solutions separated by a membrane. The terms are different because osmolarity takes into account the total concentration of penetrating solutes and non-penetrating solutes‚ whereas tonicity takes into account the total concentration of only non-penetrating solutes.[2] Penetrating solutes can diffuse through the cell membrane‚ causing momentary changes in cell volume as the solutes "pull" water molecules with them. Non-penetrating solutes cannot cross the cell membrane‚ and therefore osmosis of
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Extended experimental investigation: effects on membranes of environmental stress Background It is not possible to observe membranes directly‚ so this investigation is an indirect study of the effects of different substances and treatments on living beetroot cells. Beetroot cells have been chosen for this activity because each beetroot cell has a large central vacuole bounded by a membrane (Figure 1). Contained in the vacuole is the red pigment anthocyanin‚ which gives the beetroot its
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The Biological Importance of Lipids Lipids are organic compounds found in all types of plant and animal cells. They always contain carbon‚ hydrogen and oxygen‚ however the relative amount of oxygen is less than the amount of carbohydrates in lipids. Lipids are polymers and the long chains of repeating units are joined together in a condensation reaction where water is also produced. The most common types of lipids are triglycerides‚ phospholipids and waxes. Triglycerides are formed by three fatty
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In this lab we will look at how molecules move across the membrane of a cell . Osmosis is the movement of water across a cell membrane.In osmosis the cell membrane is selectively permeable‚which allows for the membrane to control what types of substances that passes through.Transportation can either be passive or active.Passive transport does not require the use of added energy where as active transport requires the cell to use energy. Diffusion is the simplest form of passive transport. Using
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Gabriela Rios-Martinez March 1‚ 2014 BIO 141 Exam 1 Study Questions Chapter 1: Biology and the Tree of Life (#1 – 4) 1. What is the difference between a hypothesis and a scientific Theory? Between a hypothesis and a prediction? What kinds of hypotheses are useful for scientific investigations that try to explain the natural world‚ and which are not? Give one or more examples of hypotheses that are and are not scientifically useful. (a.) A scientific theory has two components; a pattern
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Molecules Across Cellular Membrane Abstract: Cell membranes play an important role in regulating what goes in and out of the cell. Diffusion‚ the process of movement of substances across the cell membrane from higher concentrations to areas of lower concentration‚ plays an active role in the transport and the regulation through cellular membrane. Sometimes‚ there are cases when cells are placed in hypotonic solutions and substances will diffuse through the cell membrane too much and will result the
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cells and platelet cells: A review. Retrieved March 27‚ 2017‚ from http://www.ghrnet.org/index.php/JT/article/view/1340/1795 Materials Research Society‚ 35(5)‚ 382–388.Web. 8 Mar. 2017.Web. 26 Mar. 2017. Kimball‚ John W. "Transport Across Cell Membranes." Kimball’s Biology Pages. N.p.‚ 17 Apr. 2014. Web. 8 Mar. 2017. R. I. Macey‚ Transport of water and urea in red blood cells American Journal of Physiology - Cell Physiology Mar 1984‚ 246 (3)C195-C203;Web. 26 Mar.
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the water potential outside the cell to be lower than that inside the cell. When placed in a hypertonic environment‚ the gradient in animal and plant cells are reversed and water exits the cell. This sudden release of water results in a shrinking membrane‚ called crenation‚ which
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to investigate and understand the affect different temperatures have on cell membrane structures. Hypothesis The higher the temperature is‚ the higher the rate of absorbance of the cell membrane will be. Variables Controlled Variables | Independent Variables | Dependent Variables | The length of the beetroot placed into the test tube. | The temperature of the water bath. | The absorbance of the cell membrane of the beetroot. | Time placed into the hot water bath after the beetroot was
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the movement of osmosis through a selectively permeable membrane‚ in this case potato. Introduction: Osmosis is the movement of water through a semi permeable membrane‚ separating solutions of different concentrations. The water passes from a region of high concentration to a region of low concentration‚ until the two concentrations are equal in concentrations of water. Many cell membranes behave as semi permeable membranes‚ and osmosis is a vital mechanism in the transport of fluids
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