...Cells are the smallest form of life possible. All organisms have to consume air. Water is the building block of all life. Air is consumed, this process is referred to as respiration. In smart people talk this means an exchange of gases. Once the air is used to fuel the machine it is discarded as Carbon Dioxide. “Biologists also define respiration as the aerobic harvesting of energy from food molecules by cells. This process is called cellular respiration to distinguish it from breathing.” In everyday life we breathe, as we work harder physically like running, lifting heavy weight or any type of strenuous physical activity we require more oxygen. The air we breathe is taken in and deposited into the lungs, the lungs then distribute this air to the bloodstream to fuel the muscle cells in support of the higher demand of oxygen. The muscle cells extract energy from the protein and other valuable nutrients to generate ENERGY. This process is referred to as ATP. “Tonicity is how a cell loses or gains water from its surrounding solution. From here cells maintain the mass balance through a process called diffusion, all this means is the ability to spread out evenly in an available area. Isotonic simply means the ability to replace air, water, energy at the rate it is losing it. Hypotonic is a solution with a solute concentration less than the cell. Hypertonic is the opposite a solution with a higher solute concentration. Osmosis, the diffusion of water across a membrane...
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...CELL BIOLOGY AND GENETICS ASSIGNMENT TOPIC: CELL MEMBRANE [pic] INTRODUCTION Cell membranes are crucial to the life of the cell. It encloses the cell defines its boundaries, and maintains the essential difference between the cytosol and the extra cellular environment. Inside the cell the membranes of the endoplasmic reticulum, Golgi apparatus, mitochondria, and other membrane bound organelles in a eukaryotic cell maintain the characteristic differences between the contents of each organelle and the cytosol. Ion gradients across membranes, established by the activities of specialized membrane proteins, can be used to synthesize ATP to drive the transmembrane movement of selected solutes, or in nerve and muscle cells, to produce and transmit electrical signals. In all cells the plasma membrane also contains proteins that act as sensors of external signals allowing the cell to change its behavior in response to environmental cues; these protein sensors, or receptors, transfer information rather than ions or molecules across the membrane. [pic] THE STRUCTURE OF THE CELL MEMBRANE All biological membranes have a common general structure: each is a very thin film of lipid and protein molecules, held together mainly by non covalent interactions. Cell membranes are dynamic, fluid structures, and most of their molecules are able to move about in the...
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...An Educational Study on Cell Membrane Radiologic Pathology GUBALLO, MARIBETH S. BS RADTECH III INSTRUCTOR: DR. EMMANUEL PAGALA The Cell Membrane Cells are made of many vital parts that work together and perform specific functions. One important part of the cell structure is the cell membrane also known as the plasma membrane or cytoplasmic membrane. Historically, the plasma membrane was also referred to as the plasmalemma. The cell membrane is a microscopic lipid-based sheath that encloses the cytoplasm of a cell and separates the interior of all cells from the outside environment. It acts as a gatekeeper to ions and organic molecules such as DNA, RNA and other proteins by its selectively permeable barrier which enables the cell to regulate its internal environment and keep out foreign molecules that might damage or destroy the cell's contents, including molecules essential for life. Cell membranes also functions in different cellular processes such as cell adhesion, cell signaling and serve as the attachment surface for several extracellular structures. FUNCTION All prokaryotic cells have a phospholipid bilayer called the plasma membrane. It defines the boundary between the inside and outside of the cell even though it is found on the inside of the prokaryotic cell wall. The cytoplasm and other prokaryotic cellular contents are found inside the plasma membrane. On the other hand, all eukaryotic cells have a plasma membrane as well, but they also have additional...
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...The aim of this experiment is to investigate the influence of various alcohols and temperature on the permeability of beetroot cell membrane. The different types of alcohol will include ethanol, methanol, propanol, butanol and the tissue from the beetroot will be exposed different salt concentrations (0%, 5% ,10% and 20%) . The stress affecting the membrane’s permeability will be assessed by the amount of leakage of pigment caused. ‘Homeostasis the ability of the body or a cell to seek and maintain a condition of equilibrium or stability within its internal environment when dealing with external changes’ (Biology, 2014). Organelle membranes and the plasma membrane are selectively permeable, allowing water to pass through freely, but regulating the movement of solutes. The function of a cell membrane is to transport and allow certain substances into the cell, while keeping other substances out. Surrounding the cytoplasm of a cell, the cell membrane (plasma membrane) is a thin semi-permeable membrane (Bailey, 2014) consisting mostly of lipids and proteins and composed up of a phospholipid bilayer. This contributes to the selectively permeable nature of the membrane. 70% of proteins contribute to the cell membrane, allowing communication outside and inside the cell. The phospholipids arrange themselves so that hydrophobic tails are shielded from the surrounding water exposing the hydrophilic heads to the water. While small molecules and non-charged ions cross freely, big charged...
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...AP October 2, 2014 In the early twentieth century, little was known about cell membranes. For years scientists looked through the microscope in search of answers. Since the discovery of many new information conducted through observations and research, they were able to understand that plasma membrane is an essential biological structure to all cells. It functions as an envelope by keeping all a cells organelles contained. It also serves as a gateway and barrier to certain foreign substance. Although plasma membrane may seem simple on the outside, it’s actually a complex structure of molecules working in coordination with each other to function properly. The cell membrane, also known as the plasma membrane, is a phospholipid bilayer, which consists of Polar, hydrophilic phospholipid heads and non-polar, hydrophobic fatty acid tails. The plasma membrane is constructed in a specific way where phospholipid tails point towards each other, away from polar substances and the polar heads are positioned in the other direction towards aqueous environments. Because of this special chemically influenced arrangement of molecules, an impermeable membrane selective to small, non-polar is formed substances. The cell’s plasma membrane also contains a diverse array of proteins amidst its phospholipid layer. Proteins are extremely important as they carry out many specialized functions for the plasma membrane. Proteins imbedded in between the phospholipid bilayer are called integral proteins...
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...As the manager of the "cell team", i decided that the most valuable player is the cell surface membrane. Also known as plasma membrane, the cell surface membrane consists of a double layer of phospholipids. The hydrophilic heads of phospholipids face outwards into the water while the hydrophobic tails face inwards pointing each others. The two layered structure is known as the phospholipid bilayer. Intrinsic proteins will be found at the phospholipid bilayer to allow the transport of certain substances. Besides, cholesterols are present in the bilayer to maintain the mechanical stability of the membrane. Two scientists, Singer and Nelson made a hypothesis for the structure of the plasma membrane, which they named their model "fluid mosaic model"....
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...How substances cross the cell membrane. A cell’s membrane has many functions including forming a boundary in order to organise the contents and keep them separate from the extracellular environment. Yet in order for the cell to ‘live’ and perform its particular function, it needs to be able to take in substances and nutrients and to get rid of waste products. But with such a vast array of substances in the extracellular environment, it is a difficult task to control the influx and out-pouring of substances. There are several ways that this is accomplished and these are set out below. Cell, or plasma, membranes are formed from two layers of phospholipids which have a polar, hydrophilic head and a nonpolar, hydrophobic tail. This is known as the fluid mosaic model. It is this feature of membranes which makes them semipermeable and dictates how substances may cross them. Figure 1 shows a simplified structure of the cell membrane. Small, nonpolar molecules such as (O2), carbon dioxide (CO2) and nitrogen (N2) are able to diffuse passively across the membrane and do so down their concentration gradients or electrochemical gradients in the case of ions. However larger or charged molecules and ions require assistance of some type as they are too large or have a charge on them which prevents them crossing the hydrophobic interior of the membrane. In many cases a substance crosses the membrane with the assistance of membrane proteins, this is known as facilitated diffusion. Again...
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...Outline the roles of membranes at the surface of cells and within cells (10 marks) Both the cell surface membrane and the membranes surrounding certain organelles have the same basic structure and similar functions. There are 5 major roles of membranes including separating cell contents from the outside environment; separating cell components from cytoplasm; cell recognition and signalling; holding the components of some metabolic pathways in place and regulating the transport of materials into or out of cells. The phospholipid bilayer is the basic structural component of all biological membranes. A bilayer is formed when phospholipid molecules are completely surrounded by water. The hydrophilic (water-loving) heads stick in the water, while the hydrophobic (water-hating) fatty acid tails point towards each other in a mirror image. The formation of the tails creates a barrier to many molecules, separates the cell contents from the outside world and gives stability. Mechanical stability is supported by cholesterol in the bilayer. This steroid molecule fits between fatty acid tails and helps make the barrier more complete, so substances like water molecules and ions cannot pass easily and directly through the membrane. The structure of the membrane is called the fluid mosaic model because the membrane is fluid (the phospholipid molecules are not actually bonded) and because of the mosaic arrangement of the protein molecules. Inside the fluid mosaic model are various protein...
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...diffusing across a membrane? requires passive transport requires no energy requires active transport requires both a and b Which correctly describes the plasma membrane? fluid and nonpermeable rigid and nonpermeable fluid and partially permeable fluid and completely permeable Which component of the phospholipid bilayer is considered hydrophobic? phospholipid head phospholipid tail phospholipid head and tail none of the above Which correctly describes the fluid-mosaic model of the cell membrane? phospholipid monolayer with embedded proteins phospholipid bilayer with embedded proteins phospholipid monolayer with embedded triglycerides cholesterol bilayer with embedded proteins This process uses a carrier protein...
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...Summer Project Report Study of MDA (malondialdehyde) as abiotic stress marker in CSV-17 variety of Sorghum bicolor. Submitted in partial fullfilement of the requirement for B.Tech. Biotechnology Semester VII AMITY INSTITUTE OF BIOTECHNOLOGY AMITY UNIVERSITY RAJASTHAN JAIPUR 2011 Supervised by: Dr Ajit Kumar Sr. Research Officer S.P. Institute of Biotechnology, Jaipur Submitted by: Ravi Pareek DECLARATION I hereby declare that the project report entitled “Study of MDA (malondialdehyde) as abiotic stress marker in CSV-17 variety of Sorghum bicolor” is a record of the work compiled by me under the supervision and guidance of Dr. Ajit Kumar, S.P. Institute of Biotechnology, Jaipur as a part of my 45 days summer training. Ravi Pareek (B.TECH-BIOTECHNOLOGY) (AUR0821094) ACKNOWLEDGEMENT First of all with due regard to my respective god with whose kindness and blessing we could be able to accomplish the task of training. Mr. Sourabh Pareek, for his kind permission to allow me to undergo my major project at S. P. Institute of Biotechnology, Jaipur. I am overwhelmed with rejoice to take this opportunity to evince my profound sense of reverence and gratitude to my esteemed supervisor respective Dr. Ajit Kumar, for giving his regular advice and excellent suggestion which have helped us for completing the study. His regular assistance and guidance really helped me to bring formidable task in successful manner. Sincere thanks to Dr. Sonali Jana and Dr. Neha Upreti for their cooperation...
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...Unit One: Biochemistry Organic chemistry: chemistry of carbon based molecules * Life on our planet is carbon based * All life is carbon based, so to understand how biological processes occur we need to consider organic chemistry Hydrocarbons: molecules that are entirely made from carbon and hydrogen * Carbon you can get a lot of shape (rings etc) * Mostly non-metals (hydrogen, carbon, oxygen etc) make up molecules in our cells * Hydrogen, carbon, nitrogen, oxygen make 96% of living organisms however 21 elements found as well * Most of 4% consists of calcium, potassium, phosphorus, sulfur, sodium, chlorine, magnesium Functional Groups * Most functional groups are ionic or strongly polar which makes them very attracted to other ionic or polar molecules * Non polar portions do not attract other molecules so do not help initiate chemical reactions * So, some polar functional groups are strongly attracted to water and so can often be dissolved in the cytosol of the cell, example ethane is hydrocarbon doesn’t have functional group so does not dissolve in water and is gas at room temperature however ethanol has functional group so highly soluble in water Carbon Chemistry * Because it has has 4 electrons in shell so can form 4 covalent bonds to form these shapes * Can form bonds with others but can also bind with each other * Carbon containing rings can join to make polymers Dehydration and Hydrolysis...
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...Membrane Adaptation of Hyperthermophilic organisms Student’s Name Institution Affiliation Hyperthermophiles have some adaptations that enable them to live in hot environment. One of the adaptations is that of the membrane (Stetter, 1999). Since these organisms are subjected to high temperatures, they need to have extremely stable biomolecules to allow them to survive in hot environments. If the stability of the membrane of these organisms’ cell would be low, the cell could fall apart, and allow numerous molecules to flow in and out of the membrane destroying the chemical gradients used by the cells to generate energy and at the same time, allowing all the proteins that have already been synthesized by the cell to diffuse away, hence...
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...Introduction Most aspects of a cell depend on the fact that atoms and molecules have kinetic energy and are constantly in motion. Kinetic energy causes molecules to bump into each other and move into different places. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration. Cells have selectively permeable membranes that only allow the movement of certain solutes. Diffusion is vital for many of life’s functions in a cell. It allows oxygen and carbon dioxide exchange in the lungs and between the bodies of intracellular fluid and cells. An example of this process is the diffusion of a smell in a room. Eventually dynamic equilibrium will be reached. This means that the concentration...
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...different mechanisms used by the body to transport substances across the cell membrane. One of these methods is called Simple diffusion. Simple diffusion involves molecules diffusing from an area of higher concentration to an area of lower concentration. Simple diffusion happens through random movement of particles through the cell membrane. Carbon dioxide and other gases such as oxygen and ethanol uses simple diffusion as a method of cell transportation. Several factors affect the rate of diffusion including high temperatures and the size of the molecule. A smaller molecule will diffuse much quicker than a larger one as it is able to move about without difficulty. Concentration gradient and the distance of diffusion also makes a...
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...Volume - Cells are limited in their size because they must maintain a high “Surface Area : Volume” ratio. - Nutrients (oxygen and glucose) must enter a cell while wastes (carbon dioxide and urea) must exit a cell through the cell membrane. - The amount of cell membrane = Surface Area of the cell. - Inside the cell, organelles use up nutrients and produce wastes. The larger the cell, the more nutrients needed and the more wastes produced. - The size of the cell (based on the number of organelles) = Volume of the cell. [pic] Cell S.A Volume S.A. : Volume LxWx6 LxWxH Ratio A 6 units2 1 unit3 6 : 1 B 24 units2 8 units3 3 : 1 C 96 units2 64 units3 1.5 : 1 D 384 units2 512 units3 0.75 : 1 [pic] - Small cells have a high “SA:Volume” ratio, they can supply the organelles with plenty of nutrients and rapidly remove wastes. - Large cells have a low “SA:Volume” ratio because volume rises faster than surface area. If a cell gets too big, wastes will build up and nutrients will run out; cell cannot survive. - Therefore, cells are limited in their size. The more active a cell the smaller it must be. Active cells need more nutrients and they produce more wastes. - How do cells occupy the large volumes associated with large organisms? The cells reproduce frequently through mitosis to maintain their small size (high “SA:Volume” ratios) while creating millions of cells to fill these...
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