NST 10 - Exam 1 Review Sheet

NST 10 - Exam 1 Review Sheet - INTRODUCTION AND MY...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: INTRODUCTION AND MY PYRAMID 1. What are some general concepts of the Dietary Guidelines for Americans? Are these guidelines food ­based or nutrient ­based? • NST 10 – Introduction to Human Nutrition Department of Nutritional Sciences & Toxicology University of California, Berkeley Spring 2011 Exam 1 Review 4 General Concepts: (1) to get more nutrients and less calories (nutrient ­dense food), (2) improve the balance between food and exercise (physical activity), (3) limit dietary components (nutrients) that contribute to chronic disease (trans fat, saturated fat, sodium (salt), cholesterol, alcohol, added sugars, etc), (4) keep food safe. 2. What are the food groups MyPyramid is organized into? What does MyPyramid symbolize? • 5 groups: grains, dairy (milk), fruits, vegetables, meat & beans; plus oils • • Symbolizes: (1) *variety (you cant get all your nutrition from one food group), *proportionality, *moderation (within each group – choose more nutrient dense food), *activity, gradual improvement, personalization The wider base represents the nutrient ­dense whole foods that should be chosen most often. The narrower tip represents the foods that should be eaten less often–those with more discretionary kcalories from added sugars and solid fats. 3. What does 3 oz of meat look like? 1 oz of grain? What size does a small fist or a baseball represent? • • • • • 3 ounces of meat or tofu is the size of a deck of cards 1 oz of grain is about 1 slice of bread, 1 cup of breakfast cereal, or half cup of cooked rice, cereal, or pasta. An ounce ­equivalent of grains is a slice of bread, a half bagel, or a half cup of pasta or rice. One cup of rice is the size of a baseball. A medium apple is the size of a baseball 4. What are discretionary calories? Give a few examples of foods that provide these calories. • • • • • The energy left over after an individual has consumed all the food needed to meet their nutrient needs. The kcalories remaining after you have met your nutrient needs by consuming nutrient ­dense foods from each of the food groups In a typical diet some of these  ­discretionary kcalories come from foods within the food groups such as cookies, cakes, and doughnuts that contain solid fats and added sugars Others come from dietary substances not in a food group such as butter and margarine, added table sugar, sweetened carbonated beverages, and alcohol. For a 2000 ­kcalorie diet the discretionary kcalories remaining after the specified number of nutrient ­ dense choices have been made from each food group is about 265 kcalories. 5. What are the key things you should look for on the food label when choosing a healthy food? • Serving size; total kcalories (on food labels the term “Calorie” is used to represent kcalories); kcalories from fat; the amounts of total fat, saturated fat, trans fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, and protein per serving; and how the food fits into the overall diet. 6. What are the differences between structure/function, health and nutrient claims? What are the requirements for nutrient claims? • a. Structure and Function Claims Ex. “Calcium Builds Strong Bones” 1 Describes how a nutrient affects a structure or function of the body No disease can be mentioned Not FDA approved, manufacturers are responsible for accuracy b. Health Claims • Ex. “Calcium Prevents Osteoporosis” • Describes the relationship between food, nutrient, or food constituent, and disease risk – NOT a product and disease risk (ex. Cannot say Kellogs Crunchies prevents heart disease; can say diets low in saturated fat and cholesterol that include 4g of soluble fiver from whole oats per day may reduce the risk of heart disease. Kellogs Crunchies has 2 grams of soluble fiber per serving.) • Allowed when there is significant scientific agreement for the association, FDA approved. • Must use may or might qualifier • To use a health claim is must a “good source” (≥10% DV) of at least one of these: fiber, protein, vitamin A, C, calcium, or iron. • AND have no more than 13 g of fat, 4 g saturated fat, 60 mg cholesterol, or 480 mg sodium in one serving. c. Nutrient Claims • Describes the amount of nutrient in a food. The claim is valid only “per serving.” If they eat more than 1 serving, they are eating more than the claim states. • The claims below mean nothing to consumers when they don’t know the definition. It is important to know the difference between claims on the label and facts on the nutrition panel. The nutrient facts are always the best source for nutrition information. • Nutrition Facts Panels can be a very useful tool in identifying healthy food choices to be incorporated into a well balanced diet that suits an individual’s tastes and dietary needs. The Nutrition Facts Panel compares food nutrient content to general standards, whereas the food pyramid can help consumers to develop a plan that individualized. Claim Definition Saturated fat ­free Less than 0.5 g per serving and the level of trans fat does not exceed 0.5 g per serving Low ­fat 3 g or less per serving Low calories 40 kcal or less per serving Calorie free Fewer than 5 kcal per serving Reduced/less At least 25% less per serving than the reference food. Good source >10% DV of nutrient (excellent source of vitamin C ­ must contain at least 20% of the Daily Value for vitamin C. • • • Digestion 1. List the primary organs involved in digestion. • Mouth (chews food and mixes it with saliva), pharynx (swallows chewed food mixed with saliva), esophagus (moves food to the stomach), stomach (churns and mixes food; secretes acid and a protein ­ digesting enzyme), small intestine (completes digestion; absorbs nutrients into blood or lymph), large intestine (absorbs water and some vitamins and minerals; home to intestinal bacteria; passes waste material), anus (opens to allow waste to leave the body). Salivary glands (produce saliva, which contains a starch ­digesting enzyme), liver (makes bile, which aids in digestion and absorption of fat) , gallbladder (stores bile and releases it into the small intestine when needed), and pancreas (releases bicarbonate to neutralize intestinal contents; produces enzymes that digest carbohydrate, protein, and fat). 2. What are the accessory organs for digestion? • 2 3. What are the factors that contribute to “Heartburn”? • • 4. What are the factors that influence the rate of gastric emptying? • • • • Heart Burn: acid from stomach refluxes back into the esophagus at the esophageal sphincter Contributing Factors: eating large portions of foods, lying down after eating, certain foods can be triggers, smoking/alcohol, overweight, tight ­fitting clothes, gestational hormonal changes, enlarged uterus during pregnancy Rate influences by: volume – stomach becomes distended (large vs. small meal) Composition: Fat, protein, carbohydrate, solid, liquid A large meal will take longer to leave the stomach than a small meal, and a solid meal will leave the stomach more slowly than a liquid meal. A high ­fat meal will stay in the stomach the longest because fat entering the small intestine causes the release of hormones that slow GI motility, thus slowing stomach emptying. A meal that is primarily protein will leave more quickly, and a meal of mostly carbohydrate will leave the fastest. Loss of pyloric sphincter function – regulates the rate at which material leaves the stomach Loss of a short term storage reservoir Loss of some chemical and enzymatic digestions Fast release of chime into small intestine. Vitamin and mineral deficiencies – small intestine has less surface area of nutrient absorption Absorb water and electrolytes (Na, Cl, K) Formation and storage of feces Microbial fermentation: depends greatly on species o Humans: short chain fatty acids important for health of intestine 200 ­2000 ml/day of gas – bacteria produces a lot of gas o 99% is N2, O2, CO2, H2, methane Consumption of indigestible carbohydrates (beans) causes increased fermentation and gas. Rectum and Anus Gastrin: A hormone secreted by the stomach mucosa that stimulates the secretion of gastric juice. o Made in mucosa of stomach, stimulates secretion of HCL, increase gastric motility and emptying o The stomach starts grinding by the gastrin; the stomach empties after becoming acidified o The brain organizes the section of gastrin. Secretin: A hormone released by the duodenum that signals the release of pancreatic juice rich in bicarbonate ions and stimulates the liver to secrete bile into the gallbladder. o Tells the pancreas to start secreting bicarbonate; tells the liver to secrete bile. CCK: A hormone released by the duodenum that stimulates the release of pancreatic juice rich in digestive enzymes and causes the gallbladder to contract and release bile into the duodenum. o Tells the gallbladder to release bile into the GI track; tells the pancreas to release enzymes. • Diffusion: The movement of substances from an area of higher concentration to an area of lower concentration. No energy is required. Vitamin E and fatty acids are absorbed by simple diffusion. Osmosis: The passive movement of water across a semi ­permeable membrane in a direction that will equalize the concentration of dissolved substances on both sides (simple diffusion of water!); move from an area with a lower concentration of dissolved substances to an area with a higher concentration of dissolved substances. Facilitated Diffusion: The movement of substances across a cell membrane from an area of higher concentration to an area of lower concentration with the aid of a carrier molecule. No energy is required. 5. What are the consequences of not having a stomach? • • • • • • • • • • • • 6. What are the functions of the large intestine? 7. What are the functions of gastrin, secretin and CCK (hormones that regulate digestion)? • • 8. What are the ways that nutrients get absorbed and how are they different? • • 3 • Active Transport: The transport of substances across a cell membrane with the aid of a carrier molecule and the expenditure of energy. This may occur against a concentration gradient. (ENERGY IS REQUIRED) o This use of energy allows substances to be transported against their concentration gradient from an area of lower concentration to an area of higher concentration Stomach: absorbs alcohol, water – doesn’t absorb food Small intestine (most absorption occurs here): absorbs carbs, proteins, lipids, most vitamins, water, and alcohol. Large Intestine: water, Na & K (electrolytes) (short chain fatty acids from bacteria) Ulcers occur when the mucosa is eroded away, exposing the underlying tissues to the gastric juices Ulcers can result from GERD or the chronic use of drugs such as aspirin and ibuprofen that erode the mucosa of the GI tract, but, as previously discussed, ulcers are more often caused by a bacterial infection in the stomach Infection of stomach by H. pylori, acid ­resistant bacteria that penetrate the mucous layer and damage the epithelial lining (ulcers are most often from this type of bacteria infection). 9. Where nutrients are specifically absorbed within the GI tract? • • • • • 10. What are some common causes of stomach ulcers? • 11. Fill in the blanks. Food that is broken down and moist is called a bolus. Once the bolus (same word from previous blank) enters the stomach it is converted to chyme. By the time water absorption has occurred in the large intestines the chyme is converted to feces. 12. What are the differences between Probiotics and Prebiotics? What is one problem associated with using probiotics, and what can you do to fix the problem? • Research supports the hypothesis that bacteria in fermented dairy products, such as Bifidobacterium and Lactobacillus, provide health benefits. Consuming products such as yogurt that naturally contain these bacteria, and supplements containing live bacteria, is referred to as probiotic therapy. Probiotics improve the digestion of the sugar lactose in lactose ­intolerant people, prevent diarrhea associated with antibiotic use, reduce the duration of diarrhea due to intestinal infections and other causes, and have beneficial effects on immune function in the intestine. There is also evidence that probiotics may relieve constipation, reduce allergy symptoms, modify the risk of colon cancer, and affect body weight. One problem with probiotics is that when they are no longer consumed, the added bacteria are rapidly washed out of the colon. However, you can promote the growth of a healthy population of bacteria by consuming substances called prebiotics. Prebiotics are indigestible carbohydrates that pass into the colon where they serve as a food supply for bacteria, stimulating the growth or activity of certain types of bacteria. Prebiotics are found naturally in onions, bananas, garlic, and artichokes and are currently sold as dietary supplements. 13. Give the final products and any important intermediates in the breakdown of the following: carbohydrates, sucrose, maltose, lactose, fiber, fats and proteins. Intermediate Products Final Products Carbohydrates Shorter chains of glucose Sucrose Glucose and fructose Maltose Glucose Lactose Glucose and galactose Fiber Fats Fatty Acids and Glycerol Proteins Polypeptides, amino acids Fill out the table based on key enzymes and hormones important for digestion. Take note of each macromolecule and its primary location of digestion. Digestive Organ Carbohydrates Lipids Protein Mouth – Saliva moistens the food so Salivary amylase can that it can easily be tasted and break the long sugar swallowed; it begins the enzymatic chains of starch in 4 digestion of starch; it cleanses the mouth and protects teeth from decay; and it lubricates the upper GI tract. Saliva begins the chemical digestion of carbohydrate because it contains the enzyme salivary amylase. Stomach foods like bread and cereal into shorter chains of sugars. (Salivary Amylase: An enzyme secreted by the salivary glands that breaks down starch.) Salivary amylase breaks starch into shorter chains of glucose. Small Intestines Hormones: Secretin/CCK . Large Intestines Gall bladder Liver Pancreas Pancreatic amylase: Breaks starch into shorter glucose chains and maltose. Lipase: Breaks monoglycerides into fatty acids and glycerol; break triglycerides into fatty acids Lipase: Breaks triglycerides into monoglycerides, fatty acids, and glycerol. Pepsin: A protein ­digesting enzyme produced by the gastric glands. It is secreted in the gastric juice in an inactive form (pepsinogen) and activated by acid in the stomach. Breaks proteins into polypeptides and amino acids. Gastrin: A hormone secreted by the stomach mucosa that stimulates the secretion of gastric juice. Gastrin then triggers the release of gastric juice and increases stomach motility. Rennin: cause milk protein casein to curdle. CARBOHYDRATES, FIBER AND SUGAR 1. What are the 2 main classes of Carbohydrates? What distinguishes them? 5 • • 2. What are the 3 most common monosaccharides? • • Simple Carbs (sugars): Monosaccharide (a single sugar unit, such as glucose, galactose, and fructose) and Disaccharide (A sugar formed by linking two monosaccharides, such as sucrose, lactose, and maltose); Fruits, vegetables, and milk are sources of simple carbohydrates. Complex Carbs (starches & fiber): polysaccharides (Carbohydrates containing many sugar units linked together; LONG chains; starch, glycogen, fiber) and oligosaccharides (short chain carbohydrates containing 3 to 10 sugar units.) The polysaccharides include glycogen (not in foods – you make glycogen; glycogen is the storage form of glucose (carbohydrate) in animals and starch and fiber in plants Glucose: A monosaccharide that is the primary form of carbohydrate used to provide energy in the body. It is the sugar referred to as blood sugar. Fructose: A monosaccharide that is the primary form of carbohydrate found in fruit. (Tastes sweeter than glucose, found in fruits and vegetables and half of honey); High-fructose corn syrup is sweeter and less expensive than table sugar; produced by modifying starch extracted from corn to produce a syrup that is approximately half glucose and half fructose Galactose: A monosaccharide that combines with glucose to form lactose or milk sugar; rarely present as a monosaccharide in the food supply (just like glucose) • 3. Disaccharides: Fill in the Blanks and Circle an answer choice.  ­ Glucose + fructose = sucrose : not easily/easily digested  ­ Glucose+ glucose = maltose : not easily/easily digested  ­ Galactose+ glucose = lactose: not easily/easily digested 4. What happens to glucose in the liver cells? • After absorption, monosaccharides travel to the liver. Glucose may also be broken down to provide energy, or passed into the bloodstream for delivery to other body tissues that can use it to provide energy. It may also be stored in the liver as glycogen and, to a lesser extent, used to synthesize fat. Stimulates GI motility (increase of bulk and draws water into intestine) Slows Nutrient Absorption (e.g. glucose and soluble fiber binds bile) Promote Healthy Microflora (bacteria can digest soluble fiber: excrete short chain fatty acids for health of colonic cells; many beneficial species inhibit undesirable species) Increases Intestinal Gas (e.g beans) A high fiber diet increases volume of food needed to meet energy needs Insoluble Fiber: Fiber that, for the most part, does not dissolve in water (binds to water, excreted) and cannot be broken down by bacteria in the large intestine. It includes cellulose (bran), plant cell walls, and lignin. Ex. wheat bran and rye bran (cellulose) & vegetables such as broccoli (lignin) Soluble Fiber: Fiber that dissolves in water or absorbs water to form viscous solutions and can be broken down by the intestinal microflora. It includes pectins, gums; can be digested by bacteria in the large intestine, producing gas and short ­chain fatty acids, small quantities of which can be absorbed. Ex. oats, fruit  ­ apples, beans, and seaweed Insulin: A rise in blood glucose triggers the pancreas to secrete insulin; controls transport of glucose from blood stream INTO muscles and fat cells. In muscle, insulin stimulates the uptake of glucose for energy production and the synthesis of muscle glycogen for energy storage. Insulin also stimulates protein synthesis and, in fat ­storing cells, it increases glucose uptake from the blood and stimulates lipid synthesis. Glucagon: triggers the pancreas to secrete glucagon when glucose level in the blood begins to decrease. Elicits release of glucose OUT of liver and glycogen stores; Glucagon signals liver cells to break down glycogen into glucose, which is released into the bloodstream. 5. What are the physiological effects of dietary fiber? What is insoluble fiber? Soluble fiber? • • • • • • • 6. What are the hormones that regulate blood glucose? How do they do it? • • 7. T/F. When blood glucose is high, glucagon is secreted into the circulatory system. 6 8. Circle all that apply to Type 1 Diabetes a. Destruction of β  ­cells of pancreas b. Can no longer make insulin c. Late ­onset d. Early ­onset e. Represents 90 ­95% of those with diabetes f. Cells can’t take up glucose because of insulin resistance g. Symptoms include weight loss, fatigue, and frequent urination (Type II also) h. Risk factors include being physically inactive and having low HDL cholesterol 9. What is Type 1 diabetes? What is Type 2 diabetes? What are their differences? What are the risk factors for Type 2 diabetes? • Type 1: destruction of β ­ cells of pancreas; can no longer make insulin; consequences: cells cant take up glucose: to much circulating glucose outside cells; too little glucose inside cells. Treatment: insulin injections plus strict diet Type 2: 90 ­95% of diabetic have Type II; the body make insulin: but cells’ insulin receptors don’t respond to insulin; INSULIN RESISTANCE. What happens? Cells don’t take up glucose; too much circulating glucose Difference: Type 2 takes a long time to develop (late onset), Type 1 early onset; in Type 1 – insulin is no longer produced, Type II – insulin is produced but no response to the insulin. Risk factors: #1 risk: family history of diabetes (genetics), excess abdominal fat, sedentary lifestyle. • • • 10. What are the components of a whole grain? What’s the difference between whole grain and refined grain? • • • • Bran: The protective outer layers of whole grains. It is a concentrated source of dietary fiber. Germ: The embryo or sprouting portion of a kernel of grain. It contains vegetable oil, protein, fiber, and vitamins. Endosperm: The largest portion of a kernel of grain. It is primarily starch and serves as a food supply for the sprouting seed. Whole grain includes germ, bran, and endosperm – it is nutrition Refined gain – just endosperm; Fiber and some vitamins, minerals, and phytochemicals naturally found in the whole grain are therefore lost. 11. How many grams of sugar are in a teaspoon? A tablespoon? • There are 4 grams of sugar per teaspoon. • There are 12 grams of sugar per tablespoon. 12. What is lactose intolerance? • The inability to digest lactose because of a reduction in the levels of the enzyme lactase. It causes symptoms including intestinal gas, diarrhea, abdominal discomfort, and bloating after dairy products are consumed. Not enough lactase to digest lactose. Not allergy to milk. The AMDR for carbohydrate intake for a healthy diet has been set at 45% to 65% of energy The sources of carbohydrate are more important than the absolute amount. In order to restore some of the lost nutrients, refined grains sold in the United States are fortified with some, but not all, of the nutrients lost in processing. Enriched grains contain added thiamin, riboflavin, niacin, and iron and are fortified with folate. However, they do not contain added vitamin E, magnesium, vitamin B6, or a number of other nutrients that are also removed by milling. 13. What is the Acceptable Macronutrient Distribution Range for carbohydrates? 14. What is an enriched grain? What are such grains enriched with? • • • 15. The Reference Daily Intake for calcium is 1000 mg. If a food provides 150 mg of calcium, what is the %DV for calcium in this food? 7 150/1000 = .15 = 15% LIPIDS 1. List 5 uses of lipids in the body. 1. 2. 3. 4. 5. • • • • • Fuel: main form stored energy: almost limitless; primary fuel for muscle and heart; emergency fuel for illness and low kcal intake Cell Membranes: fat cells are metabolically very active – it sends a lot of signals to the rest of your body. Different cell membranes have slightly different components, but the bottom line is that these are “fat sandwiches.” Thermal insulation/brown fat: preterm babes typically do not have a lot of fat and are very susceptible to chilling – they have to be kept very warm; We all have, babies especially, brown fat – it generates heat (more active under cold conditions) Pad internal organs: like kidneys Converted to many other components: we use fat to make a lot of other kinds of chemicals. 2. What are the three ways to categorize fatty acids? Saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid. The physical properties of a fatty acid depend on the length of the carbon chain and the type and location of the bonds between the carbon atoms. There are a lot of different fatty acids – they differ in two main parameters: how long they are and how many double bonds are in them. Saturated fats = no double bonds – hydrogens on each carbon Unsaturated fats = carbon ­carbon double bond – meaning they are missing some hydrogens. They can have 1 double bond, two double bonds, 3 double bonds, or even more. EFA are required in diet – our body does not naturally make them. Omega 6 fatty acids: vegetable oils – olive oil, walnut oil. A fatty acid containing a carbon ­carbon double bond between the sixth and seventh carbons from the omega end; includes linoleic and arachidonic acid. Omega 3 fatty acids: cold water fish oil (cod liver oil), canola, flaxseed oil. A fatty acid containing a carbon ­carbon double bond between the third and fourth carbons from the omega end. 3. What are Essential Fatty Acids (EFA)? What are sources of EFA? • • • 4. Phospholipids = glycerol backbone +phosphate+ 2 fatty acids 5. Cholesterol is produced in the liver. 6. Why do we want to watch the amount of cholesterol consumed? • We make all we need  ­ cholesterol is necessary in the body, but because the liver manufactures it, it is not essential in the diet. Diets high in cholesterol increase the risk of heart disease but consuming plant sterols can help reduce cholesterol levels in the body by decreasing cholesterol absorption from the diet. 7. We need to consume cholesterol in our diet as cholesterol is used to make hormones and bile in our body. T/F 8. Bile is produced in the liver (regulate by Secretin) and secreted by the gallbladder (stimulated by CCK). 9. Enzymes begin to break down lipids before the emulsification process begins. T/F • AFTER emulsification 10. How does the chain length relate to absorption of fatty acids? • • These enzymes (lipases) work best on triglycerides containing short ­ and medium ­chain fatty acids such as those in milk, and so are particularly important in infants. How lipids are transported from the small intestine depends on their solubility in water. Short ­ and medium ­chain fatty acids, which are water ­soluble, can be transported from the small intestine in the blood and delivered to cells throughout the body. Lipids that are not soluble in water, such as long ­ chain fatty acids and choles ­terol, cannot enter the bloodstream directly so they must be incorporated into lipoproteins. 8 11. What is atherosclerosis? • • A type of cardiovascular disease that involves the buildup of fatty material in the artery walls. Narrowing and hardening of blood vessels that supply blood to the heart muscle, brain, and other parts of the body. • Inside gets smaller and thicker – not so much blood can go through a very thick blood vessel with a narrow bone. DIETARY FAT AND HEART DISEASE 1. What is the AHA recommendation for: ? a) Saturated Fats: Consume less than 10 percent of calories from saturated fat and less than 300 mg/day of cholesterol, and keep trans fat as low as possible. Keep total fat intake between 20 to 35 percent of calories, with most fats coming from sources of polyunsaturated and monounsaturated fatty acids. Limit intake of fats and oils high in saturated and/or trans fatty acids, and choose products low in such fats and oils. b) Trans Fats: refer to above statement. 2. What are the dietary sources for monounsaturated fatty acid? Omega ­3 and Omega ­6 fatty acids? • • • Monounsaturated Fats: fish, nuts, and vegetable oils; olive, peanut, or canola oil; snacks on nuts and seeds; Add olives, avocados, nuts, and seeds to your salad. Omega 3: flaxseed oil, cold water fish oil, canola oil, leafy green vegetable, walnuts, FISH Omega 6: vegetable oils – olive and walnut oil, nuts (almonds) 3. We should consume the same amount of omega ­3 and omega ­6 fatty acids, as they are essential fatty acids. T/F • A high intake of omega ­6 polyunsaturated fatty acids may also cause a slight decrease in HDL cholesterol, which is undesirable in terms of heart disease risk. Increasing omega ­3 fatty acid intake lowers levels of LDL cholesterol but not HDL cholesterol. #1  ­ Genetic defects (black clearance of chylomicrons and triglycerides in the blood, reduce LDL uptake by the liver, limit synthesis of HDL, enhance blood clotting) diet/activity/smoking, diabetes, high blood pressure, obesity, high circulating cholesterol, age, and gender high LDL, low HDL 4. What are the risk factors for heart disease? • 5. Fill in the blanks: a. 1g Carbohydrate = 4 kcal b. 1g Protein = 4 kcal c. 1g Fat = 9 kcal Make sure you can define the following terms! • Macronutrient: Nutrients needed by the body in large amounts. These include water and the energy ­yielding nutrients; carbohydrates, lipids, and proteins. Their requirements are measured in kilograms (kg) or grams (g). Micronutrient: Nutrients needed by the body in small amounts. These include vitamins and minerals. The amounts required are expressed in milligrams (1 mg = 1/1000 g) or micrograms (1 μg = 1/1,000,000) Calorie: “calorie,” is technically 1/1000 of a kilocalorie, but when it is spelled with a capital “C,” it indicates kilocalories. Kilocalorie: The unit of heat that is used to express the amount of energy provided by foods. It is the amount of heat required to raise the temperature of 1 kilogram of water 1 degree Celsius (1 kcalorie = 4.18 kjoules); 9 RDA: Intakes that are sufficient to meet the nutrient needs of almost all healthy people in a specific life ­stage and gender group. Because the RDA is set higher than the needs of most people, it serves as a target for individual intake. An intake less than the RDA does not necessarily indicate that the needs of that particular person have not been met, however, the risk of a deficiency is low if intake meets the RDA and increases as intake falls below the RDA Chylomicrons: Lipoproteins that transport lipids from the mucosal cells of the small intestine and deliver triglycerides to other body cells; chylomicrons enter lymph then go into the blood stream near the heart. Very large – one reason why they do not go into the blood system. PROTEIN 1. Generally, what is the structure of an amino acid and what distinguishes one amino acid from the other? • All amino acids have similar structure, but each has a different side chain. Each amino acid consists of a carbon atom bound to four chemical groups: a hydrogen atom; an amino group, which contains nitrogen; an acid group; and a fourth group or side chain that varies in length and structure. Different side chains give specific properties to individual amino acids. 2. What does protein turnover mean? What does the body start with and what types of end products are involved? • Amino acids are used to make proteins, but proteins are constantly broken down and synthesized – protein turnover 3. Describe generally the order of protein synthesis in the cell. Where does it take place and what are the steps? • Protein synthesis involves transcription and translation 10 4. What are good dietary sources of protein? Which are the most ecologically sound? Which sources are most common in developed and developing countries? • • • • • High protein foods: meats – beef, pork, poultry, sea foods Intermediate protein foods: dairy, soy products, legumes (beans), nuts, cereals Low protein foods: fruits, vegetables Most people in the United States and other developed countries have access to meats, eggs, and dairy products, which provide animal protein, and to legumes, grains, and vegetables, which provide plant sources of protein. Because of the availability and variety of foods in developed countries, protein deficiency is uncommon. However, in developing nations, concerns about inadequate protein are very real. Diets deficient in protein are most often deficient in energy as well, but a pure protein deficiency can occur when food choices are extremely limited and the staple food of a population is very low in protein. 5. How much protein do people need in their diets? What are the DGA recommendations? 6. What functions does protein serve in the body? • Structural proteins – hair, skin, muscle • Enzymes  ­ speed up metabolic reactions – all reactions to produce ATP use different enzymes • Transport proteins – transport substances in and out of cells – hemoglobin carries oxygen to cells and carries away carbon dioxide; myoglobin does same thing in the muscle • The RDA for protein for adults is 0.8 gram of protein per kilogram of body weight per day 11 • • • Know the following terms: Protein turnover: The continuous synthesis and breakdown of body proteins. Amino acids: he building blocks of proteins. Each contains a central carbon atom bound to a hydrogen atom, an amino group, an acid group, and a side chain. Side chain: each amino acids consists of this  ­ side chain that varies in length and structure; Different side chains give specific properties to individual amino acids. Essential amino acid or indispensable amino acids: Amino acids that cannot be synthesized by the human body in sufficient amounts to meet needs and therefore must be included in the diet. Nonessential amino acid or dispensable amino acids Amino acids that can be synthesized by the human body in sufficient amounts to meet needs. Extra Notes: • Saliva also protects against tooth decay because it helps wash away food particles and it contains Lysozyme—an enzyme that inhibits the growth of bacteria that may cause tooth decay Antibody proteins – fights foreign substances that invade and cause injury Protein hormones – secreted into the blood and act on target cells in other parts of the body – insulin controls blood sugar Contractile proteins – actin and myosin slide past each other during muscle contraction 12 ...
View Full Document

Ask a homework question - tutors are online