nutrisci #2 - Proteins 01:24 Structure:

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Proteins 01:24 Structure:  Proteins contain carbon, hydrogen, and oxygen o Nitrogen is distinguishing character (only macronutrient w/ nitrogen) o Joined together by peptide bonds  peptide= short chain of amino  acids Proteins have hundreds or thousands of amino acids o Any particular protein has same sequence of Amino acids  Sequence is carried in DNA 1 gene  1 protein (or a fraction) Digestion of Protein Beings in stomach  stomach acid denatures protein and exposes it to  protease protease breaks down amino acids in small intestine Functions Body is largely made up of protein o muscle, connective tissue, bone matrix, and cell membrane blood constituents, blood clotting factors, blood transport proteins lipoproteins: transports far in water based blood maintain fluid balance in body attract and retain fluid in bloodstream (osmosis) proteins attract water through osmatic pressure  protein deficiency, fluid leaks out of  blood stream into gut acid base balance- buffer acidity
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most proteins are enzymes- control and facilitate reactions peptides used in hormones affect cells throughout the body neurotransmitter  synapse transmit- complex system gives you control three amino acids are neurotransmitters or precursors (make into final  product) Immune system- foreign protein called antigens- produce antibodies Deficiency decreases immune response Energy source: 4 kcal/gram 10-15% of calories gluconeogenesis (glucose synthesis from amino acids) o maintain blood sugar- brain= obligate glucose user Protein requirement RDA’s- age, body, weight Males: 63 g/day, and Females: 44 g/day Protein needs met by 1200 kcals of typical diet o Adequate kcals  adequate protein Higher needs in Children: up to 2.2  Growing people Pregnancy  High active- u to 1.5 g/ks Timing of protein is important
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Average intake in US  males 90 g/day, females 70 g/day Excess protein gets turned into energy Stored as fat Remove nitrogen urea urine Diaretic affect- produce more urine to wash out protein Increases risk of kidney stones Can cause bone demineralization- lose minerals Emphasize lean proteins- no exclusive use Milk also high in protein protein quality essential amino acids: 9 o cant be synthesized, must be in diet biological value limiting AA stops protein synthesis Biological Value: nitrogen retained/nitrogen consumed Eggs are good for protein Animal proteins High biological value- complete High fat, high saturated fat Low in fiber Plant protein (lower quality)
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Grains, legumes, beans, soy products, vegetables, nuts, seeds
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This note was uploaded on 03/07/2012 for the course NUTRI 132 taught by Professor Anderson during the Spring '11 term at Wisconsin.

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nutrisci #2 - Proteins 01:24 Structure:

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