Which of the following best describes the biological role of the lac operon? a) it prevents other sugars from being metabolized until all available lactose has been used. b) it ensures that a cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment. c) it ensures that a cell produces enzymes involved in lactose metabolism in a constitutive manner. d) it ensures that bacterial cells produce lactose only when no other food sources are available.

B

Explanation:

The biological role of the lac operon is that it ensures that a cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment.

The lac operon coordinate the transport and metabolism of lactose in Escherichia coli and other bacteria.

The lacZ gene encodes beta-galactosidase, the enzyme that hyrolyzes lactose to galactose and glucose.

The lacY gene is responsible for the production of permease which transport lactose and galactose into the cell.

The lacA gene codes for thiogalactoside transacetylase.

there are mainly three domains in biological classification namely; archaea, bacteria, and eukarya.

archaea includes all the prokaryotic cells which are characterized by their lipid membranes. they have branched hydrocarbon which is attached to glycerol through an ether linkage.

bacteria includes all the prokaryotic cells, the cell membrane of which are made up of the unbranched fatty acid chain. in addition, they are attached to glycerol through an ester bond.

eukarya includes all the eukaryotic cells, that is, the cells contain a nucleus and other membrane-bound cell organelles.

they can be autotrophic as well as heterotrophic, unicellular as well as multicellular

they include kingdoms like protista, plantae, animalia, fungi et cetera.

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