1. What is a scientific theory? Please cite a definition you like. As Watson stated in "The Value of Theories"‚ a scientific theory is a systematic explanation that unifies various observed phenomena and facts. Based on observations we make‚ science operates under theories which are constantly revised and checked by experiment. A scientific theory also possesses many vital qualities for true understanding. 2. What is the difference between a scientific theory and common sense ideas about the same
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Review Chapter 4 BB Notes Cells Under the Microscope Cells are microscopic in size. Although a light microscope allows you to see cells‚ it cannot make out the detail that an electron microscope can. The overall size of a cell is regulated by the surface-area-to-volume ratio. 4.2 The Plasma Membrane The plasma membrane of both prokaryotes and eukaryotes is a phospholipid bilayer. The phospholipid bilayer regulates the passage of molecules and ions into and out of the cell. The fluid-mosaic model
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of stem cell research. Stem cells offer people hope by promising to greatly extend the number and range of patients who could benefit from transplants‚ and to provide novel therapies to treat debilitating diseases such as diabetes‚ Parkinson’s‚ Huntington’s‚ heart disease and stroke‚ as well as accidental damage such as spinal cord injury. So why would anyone object to research in this area? The problem is simply that a particular type of stem cell‚ which potentially could provide many cell types for
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Stem Cell Controversy Stem cells were first isolated and cultured in November of 1998 and have been surrounded with much debate and controversy since day one. “Although the ethical debates have been mostly static and have closely mimicked the ethical debates over abortion‚ the political determinations concerning federal funding of stem cell research have gone through numerous evolutions in the years since the first hESCs were isolated and cultured” (Saltzberg 505). Research is currently being
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Synchronizing Cells at Specific Stages of the Cell Cycle The protocols presented here describe procedures used to synchronize cells in various stages of the cell cycle (Fig. 8.3.1). Synchronization is particularly useful for investigating a particular cell cycle–regulated event or preparing cells for extraction of transient factors whose expression is dependent on cell cycle stage. Exponentially growing cultures are generally asynchronous; i.e.‚ each cell progresses through the cell cycle independently
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After reading the “‘Bubble baby’ stem cell” paper I have come to the conclusion that stem cell research is an excellent thing. The reason why I think that is if we never do research and create a cure for “Bubble baby disease” then we will continue to lose babies. But‚ if we risk a few lives of babies for research in the long run it will save millions if not billions of lives. In this essay I will give three reasons on why I think stem cell research is a great thing. “Bubble baby disease.” In my
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Exercise 13 MITOSIS: REPLICATION OF EUKARYOTIC CELLS ANSWERS TO QUESTIONS 1. a. Mitosis and cytokinesis are often referred to collectively as "cellular division." Why are they more accurately called cellular replication? The result of mitosis is production of two cells (replicates) identical to the parent cell. The genetic material is replicated rather than divided. b. Does the cell cycle have a beginning and an end? The organization of our study of cellular events indicates a beginning and
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the solution and a potato tuber of a given size. The purpose of this experiment is to demonstrate how living cells rely on osmosis‚ the diffusion of water. Osmosis is the movement of water molecules (H20) from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall‚ which lets smaller molecules‚ such as water‚ through but does not allow bigger molecules‚ such as glucose
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CELL TRANSPORT MECHANISMS AND PERMEABILITY Zack Johnson Human Anatomy & Physiology Lab 2101 Instructor: Alan Byboth‚ M.S. 10/4/12 Abstract- The cell is invaluable building block of all biological life on this planet‚ and one of its most important and unique characteristics is its ability to be selectively permeable with its plasma membrane. This outer membrane’s sophisticated mechanisms of transport through its bilayer are vital in maintaining homeostasis in the cell and the entire
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century‚ little was known about cell membranes. Until the early 1950s‚ the biological cell membrane was rarely mentioned in scientific literature. It was recognised that something was probably there‚ but hardly anything about it was known. Considering the lack of technical equipment available a century ago‚ scientists such as Charles Overton and Edwin Gorter were not only exploring new territory in looking at the properties of cell membranes‚ but laying the way for future cell biologists. Scientists had
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