes to reach a final product. For example‚ the cell membrane forms a barrier between the inside of the cell and the outside‚ so that the chemical environments on the two sides can be different. The cell controls those differences to optimize the working of the organelles
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variation in temperature on the permeability of cell membranes using fresh beetroot Aims In this investigation‚ you will subject fresh‚ washed beetroot discs to different temperatures to investigate the effect of temperature on the permeability of the plasma membrane. Overview The beetroot discs will be placed in distilled water at different temperatures. You will compare the intensity of the beetroot pigment that has leaked out from the cells subjectively and possibly objectively using a colorimeter
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permeability of the cell membrane. Introduction Located within the vacuole of beetroot cells is a red pigment call Betalains. Typically these pigments are contained within the cell vacuole by the tonoplast (vacuole membrane)‚ however When beetroot is heated these red pigments escape the vacuole. This experiment aims to explore the effect of temperature on the permeability of the cell membranes (i.e. Tonoplast). ‘The cell surface membrane is the plasma membrane that surrounds cells and forms the
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Cell Membrane Transport Cell Membrane Transport Hands-On Labs‚ Inc. Version 42-0034-00-01 Lab Report Assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a su Premium 609 Words 3 Pages Diffusion and Osmosis of Solutes and Water Across a Membrane Diffusion and Osmosis of Solutes and Water Across a Membrane Brittany Bacallao Nova Southeastern University Abstract: This experiment gave a visual understanding
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Assignment 1: Cell Membranes and Temperature Background Theory Beetroot contains betalain pigments within it’s vacuole‚ which gives it it’s purple-red colour‚ it’s this pigment which leaks out as the beetroot is heated and the cells membrane begins to break down. The practicals aim is to show the effect of temperature on the cell membrane by observing the colour change of the water the beetroot was placed in. The cell membrane is important as it controls the substances enters and leaves the cell with
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Outline the roles of membrane at the surface of the cell The plasma membrane encloses the cell‚ defines it boundaries and maintains the essential differences between the cytosol and the extra-cellular environment. The separation of the internal and external environment maintains a constant internal environment which is essential for the cell to function efficiently. Membrane receptors can interact with specific molecules corresponding to stimuli such as hormones to generate a signal cascade which
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