TLS Online TPP Program

#Question id: 169


 An octapeptide composed of four repeating glycylalanyl units has:

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. one free amino group on an alanyl residue.

  2. one free amino group on an alanyl residue and one free carboxyl group on a glycyl residue.

  3. one free amino group on a glycyl residue and one free carboxyl group on an alanyl residue.

  4. two free amino and two free carboxyl groups.

More Questions
TLS Online TPP Program

#Question id: 3981

#Unit 3. Fundamental Processes

The diagram below represents a hypothetical operon in the bacterium E. coli.  The operon consists of two structural genes (A and B), which 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.  (X has a molecular weight of about 200.)  Which of the following statements is true of the operon decribed above?

TLS Online TPP Program

#Question id: 3982

#Unit 3. Fundamental Processes

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?

TLS Online TPP Program

#Question id: 3983

#Unit 3. Fundamental Processes

Transcription of the lactose operon in E. coli is stimulated by:

TLS Online TPP Program

#Question id: 3984

#Unit 3. Fundamental Processes

Which of the following statements about regulation of the lac operon is true?

TLS Online TPP Program

#Question id: 3985

#Unit 3. Fundamental Processes

The binding of CRP (cAMP receptor protein of E. coli) to DNA in the lac operon:

TLS Online TPP Program

#Question id: 3986

#Unit 3. Fundamental Processes

Consider the lac operon of E. coli.  When there is neither glucose nor lactose in the growth medium: