Need Help with GeneticsMicrobiology questions for a hw In pr

Need Help with Genetics/Microbiology questions for a hw!

In prokaryotes such as E.coli, the transcription of ribosomal RNA takes place from _____. a. DNA sequences that are scattered among the circular chromosome and each 16$, 23S, and 5S sequence having its own promoter. b. DNA sequences that are repeated many times and scattered among the circuit chromosome but having only one promoter for each 5^+, 16S, 23S, 5S - 3\'. c. a signal DNA sequence that codes for 5\' - 16S, 23S, 5S -3\' with only one promoter for the sequence. d. All the above possibilities are seen in the E coli genome. In prokaryotes the Shine-Dalgamo sequence _____ a. is a conserved sequence on the ribosome RNA of the small submit of the ribosome which is recognized by the antiparallel sequence on the ribosomal RNA of the small submit of the ribosome which is recognized by the antiparallel sequence on the small ribosomal subunit. c. is a conserved sequence on the ribosomal RNA of the small subunit of the ribosome which is recognized by the antiparallel sequence on the tRNA. d. is a conserved sequence on the messenger RNA which is recognized by the antiparallel sequence on the tRNA. A segment of a polypeptide chain is encoded by the DNA segment below. What is the template strand? (The last page of this exam contains a chart with the code) a. The strand labeled \'X\' b. The strand labeled \'Y\' During translation in prokaryotes, initiation includes _____ a. fMET-tRNA binding to the A-site on the ribosome. b. fMET-tRNA binding to the P-site on the ribosome. c. MET-tRNA binding to the A-site on the ribosome. d. MET-tRNA binding to the P-site on the ribosome.

Solution

Please find the answers below:

Part 28: Choice C (Unlike eukaryotic genome, the prokaryotic system comprises of a single promoter for the whole cistron which brings about transcription and hence translation. This reduces complexity in prokaryotic genome and also accounts for its smaller size)

Part 29: Choice B (The complementarity between the conserved sequence of mRNA and the small subunit of ribosome accounts for very high specificity between these two structures. Bio-chemical studies have shown that this specificity between the two sequences remains the rate limiting step for binding and initiation of translation.)

Part 30: Choice B (It can be ascertained from the amino acid sequence that the nucleotide sequence of codons for this polypeptide remains complementary to the strand Y. Thus, the lower strand or Y is the template or non-coding strand.)

Part 31: Choice B (The start codon always binds to the middle P-site of the ribosomal assembly as directed by fMET-tRNA. It is then transferred to the E site as the polypeptide chain grows)