NHM 101- EXAM 2 Study Guide
NHM 101- EXAM 2 Study Guide NHM 101
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This 9 page Study Guide was uploaded by Alexia Acebo on Saturday October 3, 2015. The Study Guide belongs to NHM 101 at University of Alabama - Tuscaloosa taught by Libo Tan in Summer 2015. Since its upload, it has received 120 views. For similar materials see Intro Human Nutrition in Environmental Science at University of Alabama - Tuscaloosa.
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Date Created: 10/03/15
Carbohydrates what are they 9 Macronutrient 9Contain C H and O atoms usually with a HO atom ratio of 2 l 9The name hydrates of carbon comes from an early observation that heating these compounds produced water and a black residue of carbon 1 Dietary carbohydrates and sources 0 Starch grain products 0 Fiber legumes vegetables and 39uits 0 Sugars natural sugars milk fruits added sugars i Major Functions 1 Provide energy through their oxidation in the body energyproducing 2 Serve as a storage form of energy ie glycogen 3 Supply carbon atoms for biosynthesis of other organic molecules 4 Act as structural components Classi cation of carbohydrates a Simple carbohydrates i Monosaccharides single sugars l Glucose fructose galactose ii Disaccharides pairs of monosaccharides l Maltose sucrose lactose b Complex carbohydrates i Oligosaccharides 310 monosaccharides ii Polysaccharides long chain of monosaccharides l Glycogen starch ber Glucose is the energy source for all cells Maltose glucose glucose Sucrose glucose fructose Lactose glucose galactose Starch storage form of glucoseenergy in plants Glycogen storage form of glucoseenergy in animals liver and muscle Fiber cannot be digested Why 9 Bonds between bers monosaccharides cannot be broken down by digestive enzymes Carbohydrate digestion Begins in the mouth Functions of o pancreatic amylase Digest most starch to maltose o maltase digest maltose into glucose 0 lactase digest lactose to glucose and galactose o sucrase digest sucrose to glucose and fructose Digestion products glucose fructose galactose 4 Causes of lactose intolerance Lactase declines with age only about 30 of adults have enough lactase a b Lactase de ciency Intestinal villi are damaged by disease medications prolonged diarrhea 5 Glucose in the body Glycogen formation excess glucose in the body is stored as glycogen in the liver and muscles glycogen breakdown When blood glucose falls liver break down glycogen and release glucose into the blood which becomes available to supply energy to tissues Muscle break down their glycogen to use by themselves Gluconeogenesis the making of new glucose from body protein when adequate dietary carbohydrates do not exist Blood glucose homeostasis regulation by insulin and glucagon o Insulin Blood glucose rises 9 insulin released 9 moves glucose from blood into cells 9blood glucose returns to normal 0 Glucagon Blood glucose falls between meals 9glucagon released signals liver to breakdown glycogen stores blood glucose returns to normal Diabetesv blood glucose remains above normal after a meal due to inadequate or ineffective insulin 0 Type 1 Diabetes I Pancreas does not produce any or enough insulin I Typically diagnosed in childhood 0 Type 2 Diabetes I Cells do not respond to insulin I Typically occurs due to obesity 6 Identify added sugars on the ingredient label Corn syrup solids a b c d e f g h i Dextrose oFructose oHigh fructose corn syrup oHoney oLactose Malt Syrup Nectars Raw sugar j Sucrose 7 Health effects and Recommended intake a Sugar in excess can be detrimental b Obesity and Chronic Disease i Americans who drink sugarsweetened beverages have a higher energy intake 1 Weigh more with high intake of added sugar ii Increased risk of diabetes in ammation hypertension heart disease c Nutrient De ciencies i Foods and beverages containing lots of added sugars deliver very few essential nutrients or fiber d Dental Caries Reduce intake of kcal from added sugars According to the DRls sugar should make up no more than 25 of your kcal AMDR for carbohydrates 4565 gt Example Michael eats 2500 kcalories a day and 300 grams of carbohydrates Is he consuming enough carbohydrates according to the Acceptable Macronutrient Distribution Range for carbohydrates gt Answer 300 g 4 kcalg 1200 kcal 12002500 048 48 Yes Recommended intake of fiber for men and women gt Men 35 g or more gt Women 25 g or more Proteins 1 Amino acids Protein is made of amino acids Basic structure of amino acids 0 Central carbon atom 0 Hydrogen atom 0 Acid group COOH 0 Amino Group NH2 0 Side group varies with different amino acids Essential amino acids the body cannot synthesize o Histidine Isoleucine leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine 2 Structure of proteins Amino acids are linked by peptide bonds Dipeptide o Two amino acids bonded together Tripeptide 0 Three amino acids bonded together Polypeptide 0 Multiple amino acids bonded together Most proteins contain a few dozen to hundreds of amino acids Four levels of protein structures Primary Structure Amino acid sequence 0 The 20 amino acids can be linked together in a variety of sequences Secondary Structure Polypeptide Shapes 0 Sections of polypeptide chain twists into speci c shapes for example a helix Tertiary structure Polypeptide tangles 0 Long polypeptide chain twists and folds into a complex tangled shape Quaternary Structure Multiple polypeptide interactions Denaturation 0 Protein uncoil and lose their shapes due to heat agitation acid 0 Lose their ability to function 0 Ex Hardening of an egg when it is cooked 3 Protein digestion Di estion roducts amino acids tri e tides di e tides Stomach Pepsin Stomach cells Break protein into smaller polypeptides proteases pancreas Break polypeptide into tri and dipeptides Small intestine Outer membrane Peptidase of small intestine Break most tr1 and d1pept1des 1nto am1no alt cells End products amino acids di and tripeptides 4 Functions of proteins a Structural i Building blocks of muscles blood and skin ii Maj or structural component of all cells b Catalysis Enzymes i EX digestive enzymes c Regulation Hormones i Messenger molecules that elicit response to restore normal conditions ii Some hormones are proteins EX Insulin and glucagon 5 Protein metabolism Excess amino acids from dietary protein intake can NOT be stored in the body they can be converted to body fats 6 High quality proteins vs low quality proteins a High quality proteins animal proteins soy protein b Low quality proteins plant proteins 7 Recommended intake AMDR 103 5 of calories from protein Translates into 50175 g protein RDA 08 gramskilogram of body weight for adults Found to kilogram conversion is 22 Divide weight in pounds by 22 to get kilograms Example Joe weighs 180 lbs Based on the RDA for protein how many grams of protein should he consume each day Divide body weight in pounds by 22 to get body weight in kilograms Answer 180 lbs22 818kg 818 kg 08gkg 65g Lipids l Lipids are a group of compounds that are insoluble in water 2 Fatty acids A chain of carbon and hydrogen atoms with an acid group COOH at the end saturated fatty acids No double bonds between carbon atoms monounsaturated one double bond polyunsaturated fatty acids two or more double bonds The omega number of an unsaturated fatty acid based on its chemical structure closest double bond to methyl group Essential fatty acids the body cannot synthesize o linoleic acid Omega6 veg oils meats o linolenic acid Omega 3 dark green vegetables veg oils axseed 3 Triglycerides Composed of three fatty acids attached to one glycerol Fats saturated fatssolid triglycerides from animals other than fish Oils unsaturated fats liquid triglycerides from plants or sh Fats and oils differ in their fatty acid components 0 Oils a high proportion of unsaturated fatty acids which have lower melting points 0 Fats mostly saturated fatty acids Partial hydrogenation of vegetable oils 0 double bonds are saturated to single bonds by adding hydrogen molecules 0 Food processing hydrogenation makes vegetable oils more solid by converting double bonds to single bonds e g margarine shortening Prolongs shelf life of food products Improves texture of foods During food processing hydrogenation most fats are partially hydrogenated The remaining double bonds change their configuration from cis to trans Partial hydrogenation can produce transfatty acidsfats Most transfats in our diet are from partially hydrogenated vegetable oils 000000 4 Phospholipids and sterols 5 Triglyc Phospholipids are the major constituents of cell membranes Most common sterol cholesterol Sterols cannot provide energy erides digestion Cholecystokinin CCK signals the gallbladder to release bile into small intestine to emulsify fat Bile acts as an emulsif1er so the enzymes can act on the fat Pancreatic lipases hydrolyze triglycerides into monoglycerides and fatty acids 6 Lipid transport lipoproteins 7 Health Vehicles for transporting lipids in blood stream Chylomicrons Deliver dietary lipids mostly triglycerides from SI to the rest of the body VLDL Deliver lipids synthesized in the liver mostly triglycerides to other tissues LDL Deliver lipids synthesized in the liver mostly triglycerides to other tissues HDL Picks up cholesterol from tissues and return it to liver for disposal Health implications of LDL and HDL i A high level of LDL can deposit a high level of cholesterol into the endothelia cells of the arteries 9 plaque a thick and hard deposit that can clog arteries atherosclerosis 1 If a clot blocks a narrowed artery blood ow is stopped and heart attack or stroke can result HDL can clear deposited cholesterol in arteries HDL lowers the risk of heart disease ii effects and recommendations Saturated fats amp trans fats increase CVD risk should decrease intake MUFAs amp PUFAs decrease CVD risk should increase intake especially w3 FAs Dietary Guidelines 2010 AMDR for fat 203 5 calories from fat Dietary Cholesterol lt3 00 mg per day Egg yolks up to l per day SFA lt10 of calories Replace with PUFAs and MUFAs TFA little or no Adequate Intake Al 510 of calories from linoleic acid 06l2 of calories from linolenic acid Energy metabolism 99 59 Metabolism The sum total of all the chemical reactions occurring in the body Anabolism Building up of body compounds require energy Catabolism break down of body compounds releases energy ATP Most of the energy released from macronutrients breakdown is captured in ATP The linking intermediate between energyyielding and energyrequiring chemical reactions in the body an energy reservoir a high energy compound Process of carbohydrate protein and fat metabolism in the body Carbs Glucose Proteins Amino acids Fats GlycerolFatty acids All three macronutrients can be broken down to Acetyl CoA and enter the m QM Q and H are produced from the TCA cycle Electron transport chain nal pathway of energy metabolism m is formed from oxygen and H and is synthesized Anaerobic oxidation of glucose glucose 9 pyruvate 9 lactate During prolonged fasting starvation acetyl CoA produced from fat breakdown is converted to ketone bodies for fuel 7 first in s wquot trAmInosaeIds gr will u A 4 gt waHAMH ATP rs telquot K31 i u glft l Fatty acids 0 All of the energy yielding nutrients protein carbohydrate and fat can be broken down to acetyl 00A 9 Acetyl CoA can enter the TCA cycle Acetyl CoA 9 0 Most of the reactions above release hydrogen atoms with their electrons which are carried by coenzymes to the electron transport chain 0 ATP is synthesized 6 Hydrogen atoms react with oxygen to produce water Cengage Learning 2013 6 Energy metabolism during feasting and fasting a Feasting Extra glucose 1 ii iii iV Stored as glycogen limited capacity After glycogen capacity is lled still extra glucose is converted to body m Extra fats l Stored as body fats unlimited capacity Extra amino acids V 1 NO capacity to store extra amino acids 2 Extra amino acids can be converted to body fats Excessive energy intake no matter in which form of macronutrients can lead to weight gain b Fasting i ii iii iv Shortterm fasting 1 day l Breakdown of glycogen to release glucose for energy Fasting for 25 days 1 Breakdown of body fats for energy Breakdown of lean tissues protein to release amino acids which are converted to glucose 1 gluconeogenesis Longterm fasting weeks or longer 1 Breakdown of body fats 2 Acetyl CoA converted to ketone bodies 3 Breakdown of lean tissues Metabolic Rate DECREASES
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