Topic 2 – Cell membranes Reading Chapter 5 Objectives Functions of cell membranes The fluid mosaic model The lipid bilayer – phospholipids‚ glycolipids and sterols Properties of the lipid bilayer Membrane proteins – the ‘mosaic’ in the model Solute movements across membranes BIO 1140 – SLIDE 1 http://www.nikonsmallworld.com/gallery/year/2006/id/751 Functions of cell membranes – an overview Fluid mosaic model Singer & Nicolson 1972 Fluid lipid molecules in which
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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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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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The Cell Theory The Cell Theory‚ formed by Anton van Leeuwenhoek‚ Robert Hooke‚ Matthias Schleiden‚ Theodore Schwann‚ and Rudolf Virchow‚ refers to the idea that cells are the basic unit of structure in every living organism. The theory justifies three principles: all living organisms are composed of one or more cells; the cell is the most basic unit of structure‚ function‚ and organization in all organisms; and all cells come from pre-existing‚ living cells. The formation of the cell theory
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ROD CELLS Rod cells‚ or rods‚ are photoreceptor cells in the retina of the eye that can function in less intense light than the other type of visual photoreceptor‚ cone cells. Rods are concentrated at the outer edges of the retina and are used in peripheral vision. On average‚ there are approximately 125 million rod cells in the human retina.[1] More sensitive than cone cells‚ rod cells are almost entirely responsible for night vision. STRUCTURE AND FUNCTION Rods are a little longer and leaner
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phones could cause health problems such as headaches or brain tumors. In addition‚ the devices those using RF radiations are safe. Such as: Radio had used RF radiation since 1893 and television had used RF radiation since 1939‚ and cell phone also uses RF radiation. So‚ cell phone absolutely safe. Research into mobile phones and health risks Intensive international research has found no conclusive or convincing evidence that mobile phones are damaging to health in the short or long term. However
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