Anish Kaushal Biology Exam Study Sheet January 21 12 Biological Macromolecules Functional Groups Macromolecules are large molecules that usually consist of smaller subunits They are organic molecules because they contain carbon atoms The bonding ability of carbon and the variety of ways carbon atoms can be arranged results in many possible organic compounds Macromolecules often contain regions of carbon and hydrogen atoms hydrocarbon chains as the backbone or skeleton of a molecule Hydrocarbons alone are non polar and non reactive since molecules tend to be symmetrical and C H bonds are non polar Functional groups usually consist of a polar group of atoms usually O N P and or S are involved Functional groups Groups are hydroxyl OH carbonyl CO or COH carboxyl COOH amino NH2 sulfhydryl SH and Phosphate PO4 3 Addition of functional groups enables macromolecules to o Become more soluble in water OH o React with other compounds all o Regulate pH amino carbonyl o Change shape structure SH o Store and release energy PO4 3 Types of macromolecules Contain carbon Hydrogen and oxygen 1 Carbohydrates Always in 1C 2H 10 ratio 1 carbon per 1 H2O molecule Reserve starch in plants glycogen in animals Provide short and medium term energy for organisms Immediate use simple sugars glucose Can also be used to build structures ex plant cell walls are made of cellulose a carb and insect shells are made of chitin another type of carb Types of Carbs a Monosaccharide Can have 3 or more carbons When dry they are linear molecules with a carbonyl aldehyde COH or ketone CO and several hydroxyls When in solution those with 5 or more carbons will become cyclic ring shaped molecules the carbonyl bonds with the 2nd to last carbon b Disaccharide 2 monosaccharides bonded together Ex sucrose glucose fructose lactose glucose galactose etc They can be linked together by any of the exposed hydroxyl groups c Oligosaccharide d Polysaccharides Short chains of 3 10ish monosaccharides Huge number of combinations Often attached to cell surfaces for signaling and establishing cell identity Long chains up to 100 s of monosaccharides Called complex carbs Ex starch single chain glycogen bonded chains cellulose cross linked fibres made of bundled chains chitin 2 Lipids fats oils Anish Kaushal Biology Exam Study Sheet January 21 12 Contain C O H but not in same ratio as carbs Non polar therefore not soluble in water Uses o Major component of all cell membranes phospholipid o Long term energy storage excess carbs fats o Insulation o Cushions internal organs o Make steroid hormones chemical messages Types of Fats a Triglycerides Contain 3 fatty acids 1 glycerol molecule Each carbon of the fatty acid can either be saturated all bonded to H atoms or unsaturated double bonded C atoms with H atoms giving them either a straight or kinked shape Saturated fats tend to be tightly packed because they are straight solid at room temperature example butter Unsaturated fats tend to be loosely packed o Tend to be liquid at room temperature ex vegetable oil o Better for body because loosely packed and saturated tends to stack and accumulate o Different types of unsaturated fats Trans fats and Cis fats o Trans fats unsaturated fat whose molecules contain a trans double bond between carbon molecules due to the process of partial hydrogenation carbon is on opposite side of each other o Trans fats tend to clump together in your arteries because they re straight causing plaque build up which can lead to heart disease and an increase in your chance of getting a heart attack o Trans fats are flat straight whereas most unsaturated fats like cis fats are naturally kinked o Cis fats trans fats with H bonded on the same side b Phospholipids Similar to triglycerides but one fatty acid chain is replaced by a phosphate group PO4 Phosphate is polar and negatively charged whereas the 2 fatty acid chains are non polar In p lipids a polar R group is attached to the phosphate resulting in a polar head on the molecule 2 hydrophobic non polar tails hydrophilic head polar P lipids can have a fatty acid tail that is monosaturated helps maintain membrane s fluid nature Other lipids include fatty acids and sterols like cholesterol 3 Proteins Made of long polymers 50 amino acids 20 different kinds of amino acid subunits They all contain common C H O N structure but they all differ in their R groups residual groups 12 amino acids can be made by our body and the other 8 are called the essential amino acids because they come from our food Anish Kaushal Biology Exam Study Sheet January 21 12 When amino acid polymers are folded into a 3D shape that is unique to each sequence of amino acid they are called proteins However before the folding they are called polypeptide chains chain of amino acids 3D shape is caused by bonding between the R groups of different amino acids in the chain tertiary folding The shape determines its function Proteins have greatest diversity in function o Major structural components of all cells tissues microtubules in cell o Act as enzymes for all biochemical reactions o Make protein hormones ex insulin o Form channels that help transport molecules across cell membranes o Form antibodies of immune system that recognize microbes disease act as marks recognize particles that are foreign for antigens Different types of protein structure o Primary protein structure sequence of amino acids o Secondary protein structure occurs when the sequence of amino acids are linked through hydrogen bonds H on amino group and O on carboxyl group create a helix and Beta sheets o Tertiary protein structure certain attractions between alpha helix and pleated sheets bonding interactions between R groups on different amino acids o Quaternary protein structure protein consisting of more than one amino acid chain 4 Nucleic Acids Form different types of coded instructions for the cell Code can be DNA deoxyribonucleic acid or RNA ribonucleic acid o DNA is the code for making RNA o RNA is the code for making proteins o DNA RNA proteins Nucleic acids are made of long polymers of different types of nucleotide subunits 3 components of a nucleotide a One sugar molecule ribose deoxyribose 5 sided ring b One phosphate group the acid c 1 nitrogenous base code adenine guanine thymine cytosine uracil T C U have 1 six sided ring while A G have 1 six sided ring bonded to a 5 sided ring DNA has of 2 complementary strands of nucleotides arranged in a double helix twisted ladder A T G C RNA is
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