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15 Cards in this Set
- Front
- Back
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What is a sense strand?
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The DNA on top...also known as the coding strand
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What is the antisense strand?
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The DNA on the bottom, also known as the template strand
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Can RNA polymerase recognize and correct errors?
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NO! But this has less of an impact because MANY copies are RNA are made, where as it's more important in DNA because only one copy is made there
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in DNA-directed RNA synthesis, which direction is RNA synthesized from the template?
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RNA is synthesized with a 3' to 5' DNA strand as the template, and it synthesizes 5' to 3',, therefore it really goes 3' to 5'
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Is a primer needed in RNA synthesis?
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no
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what enzyme is needed to initiate and carry out RNA synthesis
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RNA polymerase
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when rna is created, is it single stranded or double stranded?
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single stranded
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Is the RNA a copy of the whole dna strand or just part of it?
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part of it
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What is a promotor?
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a specific area on a piece of DNA that is recognizable by the RNA polymerase. this is where transcription begins
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explain how RNA transcription is initiated
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RNA polymerase combines with omega subunit to recognize the promotor site. Transcription is initiated. Topoisomerases are needed during transcription to prevent supercoiling
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Explain the elongation step
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RNA polymerase moves in the 5'to 3' direction. After about 10 units are added, the omega subunit dissociates
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Explain the termination step
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There are two types of termination. There is rho-directed and non-rho directed.
In non-rho directed, it basically terminated by the DNA sequence. In this case, the formation of complimentary bases into a hairpin formation, along with weak AA:UU bonds, the RNA:DNA hybrid dissociates |
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explain rho dependent termination
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the rho factor chases the RNA polymerase down the line. When it hits a hairpin, it stalls. the rho factor catches up and dissociates the RNA
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in Euk. cells, transcription is somewhat similar but much more complicated. What is each of the RNA polymerases responsible for?
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RNA I--> creates large ribsomal RNA
RNA II--> synthesizes mRNA RNA II--> synthesizes tRNA/small rRNA |
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The post transcription process is much more complicated as well. What are the three things that occur to terminate transcription in euk. cells?
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5' capping, 3' polyadenylation and splicing
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