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32 Cards in this Set
- Front
- Back
DNA Transcription steps
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1. Binding of DNAp to promoter
2. Initiation of transcription 3. Elongation of transcription 4. Termination of transcription |
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Requirements for RNA synthesis
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1. a 2 stranded DNA template
2. DNA dependent RNAp 3. 4 nucleoside triphosphates 4. Mg |
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Holoenzyme
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A catalytically active enzyme with all its subunits
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RNAP 1
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#1 gives the large stuff
Forms the ribosome components 5.8s,28s, and 18s. |
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RNAP 2
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2 m's 1 s and gives the protein editors
Synthesizes precursors of mRNA, snRNA and miRNA |
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RNAP 3
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Forms the 5s rRNA and tRNA. Also has a signal recognition site and implicated in RNA splicing.
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Stages of RNA synthesis and what is the primer for the start sequence?
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Binding, initiation, elongation, and termination.
No need for a primer the start site is always a GGG or AAA. |
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DNA primer
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Short strand of RNA produced by primase.
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RNA promoter
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Promote the gold cone and Cat parties of RNA
GC(-110) and CAAT(-40) sequences are used to start RNA transcription in addition to the TATA box |
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Transcription stop signal
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A rapid folding in the newly synthesized RNA chain can cause this like an anchor dropping off a ship.
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Prokaryotic v Eukaryotic translation
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Prokaryotes can transcribe and translate at the same time because they don't have any introns and no need for mRNA modification.
Eukaryotes need post translational modifications like capping and introns splicing before they can translate. |
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hnRNA
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Unprocessed prescursor mRNA that is still in the nucleus.
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Transcription factors
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Controls the drafting of mRNA soldiers. TF3 give 5s rRNA. TF2D give TBP.
A protein that binds to a specific site in DNA and controls the transcription of information. TF 3 gives rise to 5s RNA. |
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Enhancer sequences
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They increase the rate of transcription and can be located far away from their site of action.
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Zinc finger protein
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A family of proteins that bind to DNA. Many TFs use this motif. Cys and His residues bind to Zn
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TATA box and starting protein translation
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Initiation begins with the recognition of this site by TBP(TATA binding protein)
TBP is part of TF2D |
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Poly A tail making signal
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AAUAAA on mRNA signals this addition.
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Introns and cleavage
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Introns all start with GU at the 5' end and and with AG at the 3' end. snRNPs recognize these cleavage sites and make up the Spliceosome. These are rich in uridine.
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Spliceosomal cleavage
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Recognizes the GU/AG sites and cleaves. Each end forms a 2'-5' phospodiester linkage loop at the branch site. The two exons are joined and the spliceosome releases.
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Lupus
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Antibodies to snRNPs block slicing of introns and proteins aren't formed.
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Constituitive enzymes
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Enzymes that are always present, they do the general housekeeping of the body.
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What is the normal concentration of Induced enzymes?
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Present in low amounts and then increase when needed
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Enzyme repression
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Enzymes not synthesized unless needed
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Ioerib
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Complete regulatory unit of a set cluster of genes, they include the structural components of the genes.
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Repressor genes
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The control units of genes. When substrates are bound here transcription is inhibited.
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Lac operon
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Produces lactose metabolites. Inhibited in the presence of glucose. Induced when allolactose binds to the repressor and allows transcription.
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Lactose proteins.
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Beta-galactosidase breaks down lactose into glucose and galactose. Permease is created and inserted into the cell membranes to allow lactose to pour into the cell. Once the lactose concentration is reduced enough, the repressor will be able to bind again to the lac operon and synthesis of these two proteins is inhibited.
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Alternative splicing
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The poly A tail can be added to different sites of the mRNA and that creates different versions of translational models.
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RNA editing
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Is like typing a different chemical onto RNA
Information in RNA is altered through a chemical change, This could be a Cyt to Val deamination. |
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What sequences of mRNA are unstable?
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AUUUA sequences are unstable and can lower the half life of mRNA
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miRNA
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Regulates mRNA soldiers the same way siRNA does.
Functional in gene regulation and medicinal purposes. Forms a partly double stranded RNAs with mRNA in order to inhibit or initiate processes. At the point of hybridization the miRNA puts on a target for Dicer that cleaves the mRNA. |
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siRNA
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Block and kills mRNA sequences
Silencing or interfering RNAs form a long double stranded RNA that inhibit the expression of genes by setting up sites that target mRNA for degradation |