How Do We Get Proteins? - PowerPoint PPT Presentation

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How Do We Get Proteins?
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How Do We Get Proteins?

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  1. How Do We Get Proteins? http://www.math.fsu.edu/~quine/IntroMathBio_04/Proteins/myoglobin_geis.jpg myoglobin

  2. When DNA copies….. • It copy's in a very specific order. It copies 5’-3’ from a 3’-5’ Template.

  3. HUH?!?!

  4. That means the DNA strand is in the following order… DNA

  5. That means the DNA strand is in the following order…

  6. That means the DNA strand is in the following order…

  7. That means the DNA strand is in the following order…

  8. That means the DNA strand is in the following order…

  9. That means the DNA strand is in the following order…

  10. Double Helix

  11. Nucleotides: basic molecule of DNA Pyrimidine

  12. Nucleotides: basic molecule of DNA Purine

  13. Pyrimidines and Purines Made up of a • Sugar (5 carbon) • Phosphate group • Nitric Base

  14. DNA Replication • http://www.johnkyrk.com/DNAreplication.html

  15. Our Friend RNA

  16. Differences between RNA and DNA • RNA has only a SINGLEStrand (DNA is Double Stranded) • RNA contains ribose instead of deoxyribose • RNA polymerase can start the RNA transcription without a primer

  17. Differences between RNA and DNA • RNA uses Uracil(U) instead of Thymine(T) • More errors occur in an RNA copy than in DNA copy of nucleotides (103 more than in DNA) • FACT: DNA has a transcription error approximately every 107 nucleotides. RNA has an error approximately every 104 !

  18. Differences between RNA and DNA • WHY are there more errors in RNA Transcription? • One of several reasons is that in rare instances Uracil can also bond with Guanine

  19. Is this a Bad thing? • WHY are there more errors in RNA Transcription? • One of several reasons is that in rare instance Uracil can also bond with Guanine • RNA is a temporary copy in Eukaryotes

  20. Types of RNA mRNA • mRNA= messenger RNA • codes for a protein

  21. Types of RNA tRNA • tRNA= transfer RNA • central to protein synthesis as adaptors between mRNA and amino acids

  22. Types of RNA rRNA • rRNA= ribosomal RNA • form the basic structure of the ribosome and catalyze protein synthesis

  23. How Do We Get Protiens?

  24. Transcription- the synthesis of RNA under DNA (occurs in the nucleus) • Translation- the actual synthesis of a polypeptide coded for by the mRNA. (changing the base sequence of the mRNA molecule into a chain of amino acids that form a polypeptide. For our purposes a protein.)

  25. An mRNA copy is made from DNA in the Nucleus

  26. The DNA strand from which the mRNA is copied is the TEMPLATE STRAND

  27. The mRNA leaves the nucleus and enters a ribosome (made up of rRNA)

  28. tRNA collects a specific amino acids present in the cell and brings it to the ribosome

  29. The anticodon of the tRNA matches up with its counterpart codon on the mRNA

  30. When the mRNA & the tRNA link up the amino acid detaches and is connected to the adjacent amino acid

  31. This chain of amino acids is a protein (polypeptide)

  32. rRNA Ribosome

  33. rRNA mRNA enters the “A” site of the ribosome

  34. rRNA When the first codon reaches the “P” site the tRNA brings down the amino acid and links up with the mRNA

  35. rRNA The “E” site is where the amino acid separates form the tRNA and links up to adjacent amino acids. This is where the MRNA and tRNA leave the ribosome

  36. ANTICODONS tRNA • Anticodons specify which amino acid a tRNA collects • The anticodon then pairs up with its corresponding codon Anticodon

  37. ANTICODONS tRNA • So for example... • The anticodon AGU would pair with the codon UCA. • THEY ARE OPPOSITES OF EACH OTHER Anticodon

  38. So What's a codon? Codon • This basic unit of genetic code is 3 nucleotides long • It specifies a specific amino acid • Each codon only specifies 1 amino acid (BUT…an amino acid may have several different codons that code for it)

  39. http://images.google.com/imgres?imgurl=http://biology.kenyon.edu/courses/biol114/Chap05/trna-1.gif&imgrefurl=http://biology.kenyon.edu/courses/biol114/Chap05/Chapter05.html&h=382&w=283&sz=37&tbnid=G8z7JoxTdy0J:&tbnh=119&tbnw=88&hl=en&start=5&prev=/images%3Fq%3DtRNA%26svnum%3D50%26hl%3Den%26lr%3D%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official_s%26sa%3DGhttp://images.google.com/imgres?imgurl=http://biology.kenyon.edu/courses/biol114/Chap05/trna-1.gif&imgrefurl=http://biology.kenyon.edu/courses/biol114/Chap05/Chapter05.html&h=382&w=283&sz=37&tbnid=G8z7JoxTdy0J:&tbnh=119&tbnw=88&hl=en&start=5&prev=/images%3Fq%3DtRNA%26svnum%3D50%26hl%3Den%26lr%3D%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official_s%26sa%3DG

  40. THE END http://www.chemistry.emory.edu/faculty/lynn/research/dna/template.gif

  41. When DNA copies….. • It copy's in a very specific order. It copies 5’-3’ from a 3’-5’ Template.

  42. HUH?!?!

  43. That means the DNA strand is in the following order… DNA

  44. That means the DNA strand is in the following order…

  45. That means the DNA strand is in the following order…

  46. That means the DNA strand is in the following order…

  47. That means the DNA strand is in the following order…

  48. That means the DNA strand is in the following order…