The cell is the fundamental structural unit of all living organisms. Some cells are complete organisms‚ such as the unicellular bacteria and protozoa; others‚ such as nerve‚ liver‚ and muscle cells‚ are specialized components of multi-cellular organisms. Cells range in size from the smallest bacteria-like mycoplasmas‚ which are 0.1 micrometer in diameter‚ to the egg yolks of ostriches‚ which are about 8 cm (about 3 in) in diameter. Although they may differ widely in appearance and function‚ all cells
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Bacterial Energetics and Membranes Abstract The Mg2+/Ca2+ ATP synthase present in all bacterial membranes‚ particularly E. coli‚ couples ATP synthesis to the proton (H+) gradient produced by the ETC‚ a process known as oxidative phosphorylation. The gradient acts to power the ATPase‚ so that it may phosphorylate ADP to produce ATP. The reverse reaction of this process‚ or hydrolysis of ATP into ADP and Pi‚ may be used to observe ATPase activity when the resulting Pi is quantitatively measured
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Fuel cells have become a favorable future power source because they can convert chemical energy directly into electricity in a highly efficient‚ environmentally friendly manner. Although fuel cells were invented one and a half centuries ago‚ only recently has it become feasible for them to compete with existing energy production systems. Among the various types of fuel cells‚ proton exchange membrane (PEM) fuel cells promise to become a viable power source for transportation as well as a distributed
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The Effect of Salt Concentration on Osmosis in Potato Cells We should first explain what Osmosis is. It’s a passage of water from a region of high water concentration through membrane to a region of low water. Semi membrane is a very thin layer of material‚ which allows some things to pass through them but prevent other things from passing through. The cells allow small molecules like Oxygen‚ water‚ Carbon Dioxide‚ Ammonia. But will not allow larger molecules like Sucrose‚ Starch‚ or protein‚ etc
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Resting membrane potentials Definition: Large nerve fibers when not transmitting nerve signals is about 90 millivolt. That is‚ the potential inside the fiber is 90 millivolts more negative than the potential in the extracellular fluid on the outside of the fiber. The Na+-k+ pump also causes large concentration gradients for sodium and potassium across the resting nerve membrane. These gradients are the following: Sodium ( outside): 142 mEq/L Sodium ( inside): 14 mEq/L Potassium ( outside):
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INTERNATIONAL SCHOOL SIMPRUG Chemistry Assessment Task Student name : Class : 10 A Due date : 30 August 2010 Teacher : Ms. Merliani “How do chemical elements effect the environment” (1.236 words) Atmospheric pollution Most of the people live within the major cities where the evidence of pollution in the atmosphere can almost be seen daily. Your Task You will need to write an essay (700-1200 words) or prepare a presentation using the following guidelines
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The effect of different temperature on the cell respiration. Introduction： Cell respiration is the controlled release of energy from organic compounds in cells to form ATP‚and then release waste products. The process of cell respiration can take place in the presence or absence of oxygen. In either case‚the first stage of cell respiration is glycolysis.The effect of temperature on cell respiration mainly depends on the effect of temperature on of enzyme activity.Generally speaking in a certain
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Topic: “The effect of cell phone use on need for affiliation.” Hypothesis: Teenagers who use cell phones‚ use them to feel that they are affiliated with their social groups at all times. These teenagers use their cell phones as a convenient way to fulfill their need for affiliation‚ therefore taking the place of acquainting in person. Experimental Design: An experiment to prove my hypothesis could be to evaluate a control group and experimental group based on how many times they hang out with their
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BAD EFFECTS OF CELL PHONE ON SOCIETY A report by the International Telecommunication Union (ITU) said there were about six billion cell phone subscriptions at the end of 2011-roughly one for 86 of every 100 people. Up to now‚ this number has continued to increase dramatically. This proves certainly that cell phone affects our society more strongly and more deeply in many aspects. No one can deny that cell phone is playing a very important and necessary role in our society because it not only
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Twitter. The technological advancement that affects our writing the most is the cell phone. Cell phones have become such a must have item that people bring them where ever they go. Although this item is popular‚ there are pros and cons of using cell phones; including the effect cell phones have on our writing skills. Does text messaging affect our writing skills enough to completely stop text messaging though? Since the cell phone was first invented it has advanced more than we can imagine. These days
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