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Nucleotides, Nucleic Acids and Heredity

Nucleotides, Nucleic Acids and Heredity. 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

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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

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