Digestion and Absorption Essays - Digestive System, Hepatology

Digestion and Absorption Essays - Digestive System, Hepatology Introduction The key issue in the digestion and absorption of fats is one of solubility. Lipids are hydrophobic, and thus are poorly soluble in the aqueous environment of the digestive tract. The digestive enzyme, lipase, is water soluble and can only work at the surface of fat globules. Digestion is greatly aided by emulsification, the breaking up of fat globules into much smaller emulsion droplets. Bile salts and phospholipids are amphipathic molecules that are present in the bile. Motility in the small intestine breaks fat globules apart into small droplets that are coated with bile salts and phospholipids, preventing the emulsion droplets from re-associating.The emulsion droplets are where digestion occurs. Emulsification greatly increases the surface area where water-soluble lipase can work to digest triacylglycerol. Lipase is a pancreatic enzyme that catalyzes the breakdown of fats to fatty acids and glycerol or other alcohols. Lipase is primarily produced in the pancreas, but is also in th e mouth and stomach. Most people produce enough pancreatic lipase. But people with cystic fibrosis, Crohn's disease, and celiac disease may not have enough lipase to get the nutrition they need from food. Lipase is an enzyme which catalyzes the degradation of triglycerides. More generally known as Lipoprotein Lipase(LpL). This is a catabolic reaction. Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine, with an equation of ; Fats (lipids) Fatty acid and glycerol. Lipase hydrolyses the fat in milk to fatty acids which react with sodium carbonate to lower the pH of the mixture. This pH change is observed by using phenolphthalein. Procedure (a) Firstly , label three test-tubes 1-3. (b) Next , using a pipette or syringe, place 5 ml milk in each tube. (c) Rinse the pipette and use it to place 7 ml dilute sodium carbonate solution in each tube. This solution is to make the mixture alkaline. (d) Rinse the pipette or syringe and use it to place 1 ml 3% bile salts solution in tubes 2 and 3 only. (e) Use a dropping pipette to add phenolphthalein solution to each tube until the contents are bright pink. About six drops will be sufficient and equal quantities should be added to each tube. Phenolphthalein is a pH indicator. In alkaline solutions (above pH10) it is pink; in 'acid' solutions (below pH 8.3) it is colourless. (f) In a spare test-tube, place about 15 mm of 5% lipase solution and, using a test-tube holder, heat the liquid over a small Bunsen flame until it boils for a few seconds. Cool the tube under the tap and, using the graduated pipette or syringe, transfer 1 ml of the boiled liquid to tube 2. (g) With the pipette or syringe, place 1 ml unboiled lipase solution in tubes 1 and 3. (h) Note the time. Shake the tubes to mix the contents, return them to the rack and copy the table below into your notebook, observing the tubes from time to time. (i) Note the time required for the contents of each tube to go white and then complete the table of results. Results Tube 1 (Lipase only): took 6 mins 42 secs to turn from pink to clear/white Tube 2 (Boiled Lipase, Bile salts): remained pink after 15 minutes Tube 3 (Lipase and bile salts): 2 mins and 11 secs Discussion The result obtained is different because all three test tubes are tested with different condition and materials. From the result function of bile salts is known and what will a boiled lipase will result. Test tube 1 shows the change in phenolphthalein after 4 minutes, where you used no bile. This is the time it takes for lipase to break down ordinary fats to fatty acids and glycerol (the production of the acids causes the colour change). Test tube 2 doesnt show any changes for 15 minutes due to boiled lipase which is used to show the denaturing effect of heat on enzymes (which are proteins). Heating the lipase destroyed its structure, which in turn prevents its action. This means that no fats are converted, even in the presence of bile but emulsification still occurred in this tube. Test tube 3 took 2 minutes plus to change colour because the

The Colorful History of Lipstick

The Colorful History of Lipstick Lipstick by definition is a cosmetic used to color lips, usually crayon-shaped and packaged in a tubular container. No individual inventor can be credited as the first to invent lipstick as it is an ancient invention, however, we can trace the history of the use of lipstick and credit individual inventors for creating certain formulas and methods of packaging. The First Lip Coloring The actual term lipstick wasnt first used until 1880, however, people were coloring their lips long before that date. Upper-class Mesopotamians applied crushed semi-precious jewels to their lips. Egyptians made a red dye for their lips from a combination of fucus-algin, iodine, and bromine mannite. Cleopatra was said to have used a mixture of crushed carmine beetles and ants to color her lips red. Many historians give credit to the ancient Arab cosmetologist, Abu al-Qasim al-Zahrawi for inventing the first solid lipsticks, which he described in his writings as perfumed sticks rolled and pressed in special molds. Innovations in Lipstick Packaging Historians note that the first cosmetic lipstick manufactured commercially (rather than homemade products) occurred around 1884. Parisian perfumers had begun to sell lip cosmetics to their customers. By the late 1890s, the Sears Roebuck catalog started to advertise and sell both lip and cheek rouge. Early lip cosmetics were not packaged in their familiar tubes that we see used today. Lip cosmetics were then wrapped in silk paper, placed in paper tubes, used tinted papers, or sold in small pots. Two inventors can be credited with inventing what we know as the tube of lipstick and made lipstick a portable item for women to carry. In 1915, Maurice Levy of the Scovil Manufacturing Company invented the metal tube container for lipstick, which had a small lever at the side of the tube that lowered and raised the lipstick. Levy called his invention the Levy Tube.In 1923, James Bruce Mason Jr. of Nashville, Tennessee patented the first swivel-up tube. Since then the Patent Office has issued countless patents for lipstick dispensers. Innovations in Lipstick Formulas Believe it or not, the formulas for making lipstick used to consist of such things as pigment powders, crushed insects, butter, beeswax, and olive oil. These early formulas would only last for a few hours before going rancid and often had ill effects on ones health. In 1927, French Chemist, Paul Baudercroux invented a formula he called Rouge Baiser, considered to be the first kiss-proof lipstick. Ironically, Rouge Baiser was so good at remaining on ones lips that it was banned from the marketplace after being considered too hard to remove. Years later in 1950, chemist Helen Bishop invented a new version of long-lasting lipstick called No-Smear Lipstick that was very successful commercially. Another element of lipstick formulas effects is the lipsticks finish. Max Factor invented lip gloss in the 1930s. Like much of his other cosmetics, Max Factor first invented lip gloss to be used on movie actors, however, it was soon worn by regular consumers