Lennon Edwards Summer 2015 NTDT 200 194 195 EXAM 2 REVIEW SHEET The exam contains 64 multiple choice questions The exam is worth a total of 80 points Chapter 5 Lipids Define and identify the 3 types of lipids and their general make up Triglycerides even chain of carbon atoms with hydrogen atoms attached methyl and acid groups only soluble in fat 3 triglycerides attach to glycerol in condensation reactions phospholipids watery fluid glycerol heads with fatty acid tails contain a phosphate group soluble in water and fat and sterols compounds with 4 carbon ring structure and a variety of side chains attached Saturated solid at room temp generally of animal origin vs unsaturated fats fatty acids monounsaturated and polyunsaturated omega 3 6 trans fat fatty acids with hydrogens on opposite sides of double bond acts more like saturated fat in the body how structure influences characteristics of the fats general structure 0 double bonds for saturated fatty acid 1 for oleic monosaturated 2 for linoleic polyunsaturated 3 for linolenic omega 3 fatty acid polyunsaturated fatty acid examples of each type of fatty acid stearic acid is an 18 carbon saturated fatty acid unsaturated fatty acids lack hydrogen atoms and have at least one double bond called the point of unsaturation EX oleic acid is an 18 carbon monounsaturated fatty acid and linoleic acid is omega 6 fatty acid and is an 18 carbon polyunsaturated fatty acid food sources of the different types of fat saturated found in most animal fats oleic acid in olive and canola oils linoleic acid in sunflower safflower corn and soybean oils and linolenic found in soybean and canola oils flaxseed walnuts influence on health Process of hydrogenation what is it health implications protects from rancidity hydrogenation adds back hydrogens to unsaturated fatty acids and produces trans fat protects against oxidation and alters texture Roles of phospholipids example of one soluble in fat and water most common one is lecithin used as emulsifiers allow fat and water to mix transport of lipids across cell membranes Roles of sterols examples of them starting material for bile acids sex hormones adrenal hormones vitamin D and structural component of cell membranes Where fat digestion starts the mouth enzymes involved lingual lipase released in mouth but active in stomach cholecystokinin CKK signals gallbladder to release bile hydrolysis of triglycerides involves pancreatic and intestinal lipases role of bile emulsifies fats brings fat into the water converts large fat globules into small droplets that repel each other and makes fat digestion more efficient formation of micelles large lipids such as monoglycerides and long chain fatty acids combine with bile to form micelles how are long chain vs short and med chain fatty acids digested differently glycerol and short medium chain fatty acids go directly to bloodstream large lipids combine with bile salts to form micelles Know the lipoproteins chylomicrons largest least dense lipoprotein transport diet derived in fat primarily TG to cells of body VLDL made by liver to transport lipids primarily TG to cells LDL derived from VLDL as TG removed primarily chol HDL transports cholesterol back to liver 50 protein and 50 lipid what are they roughly made of what they do and any health implications associated with LDL and HDL high blood LDL increases risk of heart disease and high blood HDL decreases risk of heart disease cholesterol in both is the same but their difference is found in the proportions and types of lipids and proteins within them Know essential fatty acids Linoleic acid comes from veggie oils and meats and Linolenic acid 18 carbon linoleic acid used to make longer omega 6s makes arachidonic acid AA deficiency of 1 Lennon Edwards Summer 2015 linoleic would cause AA to become essential and 18 carbon linolenic acid is used to make longer omega 3s makes EPA and DHA important for normal growth and development of the brain and eyes and linolenic may also play a role in heart disease prevention Lipoprotein lipase enzyme that hydrolyzes TG and directs their parts into cells and hormone sensitive lipase enzyme inside adipose cells hydrolyzes TG for energy Fat requirements AMDR 20 35 of energy intake for total fat 10 for saturated fat keep trans fat as low as possible and 300mg cholesterol Chapter 6 Proteins Make up of amino acids and proteins Carbon hydrogen oxygen and nitrogen Amino acids are the building blocks of proteins with an amino group an acid group and a side group that varies Essential vs nonessential amino acids conditionally essential 20 amino acids 11 nonessential 9 essential nonessential body can synthesize itself dispensable essential must be consumed in diet body can t synthesize indispensible and conditionally essential amino acids are when a nonessential amino acid becomes essential How to form and make proteins One amino acid loses a hydrogen and an oxygen the other loses a hydrogen from the amino group Diapeptides 2 amino acids Tripeptides 3 amino acids polypeptides 10 or more amino acids levels of structure primary structure determined by amino acid sequence secondary structure determined by polypeptide shape and weak electrical attractions chain can twist into helix or fold into pleated sheet tertiary structure twists into a variety of complex shapes polypeptide tangles may have hydrophilic phobic side groups may carry electrical charge coiled and twisted chains give stability quaternary structure involves interactions between 2 or more polypeptides most complex structure possible peptide bond bond that links one amino acid to another process of protein synthesis in cell 1 DNA serves as a template to make strands of mRNA and each mRNA copies exact instructions 2 mRNA leaves nucleus through nuclear membrane mRNA attaches itself to the protein making machinery of the cell the ribosomes 4 tRNA collects amino acids from the cell fluid Each tRNA carries its amino acids to mRNA which dictates sequence in which amino acids attached to form protein strands Denaturation irreversible damage to structure of protein uncoiling results in loss of function may destroy body proteins breakdown of proteins in stomach Where digestion starts the mouth enzymes involved HCL uncoils protein strands and activates stomach enzymes Pepsin breaks proteins in stomach into smaller peptides Pancreatic and Intestinal processes and Intestinal tripepidases and dipepidases how amino acids are absorbed protein carriers
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