Investigation On Osmosis

Investigation On Osmosis By Alex Rignall Investigation On Osmosis Aim To investigate how much change there is in the mass of a potato chip in varied concentrations of a sucrose solution. Prediction Osmosis: Osmosis is the movement of any of the solutions molecules 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 cell membrane or a partially permeable membrane, which lets small molecules through and does not let large ones through. I predict that the lower the concentration of sucrose in the solution the more the potato chips will expand. I can say this because I know that there will be more water molecules and therefore osmosis will take place between a lower concentration of water molecules and a higher concentration of water molecules that are separated by a partially permeable membrane such as a the cell membrane of the potato. The sucrose will not cross the partially permeable membrane because the molecules are too big to fit in between the gaps in the membrane. The higher the concentration of sucrose in the solution the more the chips will decrease in mass. I can predict this because from my previous prediction I know that the potato chip will have a higher concentration of water molecules, and therefore the water molecules in the potato chips will move across the partially

  • Word count: 2459
  • Level: AS and A Level
  • Subject: Science
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The Renal System.

The Renal System: The renal system consists of the bladder, kidneys (the kidneys are approximately eleven-cm long, six cm wide and four cm thick), urethra and the ureters. The kidneys are placed under the bottom of the rib cage and close to the spine. There are two functions of the renal system; these are to get rid of waste materials and to control the level of water in the body. Waste materials are removed from the blood and pass out through the body during the process of excreting urine. The levels of water in the body are controlled to ensure that the concentrations of different liquids within the body are kept within safety limits. This process is called osmoregulation. The kidney's function within the body is to clean the blood and get rid of anything the body doesn't want or need or that is harmful to its self. There is a large amount of space in the kidneys. People can not only survive with one kidney but also lead very healthy, active lives if they choose to do so. If a person is unfortunate to suffer from complete kidney failure, the blood allows waste materials to build up within the body as a result the levels of toxicity in the body rises. The body will eventually become poisoned internally if the kidneys can't clean the blood. Urea is produced in the liver; it is white in colour and is a crystalline substance. As the body doesn't store protein instead it

  • Word count: 1003
  • Level: AS and A Level
  • Subject: Science
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Whats involved in Homeostasis.

Homeostasis Homeostasis is involved in keeping the body's internal environment constant (like the thermostat of a central heating system). Homeostasis keeps the body's temperature at a certain level (36.5oC) and it keeps the pH of the body at a certain level so that enzymes don't denature. Blood glucose is kept constant, CO2 levels and O2 levels are monitored to ensure that enough oxygen and not too much carbon dioxide are in the blood. The overall concentration and volume of blood is also monitored homeostatically. Cannon first used the term Homeostasis in the late 1920s. Homeostasis is very important to animals because it allows them to rely on the external environment. A constant internal environment allows a considerable degree of independence and allows animals to live in areas from the arctic to the tropics. Many of the mechanisms involved rely on negative feedback. A movement from the set level (e.g. a rise or fall in body temperature) is detected by receptors. These receptors then send information to the control centre in the brain which reacts by returning to the original value. For example, the temperature control mechanism. Humans maintain body temperature within 1oC of 36.5. If the temperature rises too high, the resulting increase in blood temperature is detected by receptors in the hypothalamus in the brain. The heat loss centre also in the hypothalamus sends

  • Word count: 1599
  • Level: AS and A Level
  • Subject: Science
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The structure and function of carbohydrates.

The structure and function of carbohydrates Carbohydrates are named for their characteristic content of carbon, hydrogen, and oxygen (CH2O). Carbohydrate molecules are categorized by the number of carbons present in the molecule. Short chains containing from three to seven carbons form the monosaccharides, which are the most basic sugars. Monosaccharides with five or more carbons can form a ring as well as a linear configuration. The rings form through a reaction between two functional groups in the same molecule. Each carbon atom in the chain, except one, carries an -OH group. The remaining carbon carries a -C=O (carbonyl) group. In monosaccharides hydrogen atoms occupy all other available binding sites of carbon. Glucose, the most common monosaccharide has six carbons per molecule, which is called a hexose. Carbohydrates also have 2:1 hydrogen to oxygen ratio. This aids in the condensation and hydrolysis reactions. A condensation reaction occurs when two monosaccharides join by the removal of water (H2O). During condensation synthesis one monosaccharide losses an OH and the other losses an H. As a result the two monosaccharides bond by forming maltose a disaccharide with a by-product of a free H2O molecule. When three or more monosaccharides or monomer are involved in a condensation synthesis a polymer or polysaccharide is formed with a by-product of water. Starch and

  • Word count: 1596
  • Level: AS and A Level
  • Subject: Science
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What is Homeostasis?

Homeostasis is involved in keeping the body's internal environment constant (like the thermostat of a central heating system). Homeostasis keeps the body's temperature at a certain level (36.5oC) and it keeps the pH of the body at a certain level so that enzymes don't denature. Blood glucose is kept constant, CO2 levels and O2 levels are monitored to ensure that enough oxygen and not too much carbon dioxide are in the blood. The overall concentration and volume of blood is also monitored homeostatically. The term Homeostasis was first used by Cannon in the late 1920s. Homeostasis is very important to animals because it allows them to rely on the external environment. A constant internal environment allows a considerable degree of independence and allows animals to live in areas from the arctic to the tropics. Many of the mechanisms involved rely on negative feedback. A movement from the set level (e.g. a rise or fall in body temperature) is detected by receptors. These receptors then send information to the control centre in the brain which reacts by returning to the original value. For example, the temperature control mechanism. Humans maintain body temperature within 1oC of 36.5. If the temperature rises too high, the resulting increase in blood temperature is detected by receptors in the hypothalamus in the brain. The heat loss centre also in the hypothalamus sends

  • Word count: 1604
  • Level: AS and A Level
  • Subject: Science
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