Chapter 6 Nutrition powerpoint
Chapter 6 Nutrition powerpoint 10144
Popular in Intro to Nutrition
verified elite notetaker
Popular in Nutrition and Food Sciences
verified elite notetaker
This 65 page Class Notes was uploaded by Nnenne Asi on Wednesday March 2, 2016. The Class Notes belongs to 10144 at University of North Carolina - Greensboro taught by Mrs. Laurie Allen in Winter 2016. Since its upload, it has received 19 views. For similar materials see Intro to Nutrition in Nutrition and Food Sciences at University of North Carolina - Greensboro.
Reviews for Chapter 6 Nutrition powerpoint
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/02/16
Chapter 6: Proteins & Amino Acids Introduction Proteins A class of nutrients that include molecules made up of one or more intertwining chains of amino acids Contain carbon, hydrogen, oxygen, and nitrogen Play crucial roles in all biological processes Large, complex molecules found in the cells of living things Help facilitate many of the body’s functions Protein Functions Structural proteins Enzymes Cells Assist biochemical Cell Membrane reactions Organelles Most chemical reactions Cell Fluid (cytoplasm) in the body require enzymes Body Parts Skin Transport other Hair proteins in blood and Ligaments across membranes Tendons Protein Functions Immunity/safety Movement Skin—barrier from Skeletal muscles bacteria Smooth muscles Blood clotting in case Hormones of injury Regulate fluid Antibodies protect the body from foreign balance Maintain proper acidity invaders i.e. vaccines stimulate of blood these to improve Energy immunity against disease Protein Functions Protein Functions Sources of Protein Animal products Properties Meats High in B vitamins, Beef, poultry, pork & fishiron, zinc, and calcium Eggs Dairy Sources of Protein Plant products Grains Nuts Almonds, walnuts, pecans, cashews, pistachios, etc. Legumes Starchy seed of a plant; peas, peanuts, beans, soybeans and lentils Properties Low amounts of iron, zinc, calcium and B vitamins High in fiber, phytochemicals, and unsaturated fats The Structure of Protein:Amino Acids Amino acids are the building blocks of proteins Amino acids contain Carbon, hydrogen, acid group, amino group (nitrogen containing), and a side chain Amino Acids There are hundreds of proteins known, but only 20 amino acids commonly occur naturally Nine are essential The body cannot make and must come from the diet Eleven are nonessential The body can make them by using nitrogen from essential AA and pieces of CHO and fats © 2012 John Wiley & Sons, Inc. All rights reserved. Essential vs. non-essential amino acids Essential/indespensible: Cannot be made in the body so “essential” to eat them If one is missing, body proteins are broken down to make new proteins Non-essential/despensible: Body can make them from other proteins so not essential to eat them Conditionally essential-When a nonessential amino acid becomes essential under certain circumstances, it is known as conditionally © 2012 John Wiley & Sons, Inc. All rights reserved. What a scientist sees © 2012 John Wiley & Sons, Inc. All rights reserved. Amino acids link to form proteins 2 aa = dipedtide 3 aa = tripeptide Many aa= polypeptide © 2012 John Wiley & Sons, Inc. All rights reserved. Protein folding Amino acids interact to form the 3-dimensional structures of proteins Structures of proteins determines their functions If protein structure is changed, then protein function may change + - + - © 2012 John Wiley & Sons, Inc. All rights reserved. The Shape of Proteins The shape of a protein is essential to its function The elongated shape of the protein collagen gives strength to tendons and ligaments The spherical shape of the protein hemoglobin contributes to the proper functioning in red blood cells The linear shape of the protein in muscles allows the muscles to change shape during contraction Protein Denaturation Protein Denaturation Denaturation—alteration of a protein’s three-dimensional structure due to Agitation The stiffening of egg whites when they are whipped Heat Processing, cooking (hardening of an egg when it is cooked), fever Acidic and basic conditions Stomach; the curdling of milk when acid is added Acidosis and alkalosis (low/high blood pH) Heavy metals (mercury, gold, lead) Alcohol Detergents Proteins uncoil; after this occurs, the protein no longer functions as it naturally did before Application Insulin is a protein. Why do diabetics need to inject insulin rather than take it orally? © 2012 John Wiley & Sons, Inc. All rights reserved. Protein Digestion © 2015 John Wiley & Sons, Inc. All rights reserved. Digestion and Absorption Mechanical digestion begins in the mouth when chewing breaks down the food Chemical digestion begins in the stomach Hydrochloric acid (HCl) denatures (uncoils) proteins HCl activates pepsinogen to pepsin (enzyme) Pepsin breaks peptide bonds leaving shorter polypeptides Chemical digestion continues in the small intestine Pancreatic enzymes and enzymes in the microvilli of the intestine further break down polypeptides for absorption The majority of protein digestion occurs here Digestion and Absorption Single amino acids, dipeptides and tripeptides can be absorbed into the mucosal cells of the small intestine This uses different transport systems and amino acids can compete for absorption Dipeptides and tripeptides are further broken down into single amino acids Single amino acids then pass into the blood and are brought to the liver Protein absorption The purple amino acids are absorbed by the same transport system as the green amino acids. If you consume a sports drink that is supplemented with the green amino acids what will happen to the absorption of the purple ones. a)nothing b)the larger amount of green ones will limit the absorption of the purple ones c)the small amount of the purple ones will be absorbed first d)both will be absorbed equally because the body needs them © 2012 John Wiley & Sons, Inc. All rights reserved. Amino acid pool © 2012 John Wiley & Sons, Inc. All rights reserved. Amino acid pool Amino acid pool: amino acids available for use in the body From the diet or breakdown of body proteins Used to make other proteins or chemicals (for example: DNA, RNA, histamine, etc.) Used to provide energy or make glucose or fatty acids © 2012 John Wiley & Sons, Inc. All rights reserved. Amino acids link to form proteins We obtain amino acids from eating plant and animal foods. Our bodies reassemble the amino acid building blocks into our body proteins. © 2012 John Wiley & Sons, Inc. All rights reserved. Synthesizing Proteins The instructions for making proteins are contained in the genes in the nucleus of the cell Genes—a length of DNA that contains the information needed to synthesize a polypeptide chain Regulating Protein Synthesis The types of proteins made and when they are made are carefully regulated by gene expression Gene expression—the process by which cells use genes to make proteins Not all genes are expressed in all cells at all times Only the proteins needed are made at any given time Gene expression is influenced by Genetic background Nutrients Protein Synthesis The process of protein synthesis involves two steps Transcription Translation Transcription Transcription—a stretch of DNA (in the nucleus) is used as a template to make a strand of RNA (ribonucleic acid) known as messenger RNA (mRNA) After this, the mRNA strand crosses the nuclear membrane into the cytoplasm of the cell, taking the coding instructions with it Translation Translation—the mRNA attaches itself to one of the ribosomes (protein-making machine) mRNA specifies the sequence in which the amino acids line up for synthesis of a protein Transfer RNA (tRNA) collects amino acids from the cell fluid and brings them to the mRNA Each of the 20 amino acids has a specific tRNA Once the protein is made, tRNA is released to be recycled and used again Protein Synthesis © 2012 John Wiley & Sons, Inc. All rights reserved. Genes contain instructions for proteins Amino Acid A is the limiting Amino Acid © 2012 John Wiley & Sons, Inc. All rights reserved. Gene mutations Changes in gene sequence can change the sequence of the amino acids in a protein Changes in (amino acid) sequence can change how a protein folds and change its structure Changes in protein structure can change protein function + - - © 2012 John Wiley & Sons, Inc. All rights reserved. Think critically Sickle cell anemia is an inherited disease caused by an abnormality in the gene for the protein hemoglobin. It causes red blood cells to take on a sickle shape. Sickle cell hemoglobin differs from normal hemoglobin by one amino acid. Why might this difference change the shape of the hemoglobin? Do you think sickle-shaped red blood cells can travel easily through narrow capillaries? How might this disorder affect the ability to get oxygen to the body’s cells? © 2012 John Wiley & Sons, Inc. All rights reserved. Concept check Amino acids are linked together: a)During translation b)In the nucleus c)When DNA is made from RNA d)During transcription © 2012 John Wiley & Sons, Inc. All rights reserved. Concept check Building blocks of proteins are: a)nucleotides b)amino acids c)DNA and RNA d)codons © 2012 John Wiley & Sons, Inc. All rights reserved. Using Proteins Amino acids from the diet are used to make proteins and nitrogen-containing molecules Extra amino acids cannot be stored Extra amino acids are used for energy or stored as fat Using Proteins for Energy When we do not consume enough calories to meet needs, body proteins are broken down since amino acids are not stored Deamination removes amino group (NH ) 2 Produces urea which is excreted in urine Carbon, hydrogen, and oxygen can be broken down to produce ATP or used to make glucose or fatty acids Using Proteins for Energy PROTEIN IN HEALTH AND DISEASE © 2012 John Wiley & Sons, Inc. All rights reserved. Protein-Energy Malnutrition (PEM)/ Protein Energy Undernutrition A condition characterized by loss of muscle and fat mass and an increased susceptibility to infection that results from the long-term consumption of insufficient amounts of energy and/or protein to meet the body’s needs Types Kwashiorkor—pure protein deficiency Marasmus—overall energy deficiency © 2015 John Wiley & Sons, Inc. All rights reserved. Protein-Energy Malnutrition (PEM) © 2015 John Wiley & Sons, Inc. All rights reserved. © 2012 John Wiley & Sons, Inc. All rights reserved. Protein allergies When a protein is absorbed intact, the immune system can recognize it as an antigen and start cellular reactions The second time immune system detects that same allergen (allergy-causing antigen), there is an allergic reaction Major food allergens: milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat © 2012 John Wiley & Sons, Inc. All rights reserved. High-protein diets Usually: high in animal proteins with high saturated fat and cholesterol and low in fiber low in grains, fruits, and vegetables high in calories and fat Could lead to increased risk of heart disease, cancer, obesity, and diabetes © 2012 John Wiley & Sons, Inc. All rights reserved. Protein excess Increased urea output Increased demands on the kidneys Increased loss of water from the body Possible increased loss of calcium Increased risk of kidney stones MEETING PROTEIN NEEDS © 2012 John Wiley & Sons, Inc. All rights reserved. Protein on food labels © 2012 John Wiley & Sons, Inc. All rights reserved. Food sensitivities and intolerances Do not involve the immune system Trigger various symptoms after consumption Examples: MSG symptom complex or Chinese restaurant syndrome © 2012 John Wiley & Sons, Inc. All rights reserved. Nitrogen balance Nitrogen intake equals nitrogen loss Maintaining body protein and weight Negative nitrogen balance: more nitrogen lost than consumed From illness, injury, or decreased consumption Positive nitrogen balance: more nitrogen consumed than lost From growth, pregnancy, or weight training © 2012 John Wiley & Sons, Inc. All rights reserved. Nitrogen balance © 2012 John Wiley & Sons, Inc. All rights reserved. Protein quality High-quality, or complete dietary, proteins Contain all amino acids to meet body’s needs More easily digested Animal proteins and soy Incomplete proteins Lower in one or more essential amino acids Most plant proteins Use complementary proteins © 2012 John Wiley & Sons, Inc. All rights reserved. © 2012 John Wiley & Sons, Inc. All rights reserved. Complementary proteins © 2012 John Wiley & Sons, Inc. All rights reserved. Protein Complementation What are some other complementary proteins? Rice and beans (Mexico/S. America) Lentils and rice (India) Chickpeas and rice (India) Hummus and bread (Middle East) Bread and peanut butter (U.S.) Complementary foods do not need to be eaten at the same meal, so eating a variety of plant foods throughout the day can still © 2015 John Wiley & Sons, Inc. All rights reserved. Types of vegetarian diets Semivegetarian: Excludes red meat but may include fish and poultry, as well as dairy products and eggs Pescetarian: Excludes all animal flesh except fish Lacto-ovo vegetarian: Excludes all animal flesh but includes eggs and dairy products Lacto vegetarian: Excludes animal flesh and eggs but includes dairy products Vegan: Excludes all food of animal origin © 2012 John Wiley & Sons, Inc. All rights reserved. Vegetarian diets Reasons to be vegetarian: Limited land and/or resources Health Religion Personal ethics Environmental concerns © 2012 John Wiley & Sons, Inc. All rights reserved. Benefits vs. Risks Benefits Risks Lower body weight Protein deficiencies Increased fiber When complementary proteins are not used Diet more filling Reduced risk of When there are increased needs chronic disease Decreased obesity Vitamin/mineral deficiencies Less saturated fats Higher values of fiber, B12 and vegans Calcium vitamins, minerals, antioxidants, Iron/zinc phytochemicals Meeting dietary needs with a vegan diet © 2012 John Wiley & Sons, Inc. All rights reserved. Protein Requirements Protein recommended daily allowance 0.8 g/kilogram of body weight for adults With more weight, more protein is needed for maintenance and repair 70 kg (154 lb) adult = 56 g of protein/day Average consumption = 70 g of protein/day Higher needs in infants, during pregnancy and lactation (breast feeding), after injury, and in for athletes Pregnant/lactating women: add 25 g of protein/day © 2012 John Wiley & Sons, Inc. All rights reserved. Calculate 100 pound adult weight in kilograms equals weight in pounds x0.45 kg/lb Protein RDA = 0.8 g/kilogram of body weight How much protein does this person need? © 2012 John Wiley & Sons, Inc. All rights reserved. Protein dietary recommendations Acceptable Macronutrient Distribution Range for protein:10% to 35% of calories Dietary Guidelines 2010 recommend that we choose a variety of protein foods, including seafood, lean meat and poultry, eggs, beans, soy products, and unsalted nuts and seeds © 2012 John Wiley & Sons, Inc. All rights reserved. Choosing Proteins Wisely
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'