Nutrition+questions+EAT

Read 2.4 Carbohydrates 2.5 Lipids 2.6 Proteins Answer the following questions... 1. What is the usual function of various carbohydrates in humans? 2. What is the difference between a simple carbohydrate and a complex carbohydrate? DESCRIBE EXAMPLES 3. What is starch? What is the source of starch? 4. What is "fiber" and of what benefit is it in the diet? 5. Why does low-carb dieting work sometimes? But what are the risks? 6. What is the function of fats and oils? DESCRIBE EXAMPLES 7. What are fats and oils composed of? 8. What is the difference between a saturated and unsaturated fat? DESCRIBE EXAMPLES 9. What are the uses of phospholipids in the body? DESCRIBE EXAMPLES 10. What are the uses of steroids in the body? DESCRIBE EXAMPLES 11. Why do we need fat in our diet? DESCRIBE EXAMPLES 12. What are the major functions of proteins in organisms? DESCRIBE EXAMPLES 13. What is the subunit of a protein? How do they get their name? 14. How does the shape of a protein relate to its function? DESCRIBE EXAMPLES
 * They are for the storage of quick and short-term energy
 * simple carbohydrates
 * When the number of carbon atoms in the carbohydrate is low (three to seven)- it is a simple sugar (monosaccharide). They can come in "pentose" (five-carbon sugar) or in "hexose" (6-carbon sugar). Glucose is the hexose in out bodies and is used as an immediate source of energy. If the cells get the needed amount of oxygen they cells will be able to break down glucose and give the body the energy needed.
 * other Hexose include
 * fructose (found in fruits) and galactose (which is a constituent of milk)
 * a disaccharide is made up of two mono saccharides bonded together by a dehydration reaction. (Maltose is a disaccharide that has two glucose molecules). When hydrolytic digestive juices break down maltose it creates two glucose molecules- when the glucose and fructose are joined the disaccharide sucrose is made. Sucrose (usually derived from sugarcane and sugar beets) is better known as table sugar.
 * complex carbohydrates
 * Macromolecules like glycogen, and cellulose are called polysaccharides and contain many glucose units. Starch (potatoes, bread and cake) and Glycogen are stored forms of glucose (found in plants and animals). After we eat complex carbohydrates the glucose enters the bloodstream and then the liver stores the glucose as glycogen. the release of hormone insulin from the pancreas triggers the glucose to be stored as glycogen.
 * polysaccharide cellulose is found in walls of plant cells. the glucose units are bonded by a special linkage that is unique to cellulose. this is very important because we are unable to digest foor that has this type of bond, so cellulose usually passes through our body and is used like fiber.
 * simple carbohydrates are mono saccharides and complex carbohydrates are polysaccharides.
 * It is a stored form of glucose that is found in plants and animals. Potatoes, bread and cake are examples of starchy-foods.
 * cellulose is a form of fiber. it is joined by a special bond that makes our body unable to digest. this is a benefit to our diet because it allows us to get rid of our waste. It stimulates movement in the large intestine- preventing constipation.
 * beans, peas, nuts, fruits, and vegetables are high in fiber.
 * too much carbohydrates can cause weight gain. if you lower you intake of carbs you can loses some weight- but it is important to have carbohydrates that have fiber so that you can prevent constipation and help people have a lower chance of heart disease and cancer.
 * Fat and oil are used as long-term energy storage. fat also insulates against heat loss and makes a protective layer around most major organs.
 * emulsifiers use fats to mix with water- they contain molecules that have a non polar end and a polar end- th molecules move around and position themselves into an oil drop so that the polar ends project outward- the drop then disperses into water and the emulsification has happened. (when dirty clothes are washed with soaps or detergents)
 * fats and oils are made when one glycerol molecule reacts with three fatty acid molecules
 * saturated fat they dont have a double bond with their carbon atoms the chain of carbons is "saturated" with all of the hydrogens it can hold.
 * saturated fat is associated with cardiovascular disease because they generate lipid material (plaque) to pile up inside the blood vessels.
 * butter- and is a solid at room temperature
 * unsaturated fat has double bonds in the carbon chain where the number of hydrogens is less than the two "per" carbon
 * unsaturated fatty oils have been found, in some cases, to prevent cardiovascular disease.
 * cooking oils and bottled margarines which are liquid at room temperature are generally unsaturated fats.
 * they are made like fats except that instead of the third fatty acid there is a phosphate group or a grouping that has both phosphate and nitrogen. they are not neutral because the phosphate and nitrogen groups are ionized (they form the polar end of the molecule while the other bonds create the "hydrophobic tails")
 * they are the primary parts of the cellular membranes- they make a bilayer where the heads are against the cell wall towards the water solution and tails are towards the middle of the cell forming the hydrophobic interior.
 * they are lipids that have a completely different structure than fats. they are made of four fused carbon rings. steroids are usually used to build muscle- but they are illegal because they are harmful to the body. they are capable of creating too much cholesterol to accumulate in the lining of the blood vessels and will reduce blood flow.
 * we need a little fat in our diet. it is important to know what type of fat you are eating. you should eat about 65 g of fat in a 2,000 calorie died. unsaturated fats have been found to prevent people from cardiovascular disease.
 * proteins are the primary source of structure and function of the cells.
 * some proteins (keratin) makes up hair, nails, and collagen which support the ligaments, tendons and skin. enzymes bring reactants together and speed up chemical reactions in cells. channel and carrier proteins in the plasma membrane allow substances to enter and leave the cells- other proteins transport molecules in the blood. hemoglobin in red blood cells is a complex protein that that transports oxygen. antibodies protect the body by preventing antigens from destroying cells and upsetting homeostasis. hormones regulate- they serve as an inter cellular messenger that influence the metabolism of cells- it regulates the content of glucose in the blood and cells. then contractile proteins (actin and myosin) allow parts on cells to move and cause muscles to contract.
 * one of the bonds (NH2) is called an amino group and the other group (COOH) is called an acid group- therefore they make the subunit "amino acid"
 * when proteins are exposed to high temperatures and pH they go through an irreversible change in their shape called "denaturation". when you add an acid to milk it causes curdling and that heating causes egg whites (which contain the protein albumin) to coagulate. denaturation occurs because the normal bond between the R groups has been disturbed- once a protein has lost its original shape it cannot perform its usual function.