BIOL 1441 1st Edition Lecture 7 Outline of Last Lecture I 4 main classes of molecules II Macromolecules III Carbohydrates a Monosaccharides b Disaccharides Outline of Current Lecture I Polysaccharides II Lipids a Fats b Phospholipids c Steroids III Proteins Current Lecture I Polysaccharides macromolecules a Polymers of monosaccharides monomers i Hundreds thousands monomers ii Storage roles energy storage quick energy iii Structural roles 1 Bonds between monomers determine whether storage or structural b The structure and function of a polysaccharide are determined by i Sugar monomers ii Positions of glycosidic linkages These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II c Storage Polysaccharides i Starch storage polysaccharide of plants 1 Consists entirely of glucose monomers 2 Granules within chloroplasts other plastids 3 Stored glucose major cellular fuel energy 4 Hydrolyze starch potatoes wheat corn 5 1 4 linkage helical shape ii Glycogen storage polysaccharide in animals 1 Mainly in liver muscle cells 2 Hydrolyze glycogen sugar demand increases a Cannot sustain you for long 1 day replenish with food iii Cellulose major structural component of plant cell walls 1 Abundant organic compound on earth 2 Polymer of glucose different glycosidic linkages 3 Difference based on 2 ring structures of glucose alpha a beta b iv Structural Polysaccharides plants 1 Starch a glucose helical shape 2 Cellulose b glucose straight a H on one strand H bond with OH on other strands b Parallel cellulose molecules grouped into microfibrils form strong building materials for plants 3 Enzymes digest starch by hydrolyzing a linkages can t hydrolyze blinkages in cellulose 4 Cellulose passes through the digestive tract as insoluble fiber a Abrade the wall stimulating mucus secretion b Aids in the smooth passage of waste 5 Some microbes possess enzymes digest cellulose a Cows harbor bacteria rumen hydrolyze hay grass b Termites microbes to digest wood c Symbiotic relationships v Structural Polysaccharides animals 1 Chitin exoskeleton of arthropods cell walls of many fungi 2 Chitin can be used as surgical thread Lipids do not form polymers i Hydrophobic no affinity for water ii Consist mostly of hydrocarbons iii Nonpolar covalent bonds iv Some polar regions v Most biologically important lipids 1 Fats 2 Phospholipids 3 Steroids b Fats i Not polymers but are large molecules 1 Assembled from smaller molecules 2 Dehydration reactions ii Constructed from 2 types of smaller molecules 1 Glycerol hydroxyl group 2 Fatty acids iii 3 fatty acids join to glycerol by an ester linkage creating a triacylglycerol triglyceride 1 Ester linkage bond between hydroxyl group carboxyl group 2 Triglyceride 3 fatty acids 3 Fat molecule glycerol 3 fatty acids iv Fatty Acids 1 Vary in length number of carbons number and locations of double bonds 2 Saturated fatty acids maximum number of hydrogen atoms possible no double bonds 3 Unsaturated fatty acids 1 or more double bonds 4 Major function of fats energy storage 5 Look in hydrocarbon tail for double bonds v Saturated Fats 1 Fats made from saturated fatty acids 2 Most animal fats are saturated 3 Solid at room temperature 4 Cardiovascular disease plaque deposits vi Unsaturated Fats 1 Fats made from unsaturated fatty 2 Plant fish fats usually unsaturated 3 Healthy fats 4 Liquid at room temperature oils a Cant be solids b c double bonds 5 Double bonds removal of hydrogen atom 6 Cis double bond kink a Most common 7 Partially Hydrogenated 8 Take unsaturated fat and remove double bonds 9 Add hydrogens hydrogenate a Peanut butter margarine prevents lipids from separating out vii Trans fats 1 Greater health concern than natural saturated fats 2 Not found in nature so body doesn t recognize it 3 Trans bond body enzymes lipase don t recognize III viii Fats Function Energy Storage 1 Gram of fat twice as much energy as a gram of sugar polysaccharide way more hydrogen a Plants immobile bulky storage starch granules b Animals carry their energy stores around compact c Long term storage adipose cells d Protect vital organs e Insulation marine mammals c Phospholipids i 2 fatty acids phosphate group attached to glycerol ii Fatty acid tails hydrophobic iii Phosphate group attachments form a hydrophilic head polar iv Added to water self assemble into bilayer 1 Hydrophobic tails pointing toward the interior 2 Polar heads exterior 3 Cell membranes d Steroids completely non polar i Four fused rings of carbon ii Carbon skeleton consisting of four fused rings 1 Vary in their functional groups iii Cholesterol an important steroid is a component in animal cell membranes 1 Precursor to hormones testosterone estrogen Proteins a Monomer amino acid b Polymer polypeptides chains of amino acids i Linked by peptide bonds ii Peptide 8 12 amino acids c Polypeptide protein d Protein are complex i Consist of one or more polypeptides e Enzymes i Protein catalyst speeds up chemical reactions without being consumed ii Perform their functions repeatedly iii ase enzyme f 20 Amino Acids i Organic molecule with carboxyl amino groups ii Amino acids differ in their properties due to differing side chains R groups iii Amino acids are classified according to their SIDE GROUPS ONLY iv All amino acids have backbone 1 One amino group 2 One asymmetric carbon 3 One carboxyl group 4 One hydrogen