Macromolecules-Lecture (1).pdf

MACROMOLECULES  ORGANIC COMPOUNDS §Compounds that contain CARBON are called organic. §Macromolecules are large organic molecules. CARBON (C) § Carbon has 4 electrons in outer shell. § Carbon can form covalent bonds with as many as 4 other atoms (elements). § Usually with C, H, O or N. § Exa...

MACROMOLECULES  ORGANIC COMPOUNDS §Compounds that contain CARBON are called organic. §Macromolecules are large organic molecules. CARBON (C) § Carbon has 4 electrons in outer shell. § Carbon can form covalent bonds with as many as 4 other atoms (elements). § Usually with C, H, O or N. § Example: CH4(methane)  CH4 = CARBON LINKAGES Propane § Single chains § Rings = C3H8 The 4 types of biomolecules often consist of large carbon chains  MACROMOLECULES § Large organic molecules § POLYMERS – long molecules consisting of many similar or identical building blocks linked by covalent bonds § MONOMERS – repeating units that serve as building blocks of a polymer §Names of the 4 macromolecules §Structure - monomers and polymers of each §Function - what are they used for? §Food sources - what foods will you find these in? MONOMERS AND POLYMERS § Monomers are made into polymers via dehydration reaction or condensation polymerization § Polymers are broken down into monomers via hydrolysis reaction MACROMOLECULES 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids (DNA and RNA) Fig. 3.3 CARBOHYDRATES  CARBOHYDRATES §Monomer / Building block: MONOSACCHARIDE A. monosaccharide B. disaccharide C. polysaccharide  Carbohydrates sugars Monosaccharides Disaccharides Polysaccharides (monomers) ( Dimers) (polymers) Biological molecules 14 Examples of sugar monomers  § Fructose – fruit sugar § Galactose – milk sugar § Glucose – blood sugar Biological molecules 17  § Lactose (milk sugar): glucose + galactose § Maltose (malt sugar): glucose + glucose § Sucrose (table sugar): glucose + fructose sucrose Biological molecules Biological molecules POLYSACCHARIDES § Complex carbohydrates (polysaccharides) § Starch § Glycogen § Cellulose § Chitin Glycogen to glucose in animals Polysaccharides: Cellulose structure Chitin – arthropod exoskeleton and fungal cell wall §modified form of cellulose Biological molecules 26 PROTEINS  PROTEINS §Monomer: Amino Acid §Amino acids (20 different kinds of aa) bonded together by peptide bonds (polypeptides). Fig. 3.18  20 naturally occurring and encoded by DNA Asdf Asdf Biological molecules 33 Biological molecules 36 Biological molecules 37 Biological molecules 38 Biological molecules 39 Biological molecules 40 Biological molecules 41 Biological molecules 42 Biological molecules 43 Biological molecules 44  DNA §Amino acids are JOIN together by Transcription §PEPTIDE BONDS mRNA §Following a Translation sequence dictated Polypeptide/ by the DNA Protein Biological molecules n Shape of a proteins are important because n This determines how they interact with other molecules n This determines their particular function Biological molecules 47 § Proteinshave complex structures. The shape of a protein determines its function! § The levelsof protein structure are: § Primary structure: polypeptide chain § Secondary structure: polypeptides in coils or sheets § Tertiary structure: coils or sheets form a tangle § Quaternary structure: more than one tangle combine to make a very complex protein! Amino acid chain Regions stabilized by hydrogen bonds between atoms of the polypeptide backbone 3D shape stabilized by interactions between side chains Association of two or more polypeptides (some proteins only) LIPIDS  LIPIDS § Compounds which are not soluble in water. § “stores the most energy” Functions of lipids: 1. Long term energy storage 2. Protection against heat loss (insulation) 3. Protection against physical shock 4. Protection against water loss 5. Chemical messengers (hormones) 6. Major component of membranes (phospholipids) §Most lipids are composed of a of glycerol molecule with attached fatty acids GLYCEROL FATTY ACIDS Glycerol Fatty acid Fatty acid Triglyceride Fatty acid Phospholipid GLYCEROL HYDROPHOBIC END Glycerol Fatty acid Fatty acid PO4 FATTY ACIDS Biological molecules 61 HYDROPHYLIC END GLYCEROL AND FATTY ACID CHAINS § Some lipids have a four ringed structure § Eg. Cholesterol and other lipids that are derived from cholesterol Biological molecules 63 LIPIDS 1. Fats 2. Phospholipids 3. Oils 4. Waxes 5. Steroid hormones  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 STRUCTURE OF PHOSPHOLIPID The 3 C’s of glycerol are bound to: 2 fatty acid chains phosphate CELL ENVIRONMENT ORGANIZES PHOSPHOLIPID BILAYER TO PROPER ORIENTATION Hydrophilic (polar) “heads” of P-lipid oriented to the exterior; hydrophobic (non-polar) “tails” oriented to the interior § An important structural component of membranes Phospholipids are the primary structural component of all cellular membranes, such as the plasma membrane (false color TEM above). Biological molecules 74 § acts as a shock absorber and good insulator The white fat tissue (arrows) is visible in this ox kidney Fat absorbs shocks. Organs that are prone to bumps and shocks (e.g. Stored lipids provide insulation kidneys) are cushioned with in extreme environments. a relatively thick layer of fat. Increased body fat levels in winter reduce heat losses to the Biological molecules environment. 75 § Water proofing of some surfaces § Transmission of chemical messages via hormones Waxes and oils, when secreted on to surfaces provide waterproofing in Biological molecules plants and animals. 76 NUCLEIC ACIDS  NUCLEIC ACIDS §Monomer: Nucleotides §Two types: a. Deoxyribonucleic acid (DNA- double helix) b. Ribonucleic acid (RNA-single strand) NUCLEIC ACIDS Nucleotides include: §phosphate group §pentose sugar (5-carbon) §nitrogenous bases: adenine (A) thymine (T) DNA only uracil (U) RNA only cytosine (C) guanine (G) NUCLEOTIDE Phosphate Group O 5 O=P-O CH2 O O N Nitrogenous base C4 C1 (A, G, C, or T) Sugar (deoxyribose) C3 C2 DNA - DOUBLE HELIX 5 O 3 3 O P 5 P 5 O 1 G C 3 2 4 4 2 1 3 5 O P P 5 T A 3 O O 5 P 3 P One polymer of nucleotides on one “backbone” of nucleic acid purines pyrimidines Biological molecules 84 Biological molecules 86 Macromo Broken down in Enzymes lecule stomach to: eaten: Carbohyd Simple sugars (i.e. rates glucose) Lipids Fatty acids & glycerol (glycerol further broken down to glucose) Proteins Amino acids Nucleic Nucleotides Acids