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7.2 Transcription 

Initiation

  • RNA polymerase binds to template DNA at promoter (sequence before start of gene) by recognizing TATA (lost of A, T)

  • DNA strands are seperated (like helicase)

Elongation

  • RNA polymerase synthesizes complementary RNA strands 3’ direction

  • no primer necessary

  • while DNA is opened, many RNA polymerases may be active synthesizing many RNA strands

Termination

  • RNA polymerase recognizes termination sequence and dissociates from DNA

  • RNA also dissociates and leaves nucleus via nuclear pores into cytosol

Post-Transcription Modifications

  • RNA known as pre-mRNA

  • Must me modified before it can leave the nucleus

    • addition of poly-A tail

    • prevents degredation

  • Removal of introns (non-coding regions) and splicing of exons (coding regions )

    • makes mRNA functional

    • alternative splicing can produce difference mRNAs from the same pre-mRNA

Modifications

AV

7.2 Transcription 

Initiation

  • RNA polymerase binds to template DNA at promoter (sequence before start of gene) by recognizing TATA (lost of A, T)

  • DNA strands are seperated (like helicase)

Elongation

  • RNA polymerase synthesizes complementary RNA strands 3’ direction

  • no primer necessary

  • while DNA is opened, many RNA polymerases may be active synthesizing many RNA strands

Termination

  • RNA polymerase recognizes termination sequence and dissociates from DNA

  • RNA also dissociates and leaves nucleus via nuclear pores into cytosol

Post-Transcription Modifications

  • RNA known as pre-mRNA

  • Must me modified before it can leave the nucleus

    • addition of poly-A tail

    • prevents degredation

  • Removal of introns (non-coding regions) and splicing of exons (coding regions )

    • makes mRNA functional

    • alternative splicing can produce difference mRNAs from the same pre-mRNA

Modifications

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