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TLS Online TPP Program

#Question id: 3982

The diagram below represents a hypothetical operon in the bacterium E. coli.  The operon consists of two structural genes (A and B) that code for the enzymes A-ase and B-ase, respectively, and also includes P (promoter) and O (operator) regions as shown.

 When a certain compound (X) is added to the growth medium of E. coli, the separate enzymes A-ase and B-ase are both synthesized at a 50-fold higher rate than in the absence of X (which has a molecular weight of about 200).  Which one of the following statements is true of such an operon?

#Unit 3. Fundamental Processes

  1. Adding X to the growth medium causes a repressor protein to be released from the O region.

  2. Adding X to the growth medium causes a repressor protein to bind tightly to the O region.

  3. Synthesis of the mRNA from this operon is not changed by the addition of compound X.

  4. The mRNA copied from this operon will be covalently linked to a short piece of DNA at the 5' end.

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TLS Online TPP Program

#Question id: 4949

#Unit 11. Evolution and Behavior

What probably accounts for the switch to DNA-based genetic systems during the evolution of life on Earth?
TLS Online TPP Program

#Question id: 33148

#Unit 2. Cellular Organization

Following components are belong to RING finger containing protein, except?
TLS Online TPP Program

#Question id: 26585

#Unit 3. Fundamental Processes

Due to its Structure of growing Telomere is potential target for
TLS Online TPP Program

#Question id: 10813

#Unit 6. System Physiology – Plant

A living cytoplasmic connection penetrate the walls between sieve tube elements and their companion cells; which are often complex and branched on the companion cell side, known as
TLS Online TPP Program

#Question id: 10925

#Unit 7. System Physiology – Animal

During the second trimester of pregnancy, where is the predominant site of red blood cell production?