Synthesizes an mRNA complementary to template strand AUCG mRNA breaks off Given

Synthesizes an mrna complementary to template strand

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Synthesizes an mRNA complementary to template strand A,U,C,G mRNA breaks off Given 5’ cap and Poly A Tail mRNA = RNA equivalent of the CODING strand T’s are replaced with U’s End: mRNA The Basics of Translation: Start: mRNA (produced in transcription) mRNA leaves nucleus and travels to ribosome Ribosome binds to mRNA Ribosomal binding site Searches for AUG start codon Finds the start codon and starts translating tRNA Has sequences complementary to mRNA tRNA sequences = anticodons mRNA sequences = codons Every 3 nucleotides = 1 codon Every 1 codon = codes for 1 amino acid tRNA has amino acids hanging off Get added to polypeptide chain when the codon for it is read When codon is read, tRNA binds complementary area Releases amino acid A site of Ribosome: Binds the tRNA’s that have amino acids on them 1st site P site: Binds the tRNA’s that are now bound to mRNA Haven’t let go of their amino acids yet E site: Releases amino acid from tRNA and joins it to peptide chain End: amino acid chain (polypeptide) AKA protein Final Exam Study Guide: Lecture 24: Gene Expression: Expression: creation of the final functional products (protein or RNA) Cell needs to control: How many times transcription happens At what rate it happens When it happens Recruiting RNA polymerase: Must be recruited to the start of region of DNA to begin transcription Promoter: the “start” where the polymerase is recruited Able to interact with polymerase Facilitates dissociation of double helix Something else must recruit it to the DNA
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General transcription factors do this recruiting General Transcription Factors: 1. Recognize specific sequence of DNA 2. Bind to the RNA polymerase Promoters: ^* know order Strength depends on its ability to produce transcript at a certain rate 3 classes: Constitutive: not regulated strongly, base state = “on” Strong constitutive : transcription relatively high Weak: transcription relatively low Activated/Induced: respond to a stimulus to increase transcription Base state is “off” Repressed : respond to stimulus to decrease transcription Base state is “on” Transcription factors: the proteins that act as this stimuli for gene regulation Bind specific DNA sequences (operatore) near the promoter Activator: increases transcription Repressor: decreases transcription Positive/Negative Regulation: For Transcription Factors: only look at what happens to transcription Represses transcription = negative regulator Gene expression could still be affected positively If it is removed, transcription continues Increases transcription = positive regulator If it is removed, transcription stops Allosteric Modulators of Regulatory Proteins: Stimulate the transcription factors AKA inducers, co-repressors, or co-activators
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