Structure and Function of Macromolecules IB Biology Organic Chemistry Structure and Function of Macromolecules IB Biology

Vocabulary Check SIZE prefixes Mono Poly Di Miscellaneous One Poly Many Di Two Miscellaneous Lysis = to break BIOMOLECULE roots Sacchar- Sugar End in -ose Peptide Protein Enzymes: end in -ase Lipid Fat

The synthesis and breakdown of polymers

Dehydration Synthesis & Hydrolysis Building bigger molecules Dehydration synthesis Removing water to create a bigger molecule Breaking up big molecules Hydrolysis Uses water to break apart a big molecule into subunits

Building and Breaking Molecules Dehydration Synthesis vs. Hydrolysis OH H OH OH OH + + H H H 2H2O Hydrolysis 2H2O Dehydration Synthesis OH OH OH + + H H H OH H Explanation: A starch molecule (polymer) becomes the glucose (monomers) that make it up. Explanation: 3 Glucose molecules (monomers) bind to create a Starch molecule (polymer).

What does this look like in sugars? Dehydration Synthesis Reaction Carbons are numbered (for ease) Links can be made between different carbons Glycosidic linkage is a covalent bond between 2 monosaccharides

Carbohydrates Energy Source Carbon Source Cell processes require energy Mono/disaccharides Polysaccharides – stored energy (starch for plants, glycogen for animals) Carbon Source Structure; building material (cellulose for plants) Can be used to construct amino acids and fatty acids

Monosaccharide Characteristics Ring structure Formula = C6H12O6 Generally sweet Examples: glucose, fructose, galactose, ribose, deoxyribose Function = Source of quick energy or raw material for creating other molecules

Disaccharide Characteristics 2 ring structure with a glycosidic linkage Formula = C12H22O11 Generally semi-sweet Examples: sucrose, maltose, lactose Function = Source of fairly quick energy or raw material for creating other molecules

Polysaccharides: Starch vs. Cellulose Both are chains of glucose Cellulose does not dissolve in water (cotton does not dissolve when you wash it) You use starch as an energy source via respiration You do not have the enzyme to digest cellulose

What are Lipids? Hydrophobic molecules (have a “fear” of water) Most diverse biomolecule category. Examples: Fats Phospholipids Steroids Waxes & Pigments

Lipids Fats (triglycerols) Energy storage in animals. Fat cells are designed for continuous synthesis and breakdown of triglycerols, controlled mainly by the activation of hormone-sensitive enzyme lipase. Provides high caloric content, about 9 kcal/g, compared with 4 kcal/g for the breakdown of carbohydrates and proteins. Migratory birds that must fly long distances without eating use stored energy of triglycerols to fuel their flights.

Saturated vs. Unsaturated As many hydrogen as possible are bonded to the carbon chain. Solid at room temp. Unsaturated One or more double bonds forms a kink. Liquid at room temp.

Saturated vs. Unsaturated Fats All single bonds Straight shape, compact Solid at room temp. Ex. Butter, lard UNSATURATED Include 1+ double bond Kinked shape, not compact Liquid at room temp. Ex. Vegetable oil

Phospholipids (cell membranes) Carbon chain is non-polar (doesn’t dissolve in water) Phosphate is polar (dissolves in water)

Phospholipids Major part of cell membranes Structure: 2 Hydrophobic tails Hydrophilic head In a bilayer

Steroids Carbon rings are non-polar Non-polar means hydrophobic

Steroids Regulate organism functioning Structure: 4 fused rings with different side groups Note: change in side groups = change in function

What’s Up with Proteins? Amino Acid/peptide = the monomer of proteins Amino acids join by peptide bonds into a polypeptide A protein is more than just a chain of polypeptides Shape is essential!! COMPONENTS: Amine group (NH2) Carboxyl group (COOH) R group (different for each of 20 amino acids)

Protein (amino acid + amino acid + amino acid, etc.)

Are proteins diverse? A 20 letter “alphabet” Proteins can be 100s or 1000s of “letters” long Imagine the diversity!

Protein Functions Structure – support (connective tissue, webs) Storage – store amino acids; egg white, milk, seeds Transport – hemoglobin (carries oxygen), channels (H+ through ATP synthase) Hormonal – regulation; insulin Receptor – Na+ and K+ receptors in nervous system Contractile – movement (actin/myosin in muscle) Defense – antibodies fight bacteria/viruses Enzymes – speed up chemical reactions

4 levels of Protein Structure Primary Unique sequence of amino acids Secondary Hydrogen bonds create coils and folds Alpha helix Beta pleated sheets Tertiary Irregular contortions do to side chain (disulfide bridges) Quaternary Two or more polypeptides joined together

Levels of Protein Structure Primary (1°)—amino acid sequence Secondary (2°)—folds/coils of amino acid change caused by hydrogen bonds Tertiary (3°)—interactions between R groups Quaternary (4°)—2+ polypeptides that form one functional protein

Primary Structure

Secondary Structure

Tertiary Structure

Quaternary Structure

What are Nucleic Acids? Information Storage Molecules Consist of other molecules Deoxyribose or Ribose sugars Phosphate groups (also in some lipids) Nitrogenous bases Store the blueprints that make the proteins that create your traits!