Nutri Sci ch, 5 - Brian Oliver Chapter 5 Protein...

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Brian Oliver February 12, 2008 Chapter 5: Protein Introduction 1. “protein” comes from the Greek word protos (first) 2. the best food used to be the one highest in protein 3. protein is the nutrient with the highest recommended dietary allowance An Ecological Perspective 1. Protein is different from Carbohydrates and Fat because it has Nitrogen a. Nitrogen: essential to the structure of amino acids b. Farmers add nitrogen to soil to ensure better yields 2. Legumes pull nitrogen out of the air a. Legume: member of the plant family; pulls nitrogen out of the air to produce high-protein seeds b. Legumes are higher in protein than other plants c. They aren’t dependent on the soil alone for protein 3. nitrogen in soil is taken up by plants and incorporated into protein a. when plants die, their nitrogen goes into the soil b. this soil is eaten by herbivorous animals (dependent on plant protein) c. animals absorb nitrogen and return it to soil in feces d. plant nitrogen helps animals make their own protein e. when animals die, they return their nitrogen to the soil, or are eaten by other animals 4. nitrogen composes 78% of the air we breathe 5. our bodies don’t change it 6. once nitrogen returns to the soil, it is released into the air by bacteria, and the process starts again Structure 1. Amino Acids a. The proteins in our bodies are made of 20 different amino acids b. Amino acids are composed of carbon, hydrogen, oxygen, and nitrogen (sometimes sulfur) i. All nitrogen in food is protein ii. Nitrogen isn’t found in carbs and fat, only protein iii. Nitrogen is found in an amine c. When protein is used for energy, its nitrogen becomes waste, or urea i. Kidneys make this into urine 2. Peptides a. Amino acids are joined by peptide bonds b. Peptide: chain of amino acids (dipeptides or polypeptides)
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c. Insulin is composed of 51 peptides 3. Proteins a. Protein: long chains of amino acids b. Amino acids are in specific sequences depending on the protein i. Sequence: order in which amino acids appear in a protein, affecting its physical and chemical properties c. DNA carries sequences of proteins in the genes i. Each gene is a “recipe” for a protein ii. One gene specifies one protein, or a part of a protein 4. Complex Structure a. The sequence of amino acids is the primary layer of organization in a protein b. Amino acid side chains can either attract or repel
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This note was uploaded on 04/06/2008 for the course NUTRI SCI 132 taught by Professor Anderson during the Spring '08 term at University of Wisconsin.

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Nutri Sci ch, 5 - Brian Oliver Chapter 5 Protein...

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