RNA POLYMERASE3. TRYPTOPHAN OPERON5. ORGANELLAR TRANSCRIPTIONBIO344 Quiz#5RNA POLYMERASEBriefly describe the functions of the following subunits of the E. Coli RNA polymerase.α-Interaction with upstream elements. β-Contains active site. Also binds DNA, RNA, and DNA/RNA hybridβ- Binds DNA, RNA, and DNA/RNA hybridσ-Promoter specificty2. LACTOSE OPERONThere are 2 types of regulation in Lactose operon. Please explain how they work.Negative regulationPositive regulation(Details in textbook)3. TRYPTOPHAN OPERONNotice that the trp operon codes genes for tryptophan synthesis and not breakdown as in the lactose and maltose pathway. This means that under high levels of tryptophan wesee repression of the synthetic genes. Another type of control that we see with this operon is attenuation. Please draw the two potential RNA conformations that can occurin the trp-leader RNA, labeling the 1,2,3, and 4 regions, the trp codons, and the stop codon. This should help to visualize the situation with attenuation.（details in textbook（4. REGULONWhat is a regulon and how is it different from an operon?Collection of genes not in the same operon that are co-regulated.Non contiguous, coordinately controlled genes.5. ORGANELLAR TRANSCRIPTION1).Answer the following questions in regards to the mitochondrial RNAP:a)how many subunits does it have? 1. phage-like polymeraseb)does it have a sigma factor?No, but it does have a specificity factorc)where does the specificity, i.e, promoter recognition come from and why might this be important?Specificity factor from nucleus, gives nuclear control of expression of mitochondrial genes2).Answer the following questions about chloroplast transcription.a) how many polymerases are found in a typical chloroplast?2Plastid-encoded polymeraseNuclear-encoded polymeraseb) plastids undergo extensive developmental changes in different types of plant cells. Please diagram the different types of plastids and their development. Light->Proplastid <-> Etioplast <->chloroplast <-> chromoplastb)Why it is important for chloroplast to have 2 different RNAPs?Provides for developmental regulationNEP is more important to proplasts (needed to make the rpo genes)PEP is more important in
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