The CELL THEORY‚ or cell doctrine‚ states that all organisms are composed of similar units of organization‚ called cells. The concept was formally articulated in 1839 by Schleiden & Schwann and has remained as the foundation of modern biology. The idea predates other great paradigms of biology including Darwin’s theory of evolution (1859)‚ Mendel’s laws of inheritance (1865)‚ and the establishment of comparative biochemistry (1940). Ultrastructural research and modern molecular biology have
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DESCRIBE THE STRUCTURAL COMPARTMENTATION OF MAMMALIAN CELLS AND THE DIFFERING FUNCTIONS OF THESE COMPARTMENTS? Mammalian cells are eukaryotic this means that all of their cells have common components‚ membrane bound organelles which prokaryotic cells do not this is shown in figure 1. Organelles are purpose made to carry out a specific function that is necessary within a cell. Due to the specificity of both conditions and concentrations with in these organelles these are compartmentalized. Encasing
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The cell wall is the tough‚ flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection. Just as the wall of the factory is for the factory. The wall also is the structure and strength. The cell membrane that separates the interior of all cells from the outside The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances
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Cell Organelles Nucleus Its function is to control the cell’s activities and retain the chromosomes. The nucleus is bound by a double membrane‚ the nuclear envelope. The nuclear envelope has pores in it to allow the transport of mRNA. The cytoplasm like material is called nucleoplasm which contains chromatin (coils of DNA and histone proteins)‚ it is chromatin that condenses to form chromosomes during cell division. Within the nucleus is a small spherical body called the nucleolus which
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1. INTRODUCTION A solar cell is a device that converts the energy of sunlight directly into electricity by the photovoltaic effect. Sometimes the term solar cell is reserved for devices intended specifically to capture energy from sunlight‚ while the term photovoltaic cell is used when the light source is unspecified.”Photovoltaics” the field of technology and research related to the application of solar cells in producing electricity for practical use.
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Plant Cell Plant cells have many different parts that are need to work together and function as a whole. These parts are the cell membrane which can be compared to a "Condom" due to the fact that is a very thin protective layer that lets certain substances to pass through. Cell wall is a thicker rougher membrane‚ which gives the plant most of its structure and support‚ the cell wall also bond with other cell walls to form the structure of the plant. Centrosome may be also referred to as the
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body‚ there are billions of cells that are essential to living – these are called nerve cells. Nerve cells‚ also known as neurons‚ “are the basic information processing structures” (Stufflebeam). There are about 100 billion of these neurons in our nervous system and are the most essential cell in it. Located in brain as well as the spinal‚ there are different types of nerve cells; including: sensory neurons‚ motor neurons‚ and interneuron (Boeree). The neuron is a cell that is structured similarly
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treatment of many diseases. Stem cell research has provided hope and has brought optimism among the scientists and doctors in curing the patients who suffered or died due to the once called "untreatable" diseases decades ago. Stem cells are the ones which can develop into any type of a body cell including the cells of blood‚ liver‚ brain‚ muscles‚ and many more. They are found in adult bone marrow‚ embryos‚ fetuses‚ and blood from the umbilical cord (Bailey 100). Stem cell research is the latest advancement
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background knowledge relating to the current cell theory‚ the differences between prokaryotes and eukaryotes‚ and the structures and functions found within cells. Once this knowledge is known‚ a person is then able to give their opinion in the debate. In the 1800s‚ the cell theory was developed. This theory states that cells are found in all living things making them the basic units of life and that all cells come from other cells. In order to be classified as a cell‚ the object in question must be able
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fundamentals of science. Title An investigation of an onion cell using a light microscope. Aim: The aim of this investigation is to identify the cells within an onion skin using a light microscope. An onion cell is a plant cell which through the light microscope‚ it should outline the cell wall‚ cell membrane and the nucleus. Introduction: Plant cells have a cell wall and cell membrane which animal cells do not have. The cell wall provides support and is relatively rigid‚ which consists of
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