Cl a ss N o t e s O c t o b e r 7 2 013 Nutrition Concepts October 7 2013 Protein Synthesis DNA makes RNA makes protein RNA is the copy of the code mRNA messenger RNA copy of DNA tRNA transfer RNA vehicles for amino acids that are used to make a protein Ribosome protein making machine mRNA is the supervisor in the ribosome that tells to put in which order to make a protein DNA makes RNA makes PROTEIN Step 1 Transcription DNA makes mRNA mRNA attaches to a ribosome Step 2 Translation mRNA speci es the sequence of the amino acids Protein Synthesis Review The code to make a protein is carried by a strand of mRNA The process by which mRNA is made from a DNA template is transcription A ribosome is a structure upon which amino acids are sequenced into proteins The process where the ordering or sequencing of amino acids by the mRNA is called translation Protein Expression DNA makes RNA makes Protein Gene expression de nitions Process by which a cell converts the genetic code into RNA and protein When a cell makes a protein under direction of a gene Cells regulate gene expression based on Type of protein needed How much how fast Nutrigenomics the foods we eat in uence gene expression Date Oct o be r 7 2 013 Class N ut r it io n Co n ce p t s Page On e structural materials enzymes hormones regulators of uid balance etc Roles of Proteins Proteins as Enzymes Enzymes are proteins that facilitate chemical reactions Catalysts but are not changed in the process Some Are catabolic enzymes break down i e lipase Are anabolic enzymes build up i e building of bones Transform i e amino acids into glucose to energy during starvation red blood cells and brains can only use glucose Proteins as Hormones Some hormones are proteins Hormones are messengers Released in response to changes challenges Transported in blood to target tissues Example Insulin is released from the PANCREAS in response to HIGH BLOOD SUGAR The insulin sends the message to increase uptake of glucose from the blood to glycogen storage in the liver Glucagon is released from the PANCREAS in response to LOW BLOOD SUGAR The glucagon sends the message to increase release of glucose to the blood from glycogen storage in the liver Proteins as Regulators of Fluid Balance Proteins help maintain uid balance the proper types and amounts of uid in each compartment of the body Normally proteins are found in cells not in between interstitial spaces Reasons proteins leak out ALL LOW PROTEIN after leak out attract water 1 Excessive protein losses from in ammation or critical illness 2 inadequate protein synthesis liver disease 3 inadequate dietary intake of protein Proteins attracts water so leaking of proteins into spaces between cells causes edema swelling Page 2 Proteins as buffers Acid solution contains abundance of H which have a positive charge Proteins have a negative charge and attract or release H to maintain pH and prevent Denaturation of proteins in Acidosis higher than normal acidity in blood and body uids Alkalosis higher than normal alkalinity base in the blood and body uids Proteins as antibodies Antibodies army Proteins as antibodies defend the body against disease large proteins of the blood and body uids that the immune system makes in response to attack by foreign invaders Antibodies have speci city Immunity memory Roles of Proteins Review Proteins can act as hormones which act as a messenger Body proteins attract water causing edema swelling and hydrogen thus acting as a buffer This actions prevents acidosis and alkalosis and the resulting denaturation of protein Proteins can act as transporters carrying proteins through the body or across cell membrane in which case they act as pumps An example of this is the transport of sodium and potassium to maintain the appropriate concentrations of these minerals inside and outside of the cell The body produces giant protein molecules called antibodies to inactivate ght against foreign invaders or antigens Review of Protein Metabolism In each cell proteins are continuously made broken down Protein Turnover degradation and synthesis of protein Page 3 Releases amino acids what that does product of protein turnover Preview of Protein Metabolism Amino acid pool very short term storage Supply of amino acids from Broken down protein Dietary protein Remains fairly constant if not in diet body can go to that pool Used for Protein synthesis Energy nitrogen removed from amino acids can make glucose from the amino acids and use for energy Nitrogen balance amino group and that nitrogen in all proteins for adults The amount of nitrogen consumed as compared with the amount of nitrogen excreted in a given period of time times of growth Zero nitrogen balance or nitrogen equilibrium Nitrogen in nitrogen out Positive nitrogen balance Nitrogen intake Nitrogen excretion take in more nitrogen than excreting using that nitrogen body says I need more protein to exercise in pregnancy Examples Infants pregnant women children athletes adolescents someone recovering from protein de ciency Negative nitrogen balance Nitrogen intake Nitrogen excretion Examples burn victims stress injuries Proteins are used to make other compounds such as Neurotransmitters epinephrine Melanin brown pigment Thyroxin helps balance our metabolic rate Niacin and Serotonin Protein can be broken down for energy glucose No storage site for protein we have to go to the muscle lean body tissue Carbohydrates liver glycogen Fats Triglycerides in adipose tissue Starvation over time Body breaks down lean body tissue muscle and fat Adequate intake of carbohydrates and fats is protein sparing Page 4 Proteins in excess can be used to make fat high protein diets can still contribute to weight gain by being turned into fat When energy and protein exceed needs and carbohydrate intake is adequate Can contribute to weight gain Deaminating amino acids can make the nonessential from the essential Removal of nitrogen containing amino group Products Ammonia in the body not good Keto acid Using amino acids to make proteins and nonessential amino acids If body needs Essential amino acid Break down proteins to obtain it Nonessential amino acid because you can make them in the body production of this is transamination process Make from keto acids MOVING of the amino group to make a different amino acid a nonessential Make nonessential acids through transamination but that creates ammonia so needs to be lter which creates urea which needs to be excreted Other
View Full Document
Unlocking...