1. Molecular BiochemistryBioc.432 Lab 1: Introduction to nucleic acids (Structural properties)

3. Nucleotide Structure Nucleic acids are polymers of nucleotides Nucleotides consist of –sugar RNA - ribose DNA - deoxyribose –phosphate group –nitrogenous base

4. Nitrogenous Bases Purines - double carbon-nitrogen (bicyclic rings) Pyrimidines - single carbon-nitrogen ring (monocyclic rings) –uracil - RNA only –thymine - DNA only

5. Complementary Base Pairing Nitrogenous bases form hydrogen bonds Base pairs –A-T and C-G Law of complementary base pairing –one strand determines base sequence of the other Sugar-phosphate backbone Segment of DNA

6. DNA Structure : Twisted Ladder

7. DNA Function DNA is located in nucleus but small amount in the mitochndria. Serves as code for protein synthesis, cell replication and reproduction Gene - sequence of DNA nucleotides that codes for one polypeptide Genome - all the genes of one person

8. RNA Structure and Function Only one nucleotide chain RNA forms globular conformations, in which regions of helical structure are formed by intramolecular hydrogen bonds (secondary structure)

9. RNA RNA much smaller than DNA  transfer RNA (tRNA) has 70 - 90 bases  messenger RNA (mRNA) has over 10,000 bases  DNA has over a billion base pairs Ribose replaces deoxyribose as the sugar Uracil replaces thymine as a nitrogenous base Essential function: 1.Interpret DNA code 2.Direct protein synthesis

10. Types of RNA Messenger RNA – mRNA - re-writes DNA (transcription) and takes it out of the nucleus to the ribosome. Transfer RNA – tRNA -Carries amino acids in the cytoplasm to the ribosomes. Ribosomal RNA - rRNA- Building blocks of ribosomes. Assembled in the nucleolus. Small nuclear RNA- snRNA- small RNA molecules found in the nucleus. Important in number of processes including the maintenance of telomeres.