Monomers, polymers, and macromolecules There are 4 categories of macromolecules: Carbohydrates Proteins, Lipids, and Nucleic acids

Biomolecules The Raw Materials of Biotechnology The Molecules of Cells

 Organic chemistry  Chemistry of Carbon  CHNOPS ◦ Carbon ◦ Hydrogen ◦ Nitrogen ◦ Oxygen ◦ Phosphorus ◦ Sulfur ◦ Several Trace Minerals Elements of Life

Most are polymers All are organic (C) compounds Carbohydrates Proteins Lipids Nucleic Acids Differ in terms of composition and function Four Main Types of Biomolecules

Carbon is the central element All biomolecules contain a Carbon chain or ring Carbon has 4 outer shell electrons (valence = 4) Therefore it ’ s bonding capacity is great It forms covalent bonds –hence, has strong bonds Once bound to other elements (or to other Carbons), it is very stable

Carbon linkages Single chains Rings Propane The 4 types of biomolecules often consist of large carbon chains = C 3 H 8 CH 4 =

Carbon binds to more than just hydrogen!! To OH groups in sugars To NH 2 groups in amino acids To H 2 PO 4 groups of nucleotides of DNA, RNA, and ATP Amino acid OH, NH2, PO4 are called ‘ functional groups ’ !

Fig. 3.1 Functional groups:

Isomers have the same molecular formulas but different structures Structural isomerStructural isomer = difference in the C skeleton structure StereoisomerStereoisomer = difference in location of functional groups

Enantiomers Enantiomers are special types of stereoisomers Enantiomers are mirror images of each other chiral One such enantiomer contains C bound to 4 different molecules and is called a chiral molecule D formL form Chiral molecules rotate polarized light to the right (D form) or to the left (L form) molecules Examples: amino acids (L form) sugars (D form)

Monomers and polymers Monomers are made into polymers via dehydration reactions Polymers are broken down into monomers via hydrolysis reactions

Fig. 3.3

Carbohydrates (or sugars) Simple sugars (monosaccharides) Only one 3-C, 5-C, 6- C chain or ring involved

Fig. 3.5 Examples of sugar monomers* *Remember how C ’ s are counted within the ring structures (starting from the right side and counting clockwise)

Carbohydrates (sugars) Double sugars (disaccharides) Two 6-C chains or rings bonded together

Carbohydrates (sugars) Complex carbo ’ s (polysaccharides) –Starch –Cellulose –Glycogen –Chitin Glycogen to glucose in animals

Fig. 3.9 Polysaccharides Starch structure vs Glycogen structure

Fig Polysaccharides: Cellulose structure

Proteins Composed of chains of amino acids 20 amino acids exist Amino acids contain –Central Carbon –Amine group –Carboxyl group –R group

Fig The 20 Amino Acids All differ with respect to their R group

Peptide bonds Peptide bonds occur between amino acids The COOH group of 1 amino acid binds to the NH2 group of another amino acid peptide bondForms a peptide bond!

Fig The chain (polymer) of amino acids forms a variety of loops, coils, and folded sheets from an assortment of bonds and attractions between amino acids within the chain(s)

There are at least 7 functions of proteins Enzyme catalysts – specific for 1 reaction Defense – antibody proteins, other proteins Transport- Hgb, Mgb, transferrins, etc Support – keratin, fibrin, collagen Motion – actin/myosin, cytoskeletal fibers Regulation- some hormones, regulatory proteins on DNA, cell receptors Storage – Ca and Fe attached to storage proteins

Fig. 3.18

There are four levels of protein structure Primary = sequence of aa ’ s Secondary = forms pleated sheet, helix, or coil Tertiary = entire length of aa ’ s folded into a shape Quaternary = several aa sequences linked together

Fig Motifs and Domains: Important features of 2° and 4° structure

Nucleic acids: DNA and RNA DNA = deoxyribonucleic acid DNA is a double polymer (chain) Each chain is made of nucleotides The 2 chains bond together to form a helix

nucleotides DNA nucleotides Each nucleotide in DNA contains: –5-C sugar (deoxyribose) –Phosphate –Nitrogen base -adenine (A) -guanine (G) -cytosine (C) -thymine (T)

Fig One polymer of nucleotides on one “ backbone ” of nucleic acid

Fig The DNA “ double helix ”

Lipids: Hydrophobic molecules Central core of glycerol Bound to up to 3 fatty acid chains They exhibit a high number of C-H bonds – therefore much energy and non-polar When placed in water, lipids spontaneously cluster together They help organize the interior content of cells  “ phospholipids ”

Glycerol and fatty acid chains What specific bonds form between glycerol and each fatty acid chain? Would you think this to be an hydrolysis or a dehydration synthesis rxn?

Saturated and unsaturated fats The difference resides in the number of H ’ s attached to C ’ s in the fatty acid chains; the amount of “ saturation ” on the C ’ s

Saturated vs unsaturated fats and diet Saturated fatsSaturated fats raise LDL-cholesterol levels in the blood (animal fats, dairy, coconut oil, cocoa butter) Polyunsaturated fatsPolyunsaturated fats leave LDL-cholesterol unchanged; but lower HDL-cholesterol (safflower and corn oil) Monounsaturated fatsMonounsaturated fats leave LDL and HDL levels unchanged (olive oil, canola, peanut oil, avocados) Omega-3 fatty acidsOne variety of polyunsaturated fat (Omega-3 fatty acids) guards against blood clot formation and reduce fat levels in the blood (certain fish, walnuts, almonds, and tofu)

Phospholipids and cell membranes P-lipids make up the majority of cell membranes including: –The plasma membrane –Nuclear envelope –Endoplasmic reticulum (ER) –Golgi apparatus –Membrane-bound vesicles

Structure of single P-lipid The 3 C ’ s of glycerol are bound to: 2 fatty acid chains phosphate

Cell environment organizes P-lipid bilayer to proper orientation Hydrophilic (polar) “ heads ” of P-lipid oriented to the exterior; hydrophobic (non-polar) “ tails ” oriented to the interior