1 Food /exercise diary or essay option-questions? -if consuming the recommended number of servings for each food group for one’s age and gender one is most likely meeting all of one’s dietary nutrient requirements. -hence no worries about consuming foods without a food label No discussion of pathology in the 2104 essay option- any questions on essay or dietary assessment option? 94/80 AA displacement

2 LECTURE 6A PROTEINS 9 Feb. 2015

3 a)Proteins defined p. 168 contain carbohydrate, hydrogen and oxygen just like lipids and carbohydrates but proteins also have nitrogen shape and hence function depends on amino acid side chains

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6 Amino acids P Amino definition Building blocks Non-essential Essential Conditionally essential

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8 Protein structure p considerable variety of proteins variety comes from lots of different shapes and hence functions of protein loss of shape-loss of function heat, acid, beating, chemically (e.g. urea) get easier digestion and occasionally colour change

9 IDATME of proteins and amino acids P Ingestion - oral, tube (whole protein, or protein hydrosylates or amino acids), IV (amino acids only) Digestion Stomach-acid and pepsin Small intestine lumen-oligopeptides,tri- and dipeptides, and amino acids formed Small intestine wall-tri- and dipeptides formed into single amino acids Issues of dietary enzymes and pre-digested proteins

10 IDATME of proteins and amino acids P Digestion qcMEAHY

11 IDATME of proteins and amino acids continued Animal proteins are generally very digestible and plant proteins are generally less digestible than animal proteins Proteins vary in their digestibility due to variable dietary protein structures as well as other food ingredients and hence accessibility to protein digestive enzyme active sites Complete plant proteins -soy - very digestible - close to many animal proteins’ digestibility -quinoa - about 10 % less digestible than soy

12 IDATME of proteins and amino acids continued Digestibility affects availability (WWFQ) of essential and non-essential and conditionally essential amino acids

13 IDATME of proteins and amino acids continued Absorption P. 185 Carriers

14 Transport Blood-amino acids alone or as part of proteins IDATME of proteins and amino acids continued

15 PROTEIN METABOLISM DNA to PROTEIN P E:\Media\Animations\chapter6\Protein_Synthesi s\0606.html

Fig. 6-7, p. 188

18 PROTEIN METABOLISM Proteins broken down to amino acids and amino acids then broken down to urea and water Also have synthesis of non-essential amino acids in the body Essential and non-essential amino acids and conditionally essential amino acids are made into proteins

19 PROTEIN EXCRETION Faeces- undigested protein and unabsorbed amino acids Urine- urea and water Sweat- metabolic water formed by amino acid catabolism Respiration- CO 2 and water from amino acid catabolism Saliva?-whole proteins

20 STRUCTURE IN THE BODY Primary Secondary Tertiary Quaternary Globular Fibrous Undone - heat, chemically, mechanically, pH

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23 PROTEINS ESSENTIAL OR NOT? Yes- functions

24 PROTEIN FUNCTIONS P CHAPERONES

25 PROTEIN FUNCTIONS CONTINUED ENZYMES proteases carbohydrases lipases

26 PROTEIN FUNCTIONS CONTINUED NUTRIENT AND STORAGE PROTEINS nutrient proteins ovalbumin casein storage proteins ferritin

27 PROTEIN FUNCTIONS CONTINUED TRANSPORT PROTEINS lipoproteins hemoglobin glucose transporters amino acid transporters sodium potassium transporter

28 PROTEIN FUNCTIONS CONTINUED CONTRACTILE OR MOTILE PROTEINS actin myosin

29 PROTEIN FUNCTIONS CONTINUED STRUCTURAL PROTEINS collagen elastin keratin

30 PROTEIN FUNCTIONS CONTINUED DEFENCE PROTEINS antibodies fibrinogen thrombin

31 PROTEIN FUNCTIONS CONTINUED REGULATORY PROTEINS insulin parathyroid hormone

32 PROTEIN FUNCTIONS CONTINUED RECEPTOR PROTEINS insulin LDL receptor

33 PROTEIN FUNCTIONS CONTINUED SIGNALLING PROTEINS insulin sets off signalling cascade for glycogen synthesis

34 PROTEIN FUNCTIONS CONTINUED Energy

35 In summary proteins: Bind (B) Catalyse (C) Build (B) PROTEIN FUNCTIONS CONTINUED