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For a cells metabolism to take place, an internal environment has to be maintained.

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Introduction

Abstract For a cells metabolism to take place, an internal environment has to be maintained. Without this internal environment, a cell would cease to live. The plasma membrane surrounds a cell defining the point where the outside world is kept from the inside. This plasma membrane regulates the passage of materials such as molecules, ions, salts, and enzymes to and from the cell. Through years of cell research, biologists have been able to recognize that a cell membrane is not stagnant barrier of separation but is an interactive complex that plays just as important of a role of the cells procedures as the organelles themselves within the cell. Such an intricate role of cell membranes means that they have to be maintained properly. If this biological membrane were to be breached or denatured by external factors, the homeostasis and metabolism within the cell would cease to exist. To see if thermal energy does fracture a cell membrane, heat was applied to beat extractions in water to see if the red pigment betacyanin was released which exists within the beet. Results of the tests were just as expected. At higher applied temperatures the beet extractions released much more betacyanin because of their fractured membranes. At 100 � C Absorbance was greater than 2.0 on the photospectrometer. At lower temperatures ( x < 20 � C ) ...read more.

Middle

Heat stress is a constraint in grain filling stages of the wheat in West Asia, Australia, North Africa and central and southern Great Plains of the U.S. (Ibrahim et al. 2001). In wheat, the rise in temperature disrupts solute movement of ions, water and organic molecules. When this disruption occurs, photosynthesis and respiration is altered. Using the Membrane thermal stability test (MTS), researchers were able to determine electrolyte leakage of leaves which were subjected to rises in temperature (Ibrahim et al. 2001). This study involved six wheat genotypes. The journal article "Heritability of Heat Tolerance in Winter and Spring Wheat," proposed by Amir Ibrahim and James Quick, was directed toward measuring the increased electrolyte diffusion stressed tissue in deionized water and quantified by electrical conductance. Reynolds (1994) obtained positive correclations between MTS values and wheat grain yield in five internations locations with high temperatures during production season (Ibrahim et al. 2001). Another study run by Kenneth B. Marcum was to determine if differences in cell membrane thermostability exist among cultivars of Kentucky bluegrass. A cultivar can be defined as a race or variety of a plant that has been created or selected intentionally and maintained through cultivation. By knowing the cell membrane thermostability they could predict whole plant heat tolerance of these cultivars (Marcum 1998). CMT was determined by subjecting leaf segments to progressive heat shock exposure times, and deriving cellular electrolyte leakage curves (Marcum 1998). ...read more.

Conclusion

If we had kept the beet cell in a freezing environment for a longer period of time, the membrane of the beet cell would have frozen, and ice crystals that would have formed in the water probably would have punctured the cells releasing the betacyanin pigment. If betacyanin were to leak out of the beet and directly be exposed to higher water temperatures it could break down and dissolve. This would alter the results because the photospectrometer is supposed to measure how much of the pigment is in the solution. For this reason, the second experiment we performed was a direct test on the pigment betacyanin. If ideal results came about, we would see the betacyanin pigment start to gradually denature which means absorbance values would decrease. This is exactly what happened. From 22� C to 100� C the absorbance values dropped .26 (A). Literature Cited "Betacyanin" A Dictionary of Biology. Oxford University Press. Online 2000. http://www.xrefer.com/entry/459827 Ibrahim, A. ; Quick, J. Heritability of Heat Tolerance in Winter and Spring Wheat. Crop Science Sept. 2001 v41 i5 p1401 Jin, A.J. ; Edidin, M. ; Nossal, R. ; Gershfeld, N.L. A Singular State of Membrane Lipids at Cell Growth Temperatures. Biochemistry Sept. 1999 13275-13278 Marcum, Kenneth Cell Membrane Thermostability and Whole-plant Heat Tolerance of Kentucky Bluegrass. Crop Science Sept.-Oct. 1998 v38 n5 p1214 Olmsted, J and Williams, G. Chemistry. 3rd Edition . New York: Wiley & Sons, 2002. Solomon, Eldrea et al. Selected Chapters from Biology. California: Brooks.Cole, 2002. Visco, F. Cell and Molecular Biology Lecture Manual. Orange Coast College, 2002. ...read more.

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