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FON 241: Module 5 Study Guide Chapter 6: Proteins: Crucial Components of All Body Tissues 1. Briefly explain how protein differs from carbohydrates and lipids. Proteins are similar to carbohydrates and lipids because they all contain carbon, hydrogen and oxygen. The difference is, proteins contain nitrogen. 2. a. Explain the structure of an amino acid. Each amino acid contains a central carbon which has the following attached to it: amino group (h2n), hydrogen, acid group (hco2), and a R-group. b. What structural factor(s) make amino acids differ from one another? The R-Group in each amino acid is different, making the amino acid differ from others. c. How many amino acids exist? 20 different amino acids exist. 3. a. How can the body synthesize protein? The body synthesizes proteins by transferring an amine group from one amino acid to a separate side chain and acid group, now a new amino acid can be formed. b. Explain transamination. Transamination is the synthesis of nonessential amino acids of the body. 4. What are essential and nonessential amino acids? Explain and giving examples. Essential amino acids are received through your diet and there are 9 total. An example of this is Histidine. Nonessential amino acids can be made from your body and there are 11 total. An example of a nonessential amino acid is Alanine. 5. Describe a condition where an amino acid is conditionally essential. What does conditionally essential mean? Phenylketonuria is a condition where an amino acid is conditionally essential which means a non-essential amino acid becomes an essential amino acid under special circumstances. 6. Explain the processes and importance of gene expression (transcription and translation). Gene expression is important because it is how it is how proteins are made from genes. Without this process new proteins would not be made and we always need more proteins made because proteins are being broken down at the same time. Transcription and translation are the steps to gene expression: DNA is copied and the new copy of DNA is not called mRNA (messenger RNA). This is called transcription. From here, the mRNA is transported to the ribosomes and can make newly synthesized proteins. This process is called translation. 7. What is the amino acid pool and why is it important to protein turnover? The body arranges amino acids in a specific order to make whichever protein it needs. These amino acids are taken from a pool of larger amino acids (the amino acid pool) to form specific proteins. Protein turnover explains how the body is constantly building and breaking down new proteins. It is important with the amino acid pool because amino acids from our diet and from the breakdown of body cells form the amino acid pool. 8. a. How is the function of a protein determined? The function of a protein is entirely determined by its shape.

b. Explain the four structural levels within a protein. The four structural levels within a protein are the primary structure; amino acids help together by peptide bonds, secondary structure; the twisting of amino acids within a chain, tertiary structure; a 3D structure that contains more complex versions of the twisting amino acid chains, and finally, the quaternary structure; two or more polypeptides interact and fold on themselves. 9. a. Identify the reasons a protein may uncoil. A protein may uncoil when the bonds that are holding the protein’s 3D structure are disrupted. b. Name this condition and explain how structure and function are affected. This condition is called denaturation and the proteins function is lost. For example, when we eat protein hydrochloric acid in the stomach denatures protein from food. Denaturation then increases the surface are, and enzymes can attack the peptide bonds. 10. Your body attempts to synthesize a protein, but one of the amino acids needed to complete this process is missing. Explain what happens. When your body is trying to make a protein, and discovers one of the amino acids is missing, a complementary protein can be consumed to fill in the missing essential amino acid to make it a complete protein. This process is called mutual supplementation. 11. With regard to health, discuss incomplete and complete proteins. Give food examples of each. Complete proteins contain all nine essential amino acids, Examples of a complete protein are animal products such as meat, dairy, and fish. Incomplete proteins do not contain all nine essential amino acids and are insufficient to support protein growth. An example of an incomplete protein are plant products such as lettuce. 12. How could a vegetarian obtain a complete intake of the essential amino acids in their diet? What about someone following a vegan diet? A vegetarian can obtain a complete intake of essential amino acids in their diet by being careful and through the process of mutual supplementation. This is when one food does not contain all nine essential amino acids, another type of food that contains the missing amino acid can be consumed to fulfill the complete protein. Vegans can do the same, although they will need to consume more of these complementary proteins because they are consuming no animal products exclusively. 13. Where does enzymatic digestion of protein begin? Digestion of proteins begin in the stomach. 14. Upon absorption into the intestinal cell, what happens to an amino acid? Before the digestion process reaches the intestinal cell, the protein’s shape unravels in the stomach and peptide bonds are broken. The protein then travels into the small intestine, and proteases from the pancreas break down protein into dipeptides and tripeptides. Then, intestinal cells absorb amino acids and are transported via portal vein to the liver.

15. Identify and explain a negative outcome of supplementation of single amino acids. A negative outcome of supplementation of single amino acids could mean that you are not receiving all 9 of your essential amino acids in one sitting. Therefore, you must turn to mutual supplementation and receive the missing amino acids from another food source. 16. Several enzymes are responsible for the digestion of protein. Identify three enzymes, explaining function and origination. Three enzymes that are responsible for the digestion of proteins are proteases, pepsinogen, and pepsin. Proteases come from the pancreas and further break down the protein into dipeptides and tripeptides. Pepsinogen and pepsin are found in the stomach and hydrochloric acid converts the inactive enzyme, pepsinogen, into its active form, pepsin which is a protein-digesting enzyme. 17. Explain what determines a protein’s quality. How can a food’s protein quality be estimated? A proteins quality is determined by the quantity of essential amino acids in a protein. There are several methods to estimate a food’s protein quality. For example, you can calculate a chemical score which is the comparison of the amount of the limiting amino acid in a food to the amount of the same amino acid in a reference food. The chemical score of a protein gives an indication of the lowest amino acid ratio calculated for any amino acid in a particular food. Another method is digestibility. This uses the chemical score and a correction factor for digestibility to calculate a value for protein quality. 18. Thoroughly list and explain the functions of protein in the body. Proteins have several functions in the body. They can function as enzymes and hormones which are protein that speed up chemical reactions and chemical messengers. Proteins aid in balance of fluid and electrolytes as well as maintain appropriate fluid levels in vascular system in blood. Other functions of proteins include: cell growth, repair, maintenance, acid-base balance, can act as antibodies to protect against disease, and an energy source. 19. Thoroughly explain the concepts and situations surrounding: a. Positive nitrogen balance: when the intake of nitrogen exceeds the amount of nitrogen being lost in the urine. People experiencing this situation could be someone who is pregnant, or recovering from an illness (healing). b. Negative nitrogen balance: this is when the nitrogen being excreted into the urine exceeds the amount of nitrogen being consumed. This can be found in people experiencing anorexia nervosa when their tissues are being broken down. c. Nitrogen balance: comparing the amount of nitrogen consumed to the amount of nitrogen excreted in the urine. A neutral balance (healthy), these two factors would be equal to each other. 20. You are a sedentary 20-year-old male weighing 200 pounds. What is the recommended amount of protein (in grams) you should consume each day? Show calculations. 200 pounds / 2.2 = 90.91kilograms 90.91 * 0.8grams = 72.73 72.73 grams of protein should be consumed daily by this particular person according to their weight.

21. Based on the Recommended Dietary Allowance, calculate your protein needs. Take into account activity levels. Show calculations. Considering myself as a non-vegetarian endurance athlete weighing 135 pounds I would need to consume 73.64 grams of protein every day. 135lbs / 2.2 = 61.36 kilograms. 61.36 * 1.2grams = 73.64 grams of protein. 22. You have a friend who has been following a high protein diet for several years. What potential health consequences may develop? A prolonged high protein diet could lead to some health issues including, risk of heart disease, increase calcium loss, and those with kidney issues, the high protein diet can stimulate these issues. 23. Vegetarianism has many forms. Define the following: a. vegetarian: someone who does not consume any form of meat coming from an animal. Limits foods from animal origin. b. vegan: someone who does not consume any type of food that has once come from any type of animal including meat, dairy, poultry, etc. Avoids all animal flesh and animal products. c. flexitarian: primarily a vegetarian but occasionally consumes meat or fish. d. lactovegetarian: abstains from eating meat and eggs, but will eat dairy products. e. pescovegetarian: only consumes fish as the only animal product. f. lacto-ovo-vegetarian limits animal products to milk and eggs 24. Explain three health benefits associated with a vegetarian diet. Three health benefirs associated with a vegetarian diet include: less saturated fats and more fibers in their diet which results in less cardiovascular issues. Also, vegetarian diets lead to lower blood pressure as well as few digestive problems. Lastly, people who follow a vegetarian diet have a reduced risk of some cancers, kidney disease, kidney stones, and gallstones. 25. Vegetarians of all types may be at risk for nutrient deficiencies. Identify four nutrients, including functions and food sources that may lack in a vegan diet. Four nutrients that may lack in a vegetarian diet are, Vitamin D, Vitamin B12, Calcium, and Iron. Vitamin D is found in fish, eggs, and milk and functions as building strong bones and absorbing calcium. Vitamin B12 is only found in animal products, therefore vegetarians would need to substitute vitamin B12 with a supplements of fortified foods. Calcium is found in salmon and function as an important mineral that the body needs. Vegetarians can substitute calcium with broccoli, fortified juices, or fortified soymilk. 26. Around the world, food sources of high quality protein are not as accessible as in developed countries. Identify and explain two diseases that result from protein-energy malnutrition. Two diseases that result in protein-energy malnutrition are Marasmus and Kwashiorkor. In marasmus, protein, energy, and nutrient intakes are all severely low. Resulting in body fat reserves being depleted and there is sever muscle wasting and stunting of brain and physical growth. Marasmus most often occurs in infants and children 6-18 months or in adults who have cancer or are in their end stage of AIDS. If untreated, Marasmus can lead to death. Kwashiorkor results from low protein intake. The one symptom that sets Kwashiorkor different from Marasmus is edema. Since proteins are unavailable to transport fat, the fat accumulates in the liver. This combined with edema results in a

bloated belly. If treated, this disease can be reversed making it not as severe as Marasmus. 27. Does protein supplementation increase muscle mass? What does your book say? Explain. Protein supplementation does not increase muscle mass, utilizing our muscles is what increases muscle mass. Since we rarely use protein for energy during exercise, consuming the healthy amount of protein and adhering to the recommended protein intakes based on your weight, age, and physical activity, will provide more than enough strength for a physical performance.