Ch6, 10-2-09

Ch6, 10-2-09 - Protein: Amino Acids Protein: Amino Acids...

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Unformatted text preview: Protein: Amino Acids Protein: Amino Acids Objectives Objectives What is protein? How are proteins made? How does the body break down protein? What about protein metabolism? Why do we need protein? How much Protein should we eat? What are good dietary sources of protein? What factors influence protein quality? How do we measure protein quality? Can vegetarians meet their protein needs? Definition Definition Proteins are made from 20 different amino acids, 9 of which are essential – A compound composed of carbon, hydrogen, oxygen, and nitrogen atoms – Nitrogen atoms give the name amino to the amino acids, the basic building blocks of proteins Amino Acids Amino Acids Amino Acids Amino Acids Essential amino acids Amino Acids Amino Acids – a.k.a indispensable amino acids – a.k.a dispensable amino acids – needs essential amino acid to make a conditionally essential amino acid – normally nonessential Nonessential amino acids Conditionally essential amino acids Proteins Proteins Amino acids linked end­to­end in variety of sequence to form thousands of different proteins – Peptide bond Bond that connects the acid end of one amino acid with the amino end of another forming a link in the protein chain Proteins Proteins Dipeptide: two amino acids bonded together Proteins Proteins Tripeptide – 3 amino acids bonded together Proteins Proteins Polypeptide – Many amino acids bonded together Proteins Amino acid sequences – Vary within proteins Ex: polysaccharide vs. protein Ex: string of G’s Proteins Proteins Shape dependent on amino acid sequence – Hydrophobic Repelled by water Tuck inside away from the water – Hydrophilic Attracted to water Fold outward towards the water Protein Protein shape and function Proteins Proteins Protein denaturation – Uncoiling and loss of shape, therefore inhibiting function – When subject to heat, acid, or conditions that disturb stability – Irreversible after certain point Protein Digestion Protein Digestion Mouth – Proteins are crushed and moistened – NO DENATURIZATION, NO BREAK DOWN Stomach – HCl – Pepsinogen → pepsin Proenzyme or Zymogen – An INACTIVE ENZYME Protein Digestion Protein Digestion Stomach – Pepsin Cleaves large polypeptides into smaller polypeptides and some amino acids Protein Digestion Protein Digestion Small intestine – Proteases: enzymes that hydrolyze protein Intestinal and pancreatic – Peptidases: digestive enzyme that hydrolyzes peptide bonds Tripeptidases Dipeptidases Endopeptidases Exopeptidases Protein Protein Digestion in the GI Tract Protein Absorption Protein Absorption Carriers Capillaries – Into intestinal cells – Used for energy or synthesis of necessary compounds – Take back to liver whatever is not used – Enzyme/amino acid supplements are not necessary Absorption misconceptions Proteins in the Body Proteins in the Body The synthesis of protein is determined by genetic information. Protein is constantly being broken down and synthesized in the body. Researchers measure nitrogen balance to study synthesis, degradation and excretion of protein Proteomics – The study of proteins is called Protein Synthesis Protein Synthesis Delivering the instructions – DNA mRNA tRNA – 2 major steps Transcription – mRNA being made from DNA Translation – mRNA directing sequence of AA and synthesis of proteins Protein Synthesis Protein Synthesis Protein Synthesis Protein Synthesis Protein Synthesis Protein Synthesis ...
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This note was uploaded on 10/31/2009 for the course HUN 1201 taught by Professor Razsaadat during the Fall '08 term at FSU.

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