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DNA and RNA

DNA and RNA. Replication, Transcription and Translation. Griffith’s Experiment. Avery’s Experiment. Hershey-Chase Experiment. A typical Bacteriophage – . Bacteriophage infection cycle. The 3 Key Roles of DNA. Storing genetic information. Copying genetic information.

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DNA and RNA

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  1. DNA and RNA Replication, Transcription and Translation

  2. Griffith’s Experiment

  3. Avery’s Experiment

  4. Hershey-Chase Experiment

  5. A typical Bacteriophage –

  6. Bacteriophage infection cycle

  7. The 3 Key Roles of DNA • Storing genetic information. • Copying genetic information. • Transmitting genetic information.

  8. DNA is 2 long polymers of covalently bonded nucleotides wound around each other and attracted to each other by hydrogen bonds.

  9. The 4 bases are the Purines adenine and guanine and the Pyrimidines Thymine and Cytosine

  10. Guanine bonds with Cytosine. The three bonds are hydrogen bonds!

  11. Adenine bonds with Thymine. Here there are two hydrogen bonds.

  12. A diagram of DNA

  13. The three components of DNA are the phosphate group, sugar and a nitrogen containing base

  14. Chargaff's rules state that DNA from any cell of all organisms should have a 1:1 ratio of guanine to cytosine and adenine to thymine.

  15. Rosalind Franklin and her X-Ray diffraction picture of DNA

  16. Watson and Crick – 1953. DNA is 2 chains wound around each other, each chain going in opposite directions. The two chains are held together with hydrogen bonds.

  17. Prokaryote vs. Eukaryote DNA.

  18. Eukaryotic chromosomes contain DNA wrapped around proteins called histones. Each package of 8 histones is called a nucleosome

  19. The strands are complementary in the sense that each strand can be used to make the other half by the sequence of base pairing.

  20. Prokaryote DNA replication

  21. Eukaryotes – DNA replication occurs at many places and proceeds in two directions until each chromosome is copied.

  22. DNA Replication is carried out by a series of enzymes.DNA Polymerase joins individual nucleotides to produce a new DNA molecule

  23. Gene – coded DNA instruction for the production of a protein.

  24. Protein Synthesis an overview • http://www.youtube.com/watch?v=suN-sV0cT6c

  25. The three main types of RNA

  26. DNA and RNA nucleotides are very similar in structure.

  27. Acentral tenet of biology describes the two-step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → protein.

  28. Because there is no nucleus to separate the processes of transcription and translation, when bacterial genes are transcribed, their transcripts can immediately be translated

  29. Transcription and translation are spatially and temporally separated in eukaryotic cells; that is, transcription occurs in the nucleus to produce a pre-mRNA molecule

  30. Transcription – the production of RNA molecules from parts of the DNA molecule

  31. Promoters are regions of DNA that tell RNA polymerase where to start. Similar signals tell RNA polymerase to stop

  32. .The pre-mRNA is processed in the nucleus to remove the introns and splice the exons together into a translatable mRNA. That mRNA exits the nucleus and is translated in the cytoplasm.

  33. The steps of pre-mRNA splicing (intron removal)

  34. The basic building block of a protein is the amino acid.

  35. There are 20 amino acids; each one differs in its R group.Below are four amino acids showing the differences in R groups.

  36. Amino acids are joined together in proteins by peptide bonds.

  37. The language of RNA to the language of protein: The genetic code is a triplet code in which three nucleotides in RNA specify one amino acid in protein.

  38. Translation is the process of decoding an mRNA message into a polypeptide chain. It all starts with mRNA

  39. Ribosomes, the organelles on which the mRNA is translated, consist of two subunits, each of which contains rRNA and ribosomal proteins.

  40. tRNA’s bring amino acids to the ribosomes during translation to be assembled into polypeptide chains.

  41. Adding an Amino Acid to tRNAThe correct amino acid is added with the help of an enzyme.

  42. Initiation of Translation

  43. Translation begins when an mRNA attaches to a ribosome.Each codon is matched by an anticodon with tRNA. The tRNA brings in the correct amino acid for that codon.

  44. Elongation of the polypeptide chain begins by the appropriate tRNAbinding to the codon in the A site of the ribosome

  45. At a stop codon, a release factor reads the triplet, and polypeptide synthesis ends

  46. Several ribosomes can translate an mRNA at the same time, forming what is called a polysome.

  47. http://www.youtube.com/watch?v=5iS4CRPPDus

  48. genetics, a mutation is a change of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal genetic element.

  49. A frameshift mutation (also called a framing error or a reading frame shift) is a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three.

  50. Cystic Fibrosis is an example of a frame shift mutation.

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