3.1 BIOLOGICAL MEMBRANES 3.1.1 Properties of Cell Membranes • Separates living cell from its nonliving surroundings. • 8 nm thick. • Selectively permeable - allows some substances to cross more easily than others. 4.1.2 Fluid Mosaic Model • Singer and Nicolson (1972) - plasma membrane is a mosaic of proteins dispersed within lipid bilayer‚ with only bilayer‚ the hydrophilic regions exposed to water. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein
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Extended experimental investigation: effects on membranes of environmental stress Background It is not possible to observe membranes directly‚ so this investigation is an indirect study of the effects of different substances and treatments on living beetroot cells. Beetroot cells have been chosen for this activity because each beetroot cell has a large central vacuole bounded by a membrane (Figure 1). Contained in the vacuole is the red pigment anthocyanin‚ which gives the beetroot its
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Cell Membrane Transport The purposes for these experiments is to be able to understand osmosis and its relationship to tonicity of solutions‚ and the transportation of molecules across cell membranes. It’s also used to understand‚ and how temperature affects diffusion. You also learn how to test for presences of starches and sugars in solutions. In the first exercise I will be testing for diffusion through an artificial membranes. This one has forty five steps to it. I will not go into
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Biology – HSC Online Extract from Biology Stage 6 Syllabus (Amended October 2002) © Board of Studies‚ NSW 9.2 Maintaining a balance: 1. Temperature range Background: All organisms are adapted to a particular environment with its characteristic temperature range. The temperature range allows the organism’s enzymes to control its metabolism by operating at their optimum efficiency within this range. Some organisms are adapted to live at high temperatures (80 - 100oC) and these are called thermophiles
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development and differentiation (e.g.‚ morphogenesis). Differences in surface-to-volume ratios affect the capacity of a biological system to obtain resources and eliminate wastes. Membranes allow cells to create and maintain internal environments that differ from external environments. The structure of cell membranes results in selective permeability
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Biology 1010 is a course that introduces students to the basic biological phenomena in all living organisms. It focuses on the different molecular levels of organization‚ heredity in evolution‚ genetics and reproduction. Through this course‚ I was able to master three essential concepts such as Mendel’s Law of Segregation‚ enzymes‚ and photosynthesis. Gregor Mendel was an Augustinian monk that argued that parental traits are passed on to their offspring discrete “heritable factors”. Heritable factors
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passive transport as energy does not need to be generated. Diffusion is complete when the concentration of molecules is equal on either side of the membrane. Diffusion rate can be influenced by many factors such as: Concentration gradient across the the membrane. Permeability of the membrane to the diffusing substance. Temperature. Surface area of the membrane. Question 2 2.1 Acetylcholine is an organic chemical that functions in the brain and body as a neurotransmitter it is an ester of acetic acid
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Which of the following are also found in the cell membrane: lipids‚ proteins‚ or carbohydrates? What is the role of steroids in a cell membrane? Cell membranes contain all three of the above groups‚ lipids are found abundantly in cell membranes‚ steroids are a type of lipids which helps with membrane fluidity by restricting the motion of the fatty acid tails. PROTEINS 1. Scroll down to proteins. List the six functions
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There are many kind of cell membrane disease‚ There are : Cystic Fibrosis Cystic Fibrosis is a disease that cause by gene mutation of CFTR Protein. CFTR it’s stand for Cystic fibrosis transmembrane conductance regulator. This disease causes too much production of thick mucus‚ then the mucus will blocked the ion transport in epithelial cells that line the passageways of the lungs‚ pancreas‚ and other organs. If the passageways of the lungs is blocked by the thick mucus‚ it will make the sufferer
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Bacteria Bacteria are microscopic organisms whose single cells have neither a membrane-enclosed nucleus nor other membrane-enclosed organelles like mitochondria and chloroplasts. Another group of microbes‚ the archaea‚ meet these criteria but are very different from the bacteria in other ways. In fact‚ there is considerable evidence that you are more closely related to the archaea than they are to the bacteria! Bacteria are living things that are neither plants nor animals‚ but belong to a group
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