Tryptophan is an amino acid necessary for E. coli survival and growth. E. coli contain genes coding for enzymes that synthesize
tryptophan. These genes are grouped together on a segment of DNA called the tryptophan (trp) operon. Cells can use these enzymes to synthesize tryptophan when it is not present in the environment. owever, when tryptophan is already present in the environment, cellular resources are shifted away from manufacturing the enzymes for tryptophan synthesis. Tryptophan binds with and activates the trp repressor, which then binds to the trp promoter and blocks RNA polymerase. Blocking RNA polymerase decreases the normal transcription rate of the operon. What type of regulation does the trp operon exhibit?a. positive regulation b. protein modification c. negative regulation d. translational regulation
The correct answer is - The tryptophan operon shows C. negative regulation.
Explanation:
Tryptophan is an amino acid, excessively synthesized by the organism, it regulates its transcription through “trp Operon.” In this operon, the corepressor of the tryptophan binds to the repressor protein and gets activated.
This activated repressor now binds to the operator site, and prevents the binding of RNA polymerase enzyme and inhibits the protein synthesis.
Under extreme temperatures Enzymes become inactivated or denatured. due to this reason there will be no change in Photosynthesis despite a change in Light intensity.
aquaporins are channel proteins that allow water to flow through a membrane. The rate of osmosis depends on ratio of intracellular to extracellular concentration as well as the presence of aquaporins in the cell membrane
Label B - The outside layer of a plant cell is cell wall, in an animal cell it is the cell membrane. The label A is the Golgi Body(Complex). The inside label D is cytoplasm, and little dots labeled C are most probably lysosomes. Without seeing the picture it is hard to tell.
Pluripotent cells can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent. Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent.
