Emma+Nutrition+Pre+Lab+HW

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? -they function for quick and short energy-term energy storage in all organisms 2. What is the difference between a simple carbohydrate and a complex carbohydrate? DESCRIBE EXAMPLES - if the number of carbon atoms in a carbohydrate is low, from three to seven it is called a simple sugar. Pentose means 5 carbon sugar, hexose means 6 carbon sugar. Glucose is an example of a hexose that our bodies use as an immediate source of energy. A disaccharide is made by joining two monosaccharides together, an example of this would be Maltose which is an example of two glucose molecules. Complex Carbohydrates are also known as polysacchraies. For example, starch, glycogen and cellulose are polysaccharides that contain many glucose units. Some of the macromolecules in starch are chains as long as 4,000 glucose units. 3. What is starch? What is the source of starch? - Starch is a macromolecule that contains many glucose units it is also a readily stored form of glucose in plants 4. What is "fiber" and of what benefit is it in the diet? - fiber is basically a molecule that can not be digested by the digestive system and therefore serves the purpose to stimulate the large intestine to produce fecal matter as well as preventing cholesterol from being absorbed into the small intestine. 5. Why does low-carb dieting work sometimes? But what are the risks? -Low-carb dieting can work because too many carbs can increase weight gain, but high fiber carbs on the other hand prevent constipation and high cholesterol which could have resulted in diabetes or heart disease. 6. What is the function of fats and oils? DESCRIBE EXAMPLES -Fats are used for long-term energy storage, insulating heat loss and forming a protective cushion around major organs. 7. What are fats and oils composed of? - fats and oils are formed when one glycerol molecule reacts with three fatty acid molecules. 8. What is the difference between a saturated and unsaturated fat? DESCRIBE EXAMPLES - saturated fats have no double bonds between the carbon atoms. Unsaturated fats have double bonds in the carbon chain whereever the number of hydrogens is less than two per carbon. Oils present in cooking oils, and bottled margarines are unsaturated fats and are liquid at room temperature. Butter is a saturated fat and is solid at room temperature. 9. What are the uses of phospholipids in the body? DESCRIBE EXAMPLES -phospholipids are the primary components of cellular membranes and they spontaneously form a bilayer in which the hydrophilic heads face outward towards water and the hydrophobic tails face inward to form the interior. 10. What are the uses of steroids in the body? DESCRIBE EXAMPLES - steriods are used to build muscle strength but can very harmful to the body because creating too much cholesterol can cause fatty mterial to accumulate inside the lining of the blood vessels, reducing the blood flow. 11. Why do we need fat in our diet? DESCRIBE EXAMPLES - Because fat provides needed energy. It is difficult to eat the large amounts of food in a very low fat diet to get all the energy you need. 12. What are the major functions of proteins in organisms? DESCRIBE EXAMPLES -Support- proteins make up our structure, including hair,nails, and collagen which lends support to ligaments, tendons and skin -Enzymes- speed up chemical reactions in cells they are specific for one particular type of reaction and can function at body temperature -Transport-some proteins such as channel and carrier proteins allow substances to enter and exit cells through the plasma membrane. Other proteins transport molecules in the blood of animals; hemoglobin is a complex protein in red blood cells that transports oxygen. -Defense- proteins called antibodies combine with foreign substances called antigens. The antibodies then prevent the antigens from destroying cells and disrupting homeostasis -hormones- also known as regulatory proteins serve as intercellular messengers that influence the metabolism of cells. For example, the hormone insuline regulates the content of glucose in the blood and the presence of growth hormone determines that height of an individual. -motion- the contractile proteins called actin and myosin are responsible for for allowing parts of cells to move which causes muscles to contract which results in the movement of animals from place to place 13. What is the subunit of a protein? How do they get their name? -the subunit of a protein is called amino acid. This name was derived because amino acids consist of an amino group and an acid group 14. How does the shape of a protein relate to its function? DESCRIBE EXAMPLES - Proteins have such an unusual shape so that when they are denatured and experience a change of shape it is no longer able to perform its usual function. Examples of denaturation are seen when acid is added to milk and curdling results as well as when heat is added to egg whites and the protein called albumin coagulates.