Nutrition FINAL COPY 2 - Exam II review sheet PROTEINS 1....

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Exam II review sheet PROTEINS 1. Proteins are made of amino acids (contain carbon, hydrogen, oxygen, and nitrogen ) 2. 20 different amino acids (essential, nonessential); Recognize names. Essentials : Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine Nonessentials: Alanine Arginine Asparagine Aspartic acid Cysteine Glutamic acid Glutamine Glycine Proline Serine Tyrosine Body can manufacture non-essential amino acids with enough kcal, protein in diet - Body can make nonessential amino acids with a nitrogen to form the amino group and fragments from carbs or fat to form the rest of the structure Essential amino acids must be obtained through the diet – body CANNOT sythesize 3. When proteins are subjected to acid, heat, and strong mechanical action they uncoil or denaturation - Denaturation makes the proteins UNABLE to function 4. Digestion / Absorption Stomach o Name enzyme responsible for protein breakdown - PEPSIN o Functions of HCl – Kills bacteria Inactivates salivary amylace Activates PEPSIN, which is the gastric enzyme that breaks down proteins Denatures proteins (due to pH change) Small intestine o Name enzymes responsible for protein peptides amino acids. o Polypeptides enter small intestine > pancreatic and intestinal proteases (enzymes) break proteins (polypeptides) into peptide chains & peptidase enzymes on membrane surfaces of intestinal cells split peptides into single amino acids o Absorption: Into which circulatory system do amino acids enter after absorption? Most proteins are broken down into amino acids before absorption Absorbed in vascular (blood) system
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Exam II review sheet 5. Metabolism: Amino acids Protein synthesis – All essential / nonessential amino acids needed at time of synthesis DNA/ RNA are responsible for all protein synthesis, without RNA and DNA proteins would not be synthesized Energy Amino acids are deaminated when used for energy If NH2 to be discarded converted to ammonia then urea by the liver; Urea is a product of amino acid breakdown Carbon fragments are then used in energy metabolism pathways (glycolysis, TCA cycle, Electron transport chain) Excess kcal in diet (protein needs met) – production of fat Deficiency of kcal in diet – broken down for energy Amino acids can be used to synthesize non-protein compounds Niacin Neurotransmitters Melanin 6. Describe functions of proteins: Structural: collagen, protein deposition o Collagen (protein) makes up most of your connective tissue Tendon (muscle-to-bone) Ligament (bone to bone) Scars that connect torn tissue o Proteins create new cells to replace old ones (hair, nails, GI tract) Enzymes o Enzymes are catalysts that act by breaking down or building up a substance o They remain unchanged no matter how many reactions they facilitate Hormones: examples are insulin, glucagons o Some hormones are proteins (examples listed above) o Hormones are released by various endocrine glands and are carried to
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This test prep was uploaded on 04/16/2008 for the course NTR 311 taught by Professor Lydiasteinman during the Fall '08 term at University of Texas at Austin.

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Nutrition FINAL COPY 2 - Exam II review sheet PROTEINS 1....

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