Macromolecules Building Complex Molecules That Comprise Living Things Organic Macromolecules Contain Carbon Question: How many electrons does carbon need to fill its outer energy level? Answer: Four Therefore, each carbon atom can four covalent bonds with make ____ other types of atoms or additional carbons. In a triple bond, carbons share three pairs of electrons In a double bond, carbons share two pairs of electrons Carbon Atoms Bind to Functional Groups Organic Molecules Can Exist as Isomers Structural Isomers have the same atoms in different bonding relationships Stereoisomers have different spatial positioning for the same bonding relationships Macromolecules: Polymers Made of Repeating Monomers Macromolecule Carbohydrates Lipids Proteins Monomer Unit Nucleic Acids Nucleotides Sugars Fatty acids Amino acids Synthesis and Breakdown of Macromolecules Condensation or Dehydration Synthesis Hydrolysis Removal of water to add monomer units Addition of OH and H groups of water to break a bond between monomers Dehydration Synthesis / Hydrolysis Dehydration Synthesis Hydrolysis Nucleic Acid Structure and Function Information Flow From DNA replication (prior to cell division) Gene: sequence of DNA that codes for a protein DNA transcription RNA translation Protein (ongoing cellular metabolism) DNA and RNA Structure DNA RNA Primary Structure Chain of nucleotides Chain of nucleotides Secondary Structure Double helix Single folded chain Three Parts of Nucleotide Structure NH2 Phosphate Group OH HO P O HC O N C C N CH C N CH2 O N Deoxyribose Nitrogenous H or H Base (1 of 5) Ribose H H OH H 5-Carbon Sugar DNA and RNA Structure DNA Purine bases Pyrimidine bases 5-carbon sugar Adenine (A) Guanine (G) Adenine (A) Guanine (G) Cytosine (C) Thymine (T) Cytosine (C) Uracil (U) deoxyribose OH Phosphate RNA PO4 H ribose OH OH PO4 Nucleotide Chain Nucleotides are joined together by dehydration synthesis The phosphate of one nucleotide is joined to sugar of next nucleotide, forming a “sugar-phosphate backbone” 3’ end A C G pairs with C T A A T G C A T 3’ end has free sugar G 5’ end has free phosphate •Two nucleotide chains •In opposite orientations •Held together by hydrogen bonds •Twisted into a helix T DNA Structure A pairs with T 5’ end T C A G DNA Secondary Structure The Double Helix • Two polynucleotide chains are wound together • Bases are located inside the helix • Sugar-phosphate groups are on the outside as a “backbone” • Bases are arranged like rungs on a ladder, perpendicular to the “backbone” • 10 base pairs per turn of the helix DNA Replication •DNA chains separate •Each chain is used as a pattern to produce a new chain •Each new DNA helix contains one “old” and one “new” chain Transcription = Production of RNA Using DNA as a Template •DNA chains separate •ONE DNA chain is used as a pattern to produce an RNA chain •RNA chain is released and the DNA chains reform the double-helix In DNA In RNA A U T A G C C G RNA Secondary Structure Single, Folded Chain • Each RNA has a unique structure based on its nucleotide sequence • RNA-RNA Base Pairing Rules – A pairs with U – G pairs with C • Can link – bases in proximity – distant base sequences Functions of Nucleotides and Nucleic Acids DNA RNA Hereditary Material, specifies protein sequences Intermediate in protein production Ribozymes RNA catalysts ATP GTP cAMP (cyclic AMP) Energy transfer Energy transfer Activator/Inhibitor in Signal Transduction Secondary messenger in Signal Transduction