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17 Cards in this Set
- Front
- Back
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Importance of transcription
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- development (congenital defects)
- differentiation (stem cells) - activation (lymphocyte) - cell cycle (cancer) - microbes - biotechnology disruptions in transcription cause disease because it is central for gene expression |
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what is the difference between RNA polymerase and DNA polymerase?
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DNA polymerase: proteins that synthesize new DNA strands using preexisting DNA strands as templates. Requires a primer
RNA polymerase: synthesizes RNA from a DNA template. Does not require a primer. |
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What type of RNA do the three polymerases make?
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RNA I- rRNA
RNA II- mRNA RNA III- tRNA |
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How does tRNA work?
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It serves as an "adaptor" molecule that carries a specific amino acid to the site of protein synthesis. There it recognizes the genetic code word on mRNA, which specifies the addition of the amino acid to the growing peptide chain.
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How is mRNA modified?
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On the 3' end a long sequence of adenine nucleotides (poly-A-tail) is added. On the 5' end, a "cap"is placed.
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What is a promoter region?
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a nucleotide sequence at the beginning of a length of DNA that is to be transcribed.
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what is a transcription factor?
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Transcription factors are protein complexes that help RNA polymerase bind to DNA. By controlling RNA polymerase's access to the gene, transcription factors control the rate at which a gene is transcribed. Without transcription factors, cells would not be able to effectively regulate the rate at which genes are expressed.
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What is a TATA box?
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It is basically the binding site of RNA polymerase II. It's a short sequence of base pairs occurring in the promoter region 25 to 35 bases upstream from the transcriptional start site that binds the general transcription factor TFIID which begins the formation of the transcription initiation complex which includes RNA polymerase.
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Where are ribosomes synthesized?
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In the nucleolus via RNA polymerase I. The other RNAs are synthesized in the nucleoplasm.
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What is the popular inhibitor of RNA polymerase II?
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alpha- amantin
- a.k.a, the "death cap" it forms a tight complex with the polymerase to inhibit mRNA synthesis, thereby inhibiting protein synthesis. |
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which kind of RNA gets transcribed the most?
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rRNA (roughly 80%)
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Basic Transcription cycle:
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Initiation, elongation, termination.
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what is the importance of TATA binding protein?
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this protein recognizes the TATA sequence which allows TFs to bind to TATA.
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What are snRNA's and what is their role?
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small nuclear RNAs form small nuclear ribonucleoprotein particles that facilitate the splicing of exon segments
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What are the ingredients for protein synthesis?
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tRNA, mRNA strand, small and large ribosomal subunites
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What are the steps of translation?
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1. small ribosomal unit binds mRNA
2. the initiator tRNA attached to meth binds to the P site 3. large subunit joins, A site can receive another tRNA 4. another tRNA binds to the A site 5. peptidyl transferase transfers the amino acid from the P site to the amino acid at the A site. The tRNA that was at the P site moves over to the E site and the tRNA in the A site (now with growing peptide) moves over to the P site. 6. a new tRNA moves into the now vacant A site as the ribosome moves to the next codon. The peptide on the P site gets added to the amino acid on the tRNA in the A site. 7. Continues until a stop codon is hit. 8. Terminal signal complex docks at the A site and peptide is released. |
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What enzyme catalyzes the reaction of amino acid ond formation on a growing peptide being translated?
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peptidyl transferase
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