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DNA

DNA. Introduction. Do you think DNA is important?. T.V shows Movies Biotech Films News Cloning Genetic Engineering. DNA. DNA cont. At the most basic level DNA is a set of instructions for protein construction. Structural Enzymes Hormones. What do you need to know?.

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DNA

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  1. DNA Introduction

  2. Do you think DNA is important? • T.V shows • Movies • Biotech Films • News • Cloning • Genetic Engineering

  3. DNA

  4. DNA cont. • At the most basic level DNA is a set of instructions for protein construction. • Structural • Enzymes • Hormones

  5. What do you need to know? • Structure of DNA • How DNA replicates (reproduces)? • How DNA transcribes RNA? • How Ribosomes use the RNA to correctly assemble proteins?

  6. Watson and Crick • Nobel Peace Prize • The Double Helix, 1953 • Outlined the Structure of the DNA • Discovered the “locking” of bases

  7. DNA Structure • DNA is a polymer. Each nucleotide consists of a 5-carbon sugar (deoxyribose), a nitrogen containing base attached to the sugar, and a phosphate group. • There are four different types of nucleotides found in DNA, differing only in the nitrogenous base. The four nucleotides are given one letter abbreviations as shorthand for the four bases. • A is for adenine • G is for guanine • C is for cytosine • T is for thymine

  8. DNA Replication • DNA Replication Website • Produces 2 exact copies of DNA • Occurs just prior to cell division

  9. Steps of DNA Replication

  10. PROTEIN SYNTHESIS

  11. Protein Synthesis • The production (synthesis) of proteins. • 3 phases: 1. Transcription 2. RNA processing 3. Translation • Remember: DNA  RNA  Protein

  12. Nuclear membrane DNA Transcription RNA Processing mRNA Ribosome Translation Protein DNA  RNA Protein Eukaryotic Cell

  13. Question: • How does RNA(ribonucleic acid) differ from DNA (deoxyribonucleic acid)?

  14. RNA differs from DNA 1. RNA has a sugar ribose DNA has a sugar deoxyribose 2. RNA contains uracil (U) DNA has thymine (T) 3. RNA molecule is single-stranded DNA is double-stranded 4. RNAmolecule leaves the nucleus DNAstays in the nucleus 5. RNA is like a page/recipe DNA is like the whole book

  15. Nuclear membrane DNA Transcription RNA Processing mRNA Ribosome Translation Protein 1. Transcription Eukaryotic Cell

  16. 1. Transcription • The transfer of information in the nucleus from a DNA molecule to an RNA molecule. • Only 1 DNA strand serves as the template • When complete, RNA molecule can be processed & released to the ribosomes.

  17. Question: • What is the enzyme responsible for the production of the RNA molecule?

  18. Answer: RNA Polymerase • Separates the DNA molecule by breaking the H-bonds between the bases. (Unzips the DNA) • Then moves along one of the DNA strands and lines up complementRNAnucleotides with DNA. • Bonds the sugar and phosphate groups of the RNA together. Does not bond the nitrogenous bases. • RNA leaves the area between the DNA strands. • DNAzips back up. • RNA is processed and leaves the nucleus.

  19. DNA RNA Polymerase mRNA in construction 1. Transcription

  20. Question: • What would be the complementary RNA strand for the following DNA sequence? • DNA GCGTATG

  21. Answer: • DNA GCGTATG • RNA CGCAUAC

  22. Nuclear membrane DNA Transcription RNA Processing mRNA Ribosome Translation Protein 2. RNA Processing Eukaryotic Cell

  23. Types of RNA • Types ofRNA: A. messenger RNA (mRNA) B. transfer RNA (tRNA) • Remember: all produced in thenucleus!

  24. 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.

  25. 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)

  26. B. Transfer RNA (tRNA) • Made up of 75 to 80 nucleotides long. • Picks up the appropriate amino acid floating in the cytoplasm • Transports amino acids to the mRNA. • Have anticodons that are opposites to mRNAcodons. • Recognizes the appropriate codons on the mRNA and bonds temporarily to them

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

  28. Nuclear membrane DNA Transcription RNA Processing mRNA Ribosome Translation Protein 3. Translation Eukaryotic Cell

  29. 3. Translation • Synthesis of proteins in the cytoplasm • Involves the following: 1. mRNA (codons) 2. tRNA (anticodons) 3. ribosomes 4. amino acids

  30. 3. Translation • Three parts: 1. initiation: start codon (AUG) 2. elongation: building the polypeptide chain 3. termination: stop codon (UAG) • Let’s make a PROTEIN!!!!.

  31. mRNA A U G C U A C U U C G 3. Translation Large subunit Small subunit

  32. aa2 aa1 2-tRNA 1-tRNA G A U U A C Initiation anticodon A U G C U A C U U C G A hydrogen bonds codon mRNA

  33. aa3 3-tRNA G A A Elongation peptide bond aa1 aa2 1-tRNA 2-tRNA anticodon U A C G A U A U G C U A C U U C G A hydrogen bonds codon mRNA

  34. aa3 3-tRNA G A A aa1 peptide bond aa2 1-tRNA U A C (leaves) 2-tRNA G A U A U G C U A C U U C G A mRNA Ribosomes move over one codon

  35. aa4 4-tRNA G C U peptide bonds aa1 aa2 aa3 2-tRNA 3-tRNA G A U G A A A U G C U A C U U C G A A C U mRNA

  36. aa4 4-tRNA G C U peptide bonds aa1 aa2 aa3 2-tRNA G A U (leaves) 3-tRNA G A A A U G C U A C U U C G A A C U mRNA Ribosomes move over one codon

  37. aa5 5-tRNA U G A peptide bonds aa1 aa2 aa4 aa3 3-tRNA 4-tRNA G A A G C U G C U A C U U C G A A C U mRNA

  38. aa5 5-tRNA U G A peptide bonds aa1 aa2 aa3 aa4 3-tRNA G A A 4-tRNA G C U G C U A C U U C G A A C U mRNA Ribosomes move over one codon

  39. aa5 aa4 Termination aa199 aa200 aa3 primary structure of a protein aa2 aa1 terminator or stop codon 200-tRNA A C U C A U G U U U A G mRNA

  40. aa5 aa4 aa3 aa2 aa199 aa1 aa200 End Product • The end products of protein synthesis are the primary structure of a protein. • A sequence of amino acid bonded together by peptide bonds.

  41. Question: • The anticodon UAC belongs to a tRNA that recognizes and binds to a particular amino acid. • What would be the DNA base code for this amino acid?

  42. Answer: • tRNA - UAC (anticodon) • mRNA - AUG (codon) • DNA - TAC

  43. incoming large subunit 1 2 3 4 5 6 7 mRNA incoming small subunit polypeptide Polyribosome • Groups of ribosomes reading same mRNA simultaneously producing many proteins (polypeptides).

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