Wannabees and also Odd Girl Out‚ discusses two of these divisions. She labels the first group the "alpha" group; these are the girls that are considered "popular‚" who wear the trendy clothes‚ and are beautiful and wealthy. The second group she calls "beta‚" and these are the girls who are "outside the box" - they long to be invited to the parties‚ and try everything to fit in. Susannah Meadows‚ author of the June 3‚ 2002 cover story of Newsweek entitled‚ "Meet the Gamma Girls‚" breaks open a third group
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At rest‚ a nerve cell maintains a difference in charge between the inside and the outside of the cell membrane. This difference in charge is continued by three factors. Firstly‚ in the cell membrane‚ there are sodium potassium ‘pumps’ crossing the membrane which are proteins that bring 2 potassium ions into the cell‚ for every 3 sodium ions it pumps out. As well as this‚ there are protein channels which allow potassium ions in the cell to flow out via facilitated diffusion. Potassium diffuses out
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TRANSPORT ACROSS MEMBRANE define diffusion and describe its role in nutrient uptake and gaseous exchange in plants and humans define osmosis and describe the effects of osmosis on plant and animal tissues define active transport and discuss its importance as an energy-consuming process by which substances are transported against a concentration gradient‚ as in ion uptake by root hairs and uptake of glucose by cells in the villi . A cell is surrounded by a layer of cell surface membrane. This phospholipid
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The effect of temperature on the cell membranes of beetroot cells and amount of pigment released. Apparatus • Corer size 4 • White tile • A Beetroot • Automatic Water Bath • Segregated knife • A thermometer • Stopwatch Method: • First take the white tile and the corer. Then collect a cylinder of beetroot by pushing the corer into the beetroot and withdrawing it. The cylinder remains inside the corer- so push it out with the end of a pencil. • Collect 3 cylinders
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Activity 6.2-Membranes Organize a Cell’s Activity Dissect a Plasma Membrane Objective: to understand the structure of a membrane 1. Why is the membrane described as a phospholipid bilayer? It is described as a phospholipid bilayer because there are two layers of phospholipid molecules. 2. How does the arrangement of the phospholipids form a bilayer? The phospholipids arranged in two layers so that the charged phosphate heads interact with the water on either side of the membrane‚ and the
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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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Simple Diffusion Activity 1: Simulating Simple diffusion 1. What is the molecular weight of Na+? 22.99 2. What is the molecular weight of Cl-? 35.45 3. Which MWCO dialysis membranes allowed both of these ions through? 50‚ 100‚ and 200 4. Which materials diffused from the left beaker to the right beaker? NaCl‚ Urea‚ and Glucose at MWCO 200 5. Which did not? Why? Albumin‚ too large to diffuse Activity 2: Simulating Dialysis 1. What happens to the urea concentration in the left beaker
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1a. Aquaporins are membrane proteins that have fourteen various structures however the most common form is that of a homotetramer. The homotetramer is often found in the membrane and composed of four aquaporin membranes. The structural arrangement creates a fifth channel in the middle that allows for gas transportation. 1b. The direction of H2O molecular flow through a channel is determined by an osmotic gradient. 1c. One of the mechanisms that prevents proton channeling is due to the (ar/R) and
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respiration. In the presence of oxygen‚ pyruvate or fatty acids‚ can be further oxidized in the mitochondria. Each mitochondrion is enclosed by two membranes separated by an intermembrane space. The intermembrane space extends into the folds of the inner membrane called cristae which dramatically increase the surface area of the inner membrane. Cristae extend into a dense material called the matrix‚ an area which contains RNA‚ DNA‚ proteins‚ ribosomes and range of solutes. This is similar to
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Plasma membranes are selectively permeable. The purpose of this experiment is to reveal how a form of diffusion in a semipermeable membrane works by creating a real life simulation of a semipermeable plasma membrane. This is done by building an imitation of a caterpillar’s digestive tract using dialysis tubing and glassware. The first material in this experiment is a small beaker representing the head and crop of the caterpillar. This beaker is filled with both starch and the enzyme α-amylase. This
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