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Nucleic Acids

Nucleic Acids. Big Idea 3: Living systems store, retrieve, transmit, and respond to info essential to life processes. Essential Knowledge. 3A1: DNA, and in some cases RNA, is the primary source of heritable information. Nucleic Acids. Store and transmit hereditary information

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Nucleic Acids

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  1. Nucleic Acids Big Idea 3: Living systems store, retrieve, transmit, and respond to info essential to life processes.

  2. Essential Knowledge • 3A1: DNA, and in some cases RNA, is the primary source of heritable information.

  3. Nucleic Acids • Store and transmit hereditary information • Amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene • Genes are found on chromosomes.

  4. Nucleic Acids • Large, complex molecules composed of C, O, H, N, and P. • 2 types are RNA, ribonucleic acid and DNA, deoxyribonucleic acid.

  5. DNA

  6. RNA

  7. Prokaryotes • Earliest cells • Smaller than Eukaryotes! • No nucleus (home for DNA)

  8. Prokaryotic DNA • Is housed in a region called the nucleoid

  9. Prok. DNA • Is usually small and circular • Has plasmids: small, extra-chromosomal, double stranded, and circular DNA

  10. Viruses and Eukaryotes can have plasmids too…

  11. Herstory • Rosalind Franklin: British scientist (working in Maurice Wilkins lab) who took an X ray diffraction image of DNA, 1952 • Led to double helix shape discovery by Watson and Crick Photo 51

  12. HIStory • Watson and Crick used Franklin’s image to create the double helix DNA model in 1953. • Won Nobel Prize in 1962,w/ Wilkins. Double Helix Structure

  13. Nucleic Acid Structure • Made of nucleotides; both RNA and DNA. • Each nucleotide contains: • 1 Phosphate Group • 1 Sugar • 1 Nitrogen Base

  14. Phosphate • PO4 • Makes up a part of the DNA/RNA backbone

  15. Sugar • In DNA, sugar is deoxyribose • In RNA, sugar is ribose • Binds to Nitrogen Base • Is in backbone of DNA/RNA

  16. Fig. 5-27c-2 Sugars Ribose (in RNA) Deoxyribose (in DNA) (c) Nucleoside components: sugars

  17. DNA Nitrogen Bases • Adenine • Thymine • Guanine • Cytosine Conserved Through Evolution!

  18. DNA Base Pairing Rules (Chargaff’s Rules) • A only binds with T • C only binds with G • H bonds hold Nitrogen bases together

  19. RNA Nitrogen Bases • Adenine • Cytosine • Guanine • Uracil • NO Thymine!

  20. Fig. 5-27c-1 Nitrogenous bases Pyrimidines Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA) Pyrimidines: Single Ring Structure: CTU Purines Adenine (A) Guanine (G) Purines: Double Ring Structure, GA (c) Nucleoside components: nitrogenous bases

  21. DNA: Double Stranded, RNA Single Stranded

  22. DNA is AntiParallel

  23. Fig. 5-27ab 3’ carbon and 5’ carbon bind to PO4 phosphodiester linkage 5' end 5'C 3'C Nucleoside Nitrogenous base 5'C Phosphate group 3'C Sugar (pentose) 5'C 3'C (b) Nucleotide 3' end (a) Polynucleotide, or nucleic acid

  24. DNA Replication • DNA provides directions for its own replication  ensure continuous inheritance of DNA

  25. DNAReplication • Before a cell divides  must duplicate its DNA. • Each strand of DNA will serve as a template/model for a new strand of DNA (semiconservative).

  26. DNA Replication 1st Step • Enzyme called DNA helicase unzips and unwinds a portion of DNA. • Enzyme helps breaks apart H connect N bases. (A,T,C,G) DNA Helicase

  27. DNA Replication: 2nd Step • 2nd enzyme called DNA polymerase III comes along and begins to add complementary base pairs to nitrogen bases. • Works in 5’ to 3’ fashion… • Video Clip!

  28. DNA Replication Other Enzymes Involved: Ligase: Glues back sugar-phosphate backbone Topoisomerase: Regulates overwinding/ underwinding of DNA by cutting backbone

  29. http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter14/dna_replication.htmlhttp://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter14/dna_replication.html

  30. Practice! • If one side of DNA reads CTCT, what would the complement side of DNA read? Write down on paper!

  31. GAGA!

  32. Then, The Cell Divides… • Mitosis: Makes 2 identical diploid (2 copies of chromosomes) cells from 1 parent cell: IPMAT

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