Question

Which of the following statements is TRUE?

1. E. coli sigma factors all recognize one E. coli gene
2. Prokaryotic mRNAs contain sequences for sigma factor binding
3. mRNA in both E. coli and humans are translated with the same translation machinery
4. E. coli sigma factors all bind to the core RNA polymerase
5. mRNA always contains the nucleotide sequence encoding just one protein

Answer 1

Answer -A.

in this question given statement are false because in the e. coli or Prokaryotes more than one sigma factors are found that bound to different nucleotides sequence in different gene in different conditions.

For example sigma 70 for house keeping gene, sigma 32 for heat shock protein, sigma and 54 gene for nitrogen metabolism etc.

Answer- B

these statement are true . Because each sigma factor bind to specific cosensus nucleotide sequence that occurs in Prokaryotic mRNA .

For example sigma 70 bind to in -35 region TTGACA and -10 region TATAAT sequence while the sigma 24 bind to in -35 region GAACTT and -10 region TCTGA.

Answer-C

these statement are false because eukaryotic transcription us more complex process it use mor transcriptional machinary . So the eukaryotic transcription are totally different because it use maximum number of transcriptional factor and other protein.

Answer - D

these statement are true because all sigma factor bind with core subunit after the binding of core hole enzyme are called holoenzyme that are active polymares. In which sigma is responsible for specificity of gene while the core subunit are responsible for polymarization.

Answer -E

these statement are false because always mRNA encodes single polypeptide chain . Only in Prokaryotes one mRNA encodes single polyprotein after the cleavage these protein work. But in eukaryotes single mrna encodes more than one protein.