Lesson Outcome: Nucleic Acid Structure and OmpathStudy

By the end of this lesson, you should be able to: 1. Understand and Illustrate the Primary Structure of Nucleic Acids Identify and describe the key components of nucleic acids: Phosphate group (P) Nitrogenous bases (N) (Purines: adenine, guanine; Pyrimidines: cytosine, thymine/uracil). Pentose sugars (Deoxyribose in DNA; Ribose in RNA). Draw and label :A nucleotide showing sugar, nitrogenous base, and phosphate groups. Deoxynucleotide triphosphates (dNTPs) with all three phosphate groups. RNA nucleotide (rNTP) and compare it with DNA nucleotides. ATP structure, explaining its role in energy transfer. Explain how nucleotides are linked by phosphodiester bonds to form the sugar-phosphate backbone. 2. Describe and Illustrate the Secondary Structure Understand and describe the bonds stabilizing the structure: Hydrogen bonds between complementary bases. Base pairing rules: A-T (or A-U in RNA) and G-C. Discuss structural differences between RNA and DNA: RNA : Single-stranded, forms loops and folds (e.g., hairpins). DNA : Double-stranded helix with antiparallel strands (5’ to 3’ direction). Draw and label :Single-stranded RNA showing phosphodiester bonds and base pairs. DNA’s double helix :Include 5’ and 3’ ends. Show base pairing and antiparallel strand orientation. 3. Explain the Tertiary Structure of DNA Describe how DNA forms complex 3D shapes: A-DNA : Found under dehydrated conditions; right-handed helix. B-DNA : Most common in cells; right-handed helix with ~10.5 base pairs per turn. Z-DNA : Rare, left-handed helix; forms under high salt conditions or during transcription. Compare shapes, nucleotide arrangement, and functional significance. Draw and label :Simple representations of A-DNA, B-DNA, and Z-DNA. 4. Discuss the Quaternary Structure Understand how DNA interacts with proteins to form higher-order structures:Role of histones in forming nucleosomes and chromatin. Interaction of DNA with other proteins via ionic and hydrogen bonds. Explain how DNA compacts into chromosomes. 5. Explore the Chemical Properties of DNA Discuss DNA’s chemical stability due to:Hydrogen bonding between bases. Hydrophobic interactions within the double helix. Explain denaturation and renaturation of DNA. 6. Explain DNA Replication Understand the process of DNA replication:Semiconservative nature of replication. Directionality of replication (5’ to 3’). Role of enzymes such as helicase, DNA polymerase, and ligase. Illustrate :Replication fork showing leading and lagging strands. Practical and Drawing Skills Draw and label :Nucleotides, ATP, dNTPs, and RNA nucleotides. DNA and RNA structures, including phosphodiester bonds. Double helix with antiparallel strands and base pairing. Illustrate :DNA tertiary structures (A, B, and Z forms). DNA-protein interaction in quaternary structure. Key steps in DNA replication. ---