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Nucleotides, Nucleic Acids and Heredity PowerPoint Presentation
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Nucleotides, Nucleic Acids and Heredity

Nucleotides, Nucleic Acids and Heredity

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Nucleotides, Nucleic Acids and Heredity

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  1. Nucleotides, Nucleic Acids and Heredity

  2. Nucleic Acids • Introduction • Each cell has thousands of different proteins • Proteins made up from about 20 AA • Information for protein comes from parent organism - “heredity” • This information is contained in the chromosomes in the nucleus of the cell • Genes inside the chromosomes carry specific information

  3. Genes • Genes • Carry specific information regarding how to construct proteins • Lie in sequences along the chromosomes Genes are made up of Nuceic Acids: There are Two types of Nucelic Acids • DNA • RNA • The information that tells the cell which proteins to manufacture is carried in the molecules of DNA

  4. Nucleic Acids • Components of Nucleic Acids • RNA or ribonucleic acid • NOT found in chromosomes • 6 types of RNA • polymeric nucleotides • DNA or deoxyribonucleic acid • present in chromosomes • polymeric nucleotides

  5. Nucleic Acids • Nucleotides are composed of: • a base • a sugar • a phosphate 3

  6. Bases • Bases found in DNA and RNA • All basic because they are heterocyclic amines • Uracil (U) found only in RNA • Thymine (T) found only in DNA • DNA = A, G, C, T • RNA = A, G, C, U

  7. Bases • Bases found in DNA and RNA Purines Pyrimidines

  8. Sugars • RNA contains D-ribose • DNA contains D-deoxyribose HO CH OH 2 O OH OH -ribose D Found in RNA Found in DNA

  9. Nucleosides • Nucleoside = sugar + base A Nucleoside

  10. Nucleosides • Nucleoside = sugar + base A Nucleoside

  11. Nucleosides • Nucleoside = sugar + base A Nucleoside

  12. Nucleosides Base + Sugar = Nucleoside • Adenine Adenosine • Guanine Guanosine • Thymine Thymidine • Cytosine Cytidine • Uracil Uridine

  13. Phosphate • AMP, ADP, ATP

  14. Nucleotides adenine ribose monophosphate BASE SUGAR PO43-

  15. NucleoSIDE ugar Nucleotides adenine ribose monophosphate BASE SUGAR PO43- adenosine

  16. NucleoSIDE ugar NucleoTIDE hree parts Nucleotides adenine ribose monophosphate BASE SUGAR PO43- adenosine adenosine monophosphate

  17. Nucleotides Nucleoside+ PO43- = Nucleotide • Adenosine Deoxyadenosine 5’-monophosphate (dAMP) • CytidineDeoxycytidine 5’-monophosphate (dCMP) • Uridine(in RNA)Uridine 5’-monophosphate (UMP) - or - • Thymidine(+ 2 PO43- )Deoxythymidine 5’-diphosphate (dTDP) • Guanosine(+ 3 PO43- ) Deoxyguanosine 5’-triphosphate (dGTP)

  18. DNA - Primary Structure • The primary structure is based on the sequence of nuclotides • 1) The Backbone is made from Ribose (sugar) and Phosphate • PO43- connected at Ribose 3’ and 5’ • 2) The Bases (AGTC, AGUC) are side-chains and are what makes each monomer unit different. • Bases connected at Ribose 1’

  19. DNA - Primary Structure

  20. DNA - Primary Structure

  21. DNA - Primary Structure

  22. P G S P T S P A S P C S P T S DNA - Primary Structure Where: S = ribose P = phosphate G,T,A,C = bases

  23. DNA - Primary Structure • The order of the bases (-ATTGAC-) provides the primary structure of DNA. • The backbone of both DNA and RNA consists of alternating sugar and phosphate groups • there is a 3’ end and a 5’ end • the backbone adds stability to the structure

  24. P G S P T S P A S P C S P T S DNA - Primary Structure • Erwin Chargaff (1905- ) DNA always had ratios constant: moles adenine = moles thymine moles guanine = moles cytosine • Base Pairing of: • A-T or T-A • G-C or C-G

  25. How we Depict DNA

  26. How we Depict DNA

  27. DNA – Secondary Structure • James Watson (1928- ) and Francis Crick (1916-2004 ) • Established 3-D structure of DNA • Bases on adjacent strands PAIRED so that Hydrogen bonds formed: Complementary Base Pairing

  28. DNA - Secondary Structure • Complementary Base Pairing • Adenine pairs with Thymine • Position of H bonds and distance match

  29. DNA - Secondary Structure • Complementary Base Pairing • Guanine pairs with Cytosine • Position of H bonds and distance match

  30. DNA - Secondary Structure • Complementary Base Pairing

  31. DNA - Secondary Structure DNA structure led to explanation of the transmission of heredity

  32. DNA vs. RNA • DNA and RNA differences: 1) DNA 4 bases AGCT RNA 4 bases AGCU 2) DNA sugar deoxyribose RNA sugar ribose 3) DNA is almost always double stranded RNA is single stranded A pairs with U (not T)

  33. DNA Replication • Each gene is a section of DNA • 1000-2000 base sequences • Each gene codes for 1 protein molecule • Each cell contains ALL of the info for the organism • Replication is the process of copying all genetic information on the DNA to new DNA

  34. DNA Replication Steps • Opening of the superstructure • Relaxing the higher order structure • Unwinding the DNA double helix • Primer/Primase – initiate the replication • DNA polymerase – enzyme that adds the nucleotides to the chain – Pairing A-T G-C • Ligation – Joining of Okazaki fragments and completion of the molecule

  35. DNA Replication • View animations……… • http://www.youtube.com/watch?v=4PKjF7OumYo • http://www.youtube.com/watch?v=hfZ8o9D1tus • http://www.youtube.com/watch?v=Luw5_z8mIrI • http://www.youtube.com/watch?v=nIwu5MevZyg

  36. DNA Replication • Semiconservative Replication • The result is 4 strands of DNA • Only half of each helix is “new” • Semiconservative since one half of each new helix is a daughter strand and half a parent

  37. DNA Replication

  38. DNA Replication

  39. DNA Replication Okazaki fragments

  40. DNA Replication Okazaki fragments

  41. Types of RNA • mRNA - Messenger RNA • tRNA - Transfer RNA • rRNA - Ribosomal RNA • snRNA – Small nuclear RNA • miRNA – Micro RNA • siRNA – Small interfering RNA (1933)

  42. mRNA • Messenger RNA • Carries info from DNA to cytoplasm • Not stable (not long lasting) • Info is for single protein synthesis • Exactly complementary to one DNA strand

  43. tRNA • Transfer RNA (tRNA) • Transfers amino acids to the point of protein synthesis • Small (73-93 nucleotides) • About 20 exist (one for each AA!) • “L-shaped” • Contain some “other” modified Nucleic Acids

  44. Transfer RNA

  45. rRNA • Ribosomal RNA (rRNA) • Found in ribosomes • 35% protein, 65% rRNA make up ribosomes • Large molecules with MW=1,000,000 • Protein synthesis takes place on ribosomes

  46. RNA • snRNA – Small nuclear RNA • Helps with the processing of the mRNA transcribed from DNA • miRNA – Micro RNA • Important in the timing of organism development • siRNA – Small interfering RNA • Help control Gene expression

  47. Transmission of Information • Step 1 - Transcription • Copying the “code” from DNA to to mRNA • The mRNA then moves to the ribosome • Step 2 - Translation • Deciphering the “code” from mRNA into protein • Each 3 nucleotides code for a specific AA • Next Chapter Discussion!!!!!!!!!!

  48. REPLICATION DNA DNA TRANSCRIPTION mRNA TRANSLATION amino acids protein ! Transmission of Information • SUMMARY