Lecture 3.1 - Proteins PDF

NATS1560: UNDERSTANDING FOOD MACRONUTRIENTS PART 3: PROTEINS Angela Cope [email protected] Learning Objectives: To explain the molecular composition of proteins and their “building blocks,” the amino acids To explain the diff erence between essential, non-essential, and conditionally essentia...

NATS1560: UNDERSTANDING FOOD MACRONUTRIENTS PART 3: PROTEINS Angela Cope [email protected] Learning Objectives: To explain the molecular composition of proteins and their “building blocks,” the amino acids To explain the diff erence between essential, non-essential, and conditionally essential amino acids To list the diverse functions of proteins in the body  PROTEINS Proteins are polymers composed of amino acids Amino acid = molecule composed of an amine (-NH 2 ), a carboxylic acid (-COOH), and a “side chain” -the side chain is diff erent in each amino acid Polypeptide: sequence of amino acids Protein: polypeptide folded into a specifi c complex shape Every protein is characterized by its specifi c sequence of amino acids 3 Protein Folding: There are four stages of protein folding Fun Fact: You used to be able to set your PS3 to use its unused processor power to fold proteins! AMINO ACIDS Twenty amino acids are coded by DNA and used by living organisms Essential: the human body needs to obtain them from food Conditionally Essential amino acids: the human body may need to obtain them from food under certain conditions Non-essential: the human body can create them endogenously 5 THE FUNCTIONS OF PROTEINS structure (e.g., keratin and collagen) enzymes (e.g., lactase) some hormones ( e.g., somatotropin, insulin) muscle contraction (actin and myosin) immune system (antibodies) transport and cellular communication ( e.g., hemoglobin) energy 6  Complete sources of essential amino acids: eggs, meat, fi sh, milk and milk products, soybeans, quinoa, amaranth FOOD Incomplete sources of amino acids: legumes or pulses, grains, nuts, seeds, some vegetables, SOURCES and some fruits OF Combinations of ingredients in dishes PROTEINS and diets can provide the full assortment of essential amino acids. 7  What are the “building blocks” of proteins? A) Amino Acids REVIEW 1: B) Triglycerides C) Glycine D) Oligosaccharides 8  What is the diff erence between essential and non-essential amino acids? A) Essential amino acids can be made by the body, non-essential amino acids must be obtained from food B) Non-essential amino acids can be made by the body, essential amino acids must be obtained Review 2: from food C) Essential amino acids are amino acids that form alpha helixes, non-essential amino acids form Beta sheets D) Essential amino acids make proteins, non- essential amino acids form cholesterols E) None of the above  What are functions of proteins in the body? A) Structure B) Enzymes like lactase Review 3: C) Hormones like somatotrophin D) Muscle contraction E) All of the above  What are the main food sources of proteins? A) Breads, pasta, and grains B) Legumes, beans and peas Review 4: C) Meats and eggs D) Seed and Fish oils E) B and C