1 / 17

8. Nucleotides and Nucleic Acids

Learn about the structure, function, and significance of nucleotides and nucleic acids in biochemistry. Discover how DNA and RNA polymers are formed, their components, and the role of nucleotides as energy carriers. Understand the basics of DNA sequencing and RNA secondary structure.

jnader
Download Presentation

8. Nucleotides and Nucleic Acids

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 8. Nucleotides and Nucleic Acids Chapter 8 Lehninger 5th ed.

  2. Nucleotides • “Energy rich” compounds • Chemical signals • Enzyme co-factors • Nucleic Acids • DNA and RNA • Polymers of nucleotides • 3 components • Nitrogenous “base” • Ribose (or deoxyribose) • Phosphate

  3. “Bases” • 2 purine bases • Adenine: A • Guanine: G A G • Bases • Pyrimidines • Purines C T U • 2 pyrimidine bases (in DNA) • Cytosine: C • Thymine: T • orUracil: U • (in RNA, instead of Thymine)

  4. 5’ 1’ 4’ 3’ 2’ Ribose • carbons numbered: • 1’,2’,3’,4’,5’ • DNA: • 2’ Deoxyribose • or just deoxyribose

  5. Nucleotides SummaryDNA A,C,G,T deoxyriboseRNA A,C,G,U ribose

  6. Polymerise Nucleotides • nucleotides can be linked • phosphates linked to 2 pentoses • phosphodiester linkages • Link PO4 at • 5’ end to 3’ OH of next nucleotide • chain has POLARITY • distinct ends • 5’ end • 3’ end • usually “read” 5’ -> 3’

  7. Nucleotides as Energy Carriers • ATP • Adenosine triphosphate • ADP, AMP • Adenosine diphosphate • Adenosine monophosphate • ATP <--> ADP + PO4 • ADP <--> AMP + PO4 • Main energy exchange reactions in cells

  8. Structure of DNA? • The Genetic Material • Crick and Watson • Race with Linus Pauling to predict structure • Chargaff’s rules: • Chemical analysis: [A] = [T] [G] = [C] • Constant • for each organism • over time • across all tissues

  9. X-Ray Diffraction • Predict • Double helix • 2 periodicities • 3.4Å • 34Å

  10. Base Pairing • A – T basepair • 2 h-bonds • G – C basepair • 3 h-bonds • 2 anti-parallelDNA strands

  11. The Double Helix • 3.4Å per basepair • 10 basepairs per turn • 10-11 in aqueous solution • 2 anti-parallel strands

  12. DNA Replication • By DNA Polymerase

  13. RNA • Usually single stranded • Genetic material of RNA virus • Functional: • e.g. Translation machinery • rRNA (ribosomal RNA) • tRNA (transfer RNA) • Regulatory: • Control of gene expression • miRNA (microRNA) • Gene Expression • mRNA (messenger RNA) • Copy of 1 gene for translation by ribosomes

  14. RNA Secondary Structure • RNA single stranded • Can form base pairs internally

  15. RNA Secondary Structure • Many functional RNAs have secondary structure • G-U basepairs allowed

  16. DNA Sequencing

  17. DNA Sequencing

More Related