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Central Dogma DNA  RNA  Protein

Central Dogma DNA  RNA  Protein. …..Which leads to Traits. How Does DNA produce traits?. 1. Genes control proteins which determine traits 2. Order of nucleotides in the DNA determines amino acid sequence RNA's act as 'go-between' for DNA

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Central Dogma DNA  RNA  Protein

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  1. Central DogmaDNA  RNA  Protein

  2. …..Which leads to Traits

  3. How Does DNA produce traits? 1. Genes control proteins which determine traits 2. Order of nucleotides in the DNA determines amino acid sequence • RNA's act as 'go-between' for DNA • Gene- a sequence of DNA with a specific function

  4. RNA • Single strand of nucleotides (unlike DNA) • Contains 5-C sugar ribose • Uracil replaces Thymine • 3 types of RNA produced 1. Messenger RNA (m-RNA) - code for order of amino acids 2. Transfer RNA (t-RNA) - carry amino acids and fit them in proper place 3. Ribosomal RNA (r-RNA) - major component of ribosome; large and small subunits a. P site: carries the growing polypeptide chain b. A site: delivers the next amino acid to the growing chain

  5. Codons • Codons – 3 nucleotide sequences coded from the original DNA strand onto a mRNA strand. • Each codon corresponds to an amino acid or a stop/start signal • The codon on a mRNA strand is complementary to an anti-codon on tRNA

  6. Codons in mRNA

  7. Going from DNARNA • Transcription - Formation of m-RNA molecule from a DNA template – occurs in the nucleus. • Occurs in three steps: • Initiation • Elongation • Termination

  8. Initiation • RNA polymerases bind to DNA at regions called promoters (initiation site, also called TATA box); the enzyme then separates the 2 DNA strands and transcription begins. • RNA polymerase reads DNA from 3’ to 5’

  9. Elongation • RNA polymerases move along the DNA and: -untwists and opens a short segment of DNA (DNA template) - links incoming RNA nucleotides to the 3' end of the elongating strand; RNA grows one nucleotide at a time in the 5' to 3' direction

  10. Termination Transcription proceeds until RNA polymerases reaches a termination site on the DNA; RNA molecule is then released and leaves the nucleus. The DNA strand then joins back together – unchanged.

  11. Translation • Translation – using the mRNA strand made during Transcription and tRNA and rRNA to build a protein. • Occurs at the site of protein synthesis – the ribosome. • Occurs in three steps – the same but different than transcription – initiation, elongation, and termination.

  12. Initiation 1. the small ribosomal subunit attaches to the 5' end of the mRNA ('start' codon -AUG) 2. a tRNA (with anticodon UAC) carries the amino acid methionine to the mRNA

  13. Elongation 1. the next tRNA binds to the ribosome; the new amino acid is attached to first one 2. the first tRNA is released and binds again with other amino acids (repeated deliveries) 3. a new tRNA attaches to the ribosome and repeats the process, thereby increasing the polypeptide chain length

  14. Termination • Occurs when the ribosome encounters a 'stop' codon. • The resulting protein formed is now released and is used by the cell.

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