The trp operon in E. coil is regulated in such a manner as to allow expression o
ID: 176013 • Letter: T
Question
The trp operon in E. coil is regulated in such a manner as to allow expression of the genes only when cellular levels of tryptophan are low. When tryptophan levels are abundant the repressor of the trp operon is activated by binding tryptophan. This form of regulation is known as inducible negative regulation inducible positive regulation repressible negative control repressible positive control attenuation. A researcher is interested in the mode of transport across the cell membrane of the three different substance: A, B, and C. The graph are below shows the initial rate of transport for each substance, when the cells are placed in solutions of different concentrations of A, B, and C. Based on this data, substance A is transported via active transport. facilitated transport. passive transport. simple diffusion. choices A, B, and C The phase of the cell associated with the doubling of the amount of DNA in the cell is G0. B S. C G1. D G2. E M. The type of ATPases associated with the integral binding of ATP as part of the transport process and possessing a conserved domain for the binding of ATP is the ABC type. F type. P type. V type. You wish to rapidly dehydrate a animal tissue using salt solutions. The best concentration to use would 0.01%. 0.09%. 0.9%. 1%. 10%. Whether a molecule can cross the plasma membrane depends upon the size of the molecule the chemical proper ties of the molecule. the charge of the molecule. all of the above. none of the above The situation in which an active regulatory protein "turns off" expression is an example of positive control. negative control. constitutive gene elements. a mutation. unique regulation.Explanation / Answer
1. C repressible negative control,
Explanation :- Tryptophan is an example for the repressible negative control, when the tryptophan levels are low this operon is active and express to synthesize the tryptophan , where tryptophan is very essential aminoacid for many metabolic enzymes.When the tryptophan levels are high the monomeric repressor protein binds to the operator sequence and repress the operon and stop the expression.
2.B facilitated diffusion,
Explanation :- If the concentration of the solute increases which facilitates movement into the cell by the assistance of carrier proteins is called as facillitated diffusion..It obtains liner shaped graph when plotted.
3) B S phase
In S phase which is called as Synthesis phase, in which DNA amount is doubled due to replication and preparation of cell for division.
4) A ABC Type Domains.
Explanation :- ATP binding cassette type of ATPases which present in prokaryotes as transmembrane protein which facilitate the transport of moelcules,it utilises ATP for translocation.
5) E 10 % is used to dehydrate the animal tissue for about 24 hrs.
6) D all of the above, for the diffusion of molecule through plasma membrane it depends on the charge,size of molecule, chemical properties,shape of the molecule.
7) B Negative control , when the regulatory protein turn off the expression of operon.
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