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Deoxyribonucleic Acid ( DNA )

Deoxyribonucleic Acid ( DNA ). Stanley Mikles, 2009. DNA is a polymer a polymer is a long chain molecule made up of many smaller molecules. a DNA polymer is a long chain of nucleotides. Parts of a nucleotide. Deoxyribose sugar. Nitrogen base. Phosphate. Phosphate. O. HO. P. O. HO.

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Deoxyribonucleic Acid ( DNA )

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  1. Deoxyribonucleic Acid (DNA) Stanley Mikles, 2009

  2. DNA is a polymer a polymer is a long chain molecule made up of many smaller molecules

  3. a DNA polymer is a long chain of nucleotides

  4. Parts of a nucleotide Deoxyribose sugar Nitrogen base Phosphate

  5. Phosphate O HO P O HO

  6. Deoxyribose Sugar O C C H H H H C C OH H

  7. Nitrogen Base N O NH2 C C N OH C

  8. Composition of a Nucleotide 1. Deoxyribose sugar 2. phosphate group 3. 1 - nitrogenous base a. thymine b. adenine c. cytosine d. guanine

  9. Thymine O CH3 H N N O H

  10. Adenine H N N H N N H N

  11. Cytosine H H N N N O H

  12. Guanine N O N H N H N N H H

  13. 1 of 4 possible Nucleotides O HO P O CH2 O O N O Phosphate N N H N N H OH H H Deoxyribose Guanine (one of 4 possible nitrogen bases)

  14. Steps of Replication of DNA A. molecule untwists B. enzymes break hydrogen bonds between nitrogen bases (enzyme: DNA polymerase) C. other enzymes bond new nucleotides to the split strand of the DNA D. Result is 2 separate identical molecules of DNA E. new molecules of DNA retwist

  15. A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T C T C A A TG C T G T A C G C C T A A T T G G C G C T G A T T T A G

  16. A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T C T C A A TG C T G T A C G C C T A A T T G G C G C T G A T T T A G A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T C T C A A TG C T G T A C G C C T A A T T G G C G C T G A T T T A G

  17. Making Proteins from DNA “Protein Synthesis” Proteins are polymers of amino acids. Remember: a polymer is a long chain molecule made up of many smaller molecules Proteins are long molecules made up of amino acids molecules.

  18. The whole point of DNA is to be a template for making proteins.

  19. There are 20 amino acids.

  20. Transcription of DNA to RNA (Think of transcription like re-writing a language into another form. It is the same language.)

  21. Ribonucleic Acid Single stranded Has uracil in place of thymine Three types of RNA

  22. Three types of RNA Messenger RNA mRNA Transfer RNA tRNA Ribosomal RNA rRNA

  23. Steps of Transcription 1. Enzyme unzips DNA molecule at the start codon and stopping at the first stop codon. A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T T A C G C C T A A T T G G C G C T G A T T T C A A TG C T G T A

  24. DNA polymerase cuts bonds between nitrogen bases

  25. 2. Free RNA nucleotides in Nucleoplasm form complementary base pairs on DNA strand forming an mRNA (messenger RNA) strand A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T T A C G C C T A A T T G G C G C T G A T T T C A A TG C T G T A A U G C G G AU U A U C C G C G U C U A A

  26. RNA nucleotides bonding to DNA

  27. 3. mRNA strand breaks away from DNA by enzyme action A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T T A C G C C T A A T T G G C G C T G A T T T C A A TG C T G T A A U G C G G AU U A U C C G C G U C U A A

  28. 4. DNA re-zips as • mRNA breaks off. A G T T A C G A C A T G C G G A T T A A C C G C G A C T A A A T T A T C A A TG C T G T A C G C C T A A T T G G C G C T G A T T

  29. mRNA strand breaks away

  30. DNA Rezips

  31. B. RNA Processing 1. Not all nucleotides in DNA code for making proteins. 2. Some regions of a DNA molecule do not code for anything. 3. These regions are called introns (intervening regions). 4. Regions that do contain information for coding for proteins are called exons.

  32. 5. When mRNA in transcribed from DNA, both introns and exons are copied. a. The introns must be removed from the mRNA before it can function as a protein b. Enzymes in nucleoplasm cut out the introns and paste mRNA back together. 6. mRNA then leaves the nucleus

  33. From RNA to protein translation: changing mRNA code into a protein: a sequence of amino acids

  34. Think of translation as re-writing a message into another language. The message is the same, but the language is different.

  35. 1. Transfer ribonucleic acid (tRNA) a. about 75 nucleotides long b. twisted so that only three nucleotides are available for bonding c. one tRNA for one amino acid

  36. Met A U G C G G A U U A U C C G C G U C U A A

  37. Amino Acid Transfer Ribonucleic Acid tRNA Anticodon

  38. 20 Amino Acids Scientists have found a few more amino acids, like pyrrolysine and selenocysteine, that help to build proteins.

  39. 2. start codon on mRNA strand attaches to ribosome

  40. 3. tRNA molecules, each carrying an amino acid, approach ribosome 4. tRNA molecules with complementary anticodon pairs with mRNA codon. 5. tRNA remains until next tRNA arrives

  41. 6. mRNA shifts along ribosome to next codon 7. Next tRNA molecule carrying the amino acid that possesses the complimentary anticodon bonds

  42. 8. An enzyme joins the two amino acids forming a peptide bond between them 9. tRNA from 1st amino acid falls away

  43. 10. process continues until ribosome reaches stop codon bringing about termination

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