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

LECTURE 6A PROTEINS 10 Oct. 2018

Proteins defined but proteins also have nitrogen 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

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

Protein structure 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

Stomach-acid and pepsin Small intestine lumen-oligopeptides,tri- and  IDATME of proteins and amino acids 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  

IDATME of proteins and amino acids Digestion http://wowzahttp.cengage.com/digital-production/nutrition/06060.mp4  

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

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

IDATME of proteins and amino acids continued Absorption -carriers

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

PROTEIN METABOLISM DNA to Protein   DNA to Protein http://wowzahttp.cengage.com/digital-production/nutrition/0607.mp4

Figure 6.7: Animated! Protein Synthesis. Fig. 6-7, p. 188

Figure 6.7: Animated! Protein Synthesis.

  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

  PROTEIN EXCRETION Faeces- undigested protein and unabsorbed amino acids Urine- urea and water Sweat- metabolic water formed by amino acid catabolism Respiration- CO2 and water from amino acid catabolism Saliva?-whole proteins

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

PROTEINS ESSENTIAL OR NOT? Yes- functions

PROTEIN FUNCTIONS P. 175-178 CHAPERONES

PROTEIN FUNCTIONS CONTINUED ENZYMES proteases carbohydrases lipases

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

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

PROTEIN FUNCTIONS CONTINUED CONTRACTILE OR MOTILE PROTEINS actin myosin

PROTEIN FUNCTIONS CONTINUED STRUCTURAL PROTEINS collagen elastin keratin

PROTEIN FUNCTIONS CONTINUED DEFENCE PROTEINS antibodies fibrinogen thrombin

PROTEIN FUNCTIONS CONTINUED REGULATORY PROTEINS insulin-part of blood glucose level control parathyroid hormone-helps control calcium and phosphorous levels in the body

PROTEIN FUNCTIONS CONTINUED RECEPTOR PROTEINS insulin LDL receptor

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

PROTEIN FUNCTIONS CONTINUED Energy

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