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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