<span>Antibiotics work by selectively targeting the reproduction or growth of specific bacteria cells and by not attacking human DNA. Antibiotics do not, or should not, target and affect human DNA gyrases, although they should target the specific bacteria growth. The host, (human) DNA needs to remain unharmed while the bacteria does not replicate.</span>
Where can you find sandy soil?
I.Shorelines
II.Beach
III.Farm
IV. Rain forest
<u>A.I and III </u>
B.II and III
C. III and IV
D. I and IV
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.