To find out which concentrations of sucrose solution cause water to be gained or lost by osmosis in potatoes.
INVESTIGATING OSMOSIS IN POTATO'S Aim: To find out which concentrations of sucrose solution cause water to be gained or lost by osmosis in potatoes. Background: The spontaneous passage or diffusion of water or other solvents through a semi permeable membrane (one that blocks the passage of dissolved substances--i.e. solutes). The process, important in biology, was first thoroughly studied in 1877 by a German plant physiologist, Wilhelm Pfeiffer. Earlier workers had made less accurate studies of leaky membranes (e.g., animal bladders) and the passage through them in opposite directions of water and escaping substances. The general term osmose (now osmosis) was introduced in 1854 by a British chemist, Thomas Graham. If a solution is separated from the pure solvent by a membrane that is permeable to the solvent but not the solute, the solution will tend to become more dilute by absorbing solvent through the membrane. Increasing the pressure on the solution by a specific amount, called the osmotic pressure, can stop this process. The Dutch-born chemist Jacobus Henricus van't Hoff showed in 1886 that, if the solute is so dilute that its partial vapor pressure above the solution obeys Henry's law (i.e., is proportional to its concentration in the solution), then osmotic pressure varies with concentration and temperature approximately as it would if the solute were a gas
Factors that Affect the Rate of Yeast of Activity
Factors that Affect the Rate of Yeast of Activity Aim: We are going to investigate the factors that affect the rate of yeast activity. Plan: we are going to have three sets of experiments, with five experiments in each. The first five experiments will be investigating the effects if temperature is altered. In this experiment the yeast and substrate (glucose) will stay constant in all five beakers. The five beakers will be filled with 50ml of water, with the same amount of yeast. We will then add the substrate. The amount of glucose will be 2 molar, which is equal to 19.8g. I worked this out by the following calculations; Mr 198.17 Molecular mass of glucose 198.17 - X 20ml = 3.9g = 1 molar 1000 3.9 x 2 = 7.9g › 20ml, 2 molar My five different temperatures will be 0ºc, room temperature, 30ºc, 40ºc and 50ºc. The first five experiments will be used to see the effect that different temperatures have on the yeast. We are going to measure the amount of carbon dioxide given off. Ideally we want to measure the quantity of alcohol produced but this would require a hydrometer, which we do not have. The second set of experiments will see how the results change when molarity of the substrate (glucose) is changed. In these five experiments the temperature will be constant at 40ºc, which is yeast's optimum level. I know this from the research I have previously done. The
Digestion coursework
Biology Test on Nutrients and Digestion Nutrients Carbohydrates * Contain: carbon, oxygen, hydrogen * Found in pasta, potatoes, bread, rice and sugars * Needed for energy-movement, digestion and warmth * Excess stored as glycogen in liver and muscles * Made from: Monosaccharide- single sugar unit e.g. glucose, fructose, galactose - Soluble - Small (not digested, pass directly in blood stream) Disaccharides- two sugar units e.g. sucrose, lactose, maltose - Soluble - Too large (needs to be digested) Sucrose glucose + fructose Lactose glucose + galactose Maltose glucose + glucose Polysaccharides - many sugar units: - Starch- plant storage substance, digested by amylase enzymes in salvia and pancreatic juice - Cellulose- found in plan cell walls, cannot be digested by mammals as do not have cellulase, helps stimulate muscles in gut (peristalsis) - Glycogen- animal storage Too much carb causes obesity Too much sugar can rot teeth Fats * Contain: carbon, hydrogen, oxygen * Found in: butter, oil, margarine, peanuts, fatty meat * Needed for a) energy b) Insulation c) Storage of vit A and D * Excess stored under skin and around body organs * Made from fatty acids and glycerol Too much cholesterol blocks arteries Too much fat causes obesity Proteins * Contain: carbon, hydrogen, oxygen, nitrogen * Found: meat, eggs, fish, cheese, pulses *
Fermentation process
Fermentation Yeast is a microorganism containing an enzyme which will convert a sugar (glucose) solution into carbon dioxide and alcohol (ethanol). The word equation for fermentation is Glucose + yeast carbon dioxide + ethanol. Carbon dioxide gas bubbles out of the solution into the air leaving a mixture of ethanol and water. Ethanol can be separated from the mixture by fractional distillation. Fermentation must be carried out in the absence of air to make alcohol. If air is present, ethanoic acid is made instead of alcohol. Yeast is used in a batch process to make alcohol in beer and wine. An enzyme in yeast acts on the natural sugar in malt (to make beer) and grapes (to make wine). When the alcohol concentration reaches about 10%, the alcohol damages the yeast and fermentation stops. In a batch process the reaction vessel must be emptied and cleaned and then refilled with the new starting materials. A batch process takes more time and is more expensive than a continuous process. Different alcoholic drinks contain different amounts of alcohol. Some people drink alcohol for enjoyment, some drink to excess and some people become addicted to alcohol. The harmful effects (physical and social) of drinking excess alcohol are widespread and reach all parts of society. Ethanol can be made on a large scale for use as a fuel or solvent by the hydration of
Kidney Failure
Kidney Failure can be caused by: . Kidney Infections - can cause inflammation of kidneys which can damage the cells. This interferes with filtering in renal capsules or with reabsorption in other parts of the nephron. 2. High B.P can damage glomeruli. Blood in glomeruli is already under high pressure but capillaries can be damaged if blood pressure gets too high. Hence, larger molecules like proteins can get through capillary walls and into urine. Kidney Failure can cause a lot of problems: Waste products build up - e.g. urea which can cause weight loss and vomiting Fluid accumulates in the tissues because the kidneys can't remove excess water from the blood causing parts of the body to swell, also if salt build-up. Ions become imbalanced as blood may become too acidic and calcium/phosphate imbalance can lead to brittle bones. Long -term kidney failure causes anaemia- a lack of haemoglobin in the blood. Renal Dialysis:- Machine used to filter blood. Blood flows on one side of a partially permeable membrane and dialsysis fluid flows on the other side. Waste products and excess water and ions diffuse across the membrane into the dialysis fluid, removing them from the blood. Blood cells and larger molecules like proteins prevented from leaving
