Question

Only the proteins that the bacteria Escherichia coli (E. coli) needs are synthesized at any given time. For example, when lactose is available in the environment, E. coli will express the lac genes that allow it to break down lactose to obtain energy. When lactose is not present, these genes are not expressed.

This prevents the lac genes in the DNA of E. coli from being expressed most of the time.
A. the lac repressor
B. the lac operator
C. the lac promoter
D. the lac locator

Answer 1

The lac repressor prevents the lac genes in the DNA of E. coli from being expressed most of the time. The answer to your question is A. I hope this is the answer that you are looking for and it comes to your help.

Answer 2

The correct answer is A. Lac repressor.

Lac repressor prevents lac gene which are found in the DNA of Escherichia Coli from being expressed for many times.

Lac repressor is termed as DNA which binds proteins. It allows the expression of genes from coding which are made for proteins to be involved in metabolism of lactose which is in bacteria.

When there is no lactose which is available in the cell, then the genes are being repressed. Lactose are being converted to allolactose if they are available.