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Gene

Gene. Entire nucleic acid sequence necessary for the synthesis of a functional polypeptide (protein chain) or functional RNA. Nucleic Acid Sequence. 1. DNA (Deoxyribo Nucleic Acid) 2. RNA (Ribo Nucleic Acid). DNA as Genetic Material. DNA encodes all the information in the cell

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Gene

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  1. Gene Entire nucleic acid sequence necessary for the synthesis of a functional polypeptide (protein chain) or functional RNA Nucleic Acid Sequence 1. DNA (Deoxyribo Nucleic Acid) 2. RNA (Ribo Nucleic Acid)

  2. DNA as Genetic Material • DNA encodes all the information in the cell • The composition of the DNA is the same in all cells within an organism • Variation among different cells is achieved by reading the DNA differently • DNA contains four bases that encode all the information to make an organism’s life

  3. How is Information Encoded in DNA? • DNA Consists of four kinds of bases (A,C,G,T) joined to a sugar phosphate backbone • Bases carry the genetic information while the phosphate backbone is structural • Two complementary strands of bases (C-G) and (A-T)

  4. DNA is a Polymer of Deoxyribonucleotide Units DEOXYRIBONUCLEOTIDE DEOXYRIBONUCLEOTIDE

  5. Deoxyribonucleic Acid (DNA) Nucleotide: • Phosphate group • 5-carbon sugar • Nitrogenous base

  6. Phosphate Group O O=P-O O 5 CH2 O N Nitrogenous base (A, G, C, or T) C1 C4 Sugar (deoxyribose) C3 C2 DNA Nucleotide

  7. “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone DNA Double Helix

  8. 5 O 3 3 O P P 5 5 C O G 1 3 2 4 4 2 1 3 5 O P P T A 3 5 O O 5 P P 3 DNA Double Helix

  9. 9 9 Two Purines Adenine Guanine Two Pyrimidines 1 1 Thymine Cytosine DNA is Composed of Four Different Ribonucleotides

  10. A or G T or C Nitrogenous Bases • PURINES 1. Adenine (A) 2. Guanine (G) • PYRIMIDINES 3. Thymine (T) 4. Cytosine (C)

  11. 3 H-bonds G C BASE-PAIRINGS Base # of Purines Pyrimidines PairsH-Bonds Adenine (A)Thymine (T) A = T 2 Guanine (G)Cytosine (C) C G 3

  12. H-bonds G C A T BASE-PAIRINGS

  13. Base Pairing Occurs Through Hydrogen Bonds G-C A-T

  14. C T A G Chargaff’s Rule • Adenine must pair with Thymine • Guanine must pair with Cytosine • Their amounts in a given DNA molecule will be about the same.

  15. Deoxy ribo nucleotide Ribose= Five Carbon Sugar Molecule 5´ 5´ 1´ 1´ 4´ 4´ 2´ 2´ 3´ 3´ Ribose (RNA) Deoxyribose (DNA) Backbone Sugar Molecules

  16. 5´ 1´ 3´ 2´ 5´ 1´ 3´ 2´ 5´ 1´ 3´ 2´ The DNA Backbone is a Deoxyribose Polymer Deoxyribose sugars are linked by Phosphodiester Bonds 5´-p 3´-OH 5´ 3´

  17. 5´ 3´ 3´ 5´ 5´ 5´ 1´ 3´ 2´ 5´ 1´ 3´ 2´ 5´ 1´ 3´ 2´ 3´

  18. Base 5´ 5´ 1´ 1´ 3´ 3´ 2´ 2´ Base 5´ 5´ 1´ 1´ 3´ 3´ 2´ 2´ Base 5´ 5´ 1´ 1´ 3´ 3´ 2´ 2´

  19. DeoxyRibonucleotide Deoxyadenosine 5´-triphosphate (dATP) Deoxyadenosine DeoxyRibonucleoside

  20. T C T A 5´ 3´ G A 3´ 5´

  21. G C = A T

  22. Double-stranded DNA Forms a Double Helix

  23. Central Dogma of Biology

  24. DNA, RNA, and the Flow of Information Replication Translation Transcription

  25. Central Dogma (Modifications) (2)Ribozymes Transcription Translation Protein DNA RNA • Reverse • transcription Replication (2)Self Replication (3)Self Replication

  26. RNA • A polymer composed of nucleotides that contain the sugar ribose and one of the four bases cytosine, adenine, guanine and uracile • Polynucleotide containing ribose sugar and uracil instead of thymine • Genetic material of some viruses • Primary agent for transferring information from the genome to the protein synthetic machinery

  27. RNA • NUCLEIC ACID, • SINGLE STRAND, • PO4, • RIBOSE SUGAR. • BASE PAIRS (N): • U = URACIL • A=ADENINE • C=CYTOSINE • G=GUANINE

  28. URACIL (U) base with a single-ring structure phosphate group sugar (ribose)

  29. Types of RNA • Three types ofRNA: A. messenger RNA (mRNA) B. transfer RNA (tRNA) C. ribosome RNA (rRNA) • Remember: all produced in the nucleus!

  30. A. Messenger RNA (mRNA) • Carries the information for a specific protein. • Made up of 500 to 1000 nucleotides long. • Made up of codons (sequence of three bases: AUG - methionine). • Each codon, is specific for an amino acid.

  31. start codon A U G G G C U C C A U C G G C G C A U A A mRNA codon 1 codon 2 codon 3 codon 4 codon 5 codon 6 codon 7 stop codon protein methionine glycine serine isoleucine glycine alanine Primary structure of a protein aa2 aa3 aa4 aa5 aa6 aa1 peptide bonds A. Messenger RNA (mRNA)

  32. B. Transfer RNA (tRNA) • Made up of 75 to 80 nucleotides long. • Picks up the appropriate amino acid floating in the cytoplasm (amino acid activating enzyme) • Transports amino acids to the mRNA. • Have anticodons that are complementary to mRNAcodons. • Recognizes the appropriate codons on the mRNA and bonds to them with H-bonds.

  33. anticodon codon in mRNA anticodon amino acid attachment site amino acid OH tRNA MOLECULE amino acid attachment site

  34. The structure of transfer RNA (tRNA)

  35. amino acid attachment site methionine amino acid U A C anticodon B. Transfer RNA (tRNA)

  36. C. Ribosomal RNA (rRNA) • Made up of rRNA is 100 to 3000 nucleotides long. • Important structural component of a ribosome. • Associates with proteins to form ribosomes.

  37. Ribosomes • Large and small subunits. • Composed of rRNA (40%) and proteins (60%). • Both units come together and help bind the mRNA and tRNA. • Two sites fortRNA a. P site (first and last tRNA will attach) b. A site

  38. Ribosomes

  39. mRNA A U G C U A C U U C G Ribosomes Large subunit P Site A Site Small subunit

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