Nucleotide and Nucleic Acid Structure Lecture Note

University:
Boston University
Course:
CAS BI 108 | Biology 2
Academic year:

2023
Views:

247

Pages:

19
Author:

Nayeli Barrera

Nucleotide and Nucleic Acid Structure Introduction to Cells & Microscopy • Outline of today’s supplemental lecture • Nucleotide and nucleic acid structure • Central Dogma • Replication • Transcription • Translation • Quiz at the end of the lecture Structural Components of Nucleotides Glycosidic bond Nucleic acid – polymer of nucleotides – directionality 5’3’ When you write a sequence: ATCG Phosphodiester bond It is assumed that the 5’-end is on the left and the 3’-end is on the right, unless otherwise labeled. 5’-ATCG-3’ Chargaff’s Rules B-Form DNA Figure 3-8 Computer-simulated space-filling model of DNA. Video: Computer-simulated space-filling model of DNA. SUMMARY (34 Å) sugar–phosphate backbone (phosphodiester bonds) Right-handed, antiparallel, doublestranded helix. With the “base complementarity,” it explains genetic material: • Storage of genetic information • Replication • Information retrival Central Dogma of Molecular Biology Introduction to Cells & Microscopy From DNA to Protein: Gene Expression • Central Dogma: from Genes to Proteins • Replication of the genes (DNADNA) • Transcribing the information (DNARNA) • Translating the nucleotide sequence into protein sequence (RNAProtein) – The Genetic Code – Protein Biosynthesis Central Dogma The central dogma of molecular biology Replication Information Flow Replication DNA replication is semiconservative (Meselson-Stahl Expt) DNA Replication Arthur Kornberg showed that DNA contains information for its own replication. He combined in a test tube: DNA, the four deoxyribonucleoside triphosphates (dNTPs–monomers), DNA polymerase, salts (Mg+2), and buffer. The DNA served as a template for synthesis of new DNA. Each New DNA Strand Grows from Its 5´ End to Its 3´ End Each New DNA Strand Grows from Its 5´ End to Its 3´ End ALL polymerases add nucleotides to the 3’ end (Direction is termed 5’  3’) Pyrophosphatase