Question

VOLJNO Lactose-fermenting bacteria metabolize lactose using two proteins, one binds external lactose and transports it into the cell, the other breaks down the lactose that comes into the cell. The two proteins are coded for by two genes that are under the control of a single promoter. You carry out a lactose fermentation test on an unknown bacterium and find that the result is positive. All of the following are applicable to this bacterium growing in the lactose broth, EXCEPT: A. An operon specific to lactose metabolism is being expressed. B. The proteins involved in lactose metabolism represent part of the bacterium's transcriptome. C. The fact that the bacterium possesses the genes for lactose metabolism means that they are part of its genome. D. A sigma factor would have been involved in initiating expression of the lactose! metabolizing genes. OE. The lactose metabolism genes would likely have been expressed as part of a polycistronic message (ie, transcript).

Answer 1

B, the proteins involved in lactose metabolism represent part of bacteria s transcriptome is incorrect

Because the proteins involved are collectively called as proteome. Transcriptome is the term that indicates the mRNA transcripts after transcription process.

The other options are correct because,

When lactose is present, the operons for lactose metabolism is expressed which results in mRNA transcripts that codes for proteins required for lactose metabolism-fermentation.

Bacteria use the genes in their genome to perform all its functions.

Sigma factor can influence gene expression by controlling transcription of mRNA.

Since two genes are controlled by a single promoter, the mRNA is said to be polycistronic. Most of the prokaryotes have polycistronic mRNA.