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TLS Online TPP Program

#Question id: 3834

In his transformation experiments, what phenomenon did Griffith observe?

#Unit 3. Fundamental Processes

  1. Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

  2. Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.

  3. Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains.

  4. Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.

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TLS Online TPP Program

#Question id: 30103

#Unit 1. Molecules and their Interaction Relevant to Biology

Direct sources of purine ring atoms in the de novo synthesis of IMP include:
1. glutamine.
2. a component of the tetrahydrofolate one-carbon pool.
3. aspartate.
4. glycine.
TLS Online TPP Program

#Question id: 30104

#Unit 1. Molecules and their Interaction Relevant to Biology

A nucleoside phosphorylase:

1. cleaves a nucleoside with the production of ribose 1-phosphate.
2. is necessary for the major salvage pathway for pyrimidines.
3. is used in the degradation of purine nucleotides.
4. is responsible for the equilibration of nucleoside monophosphates and nucleoside diphosphate.
TLS Online TPP Program

#Question id: 30105

#Unit 1. Molecules and their Interaction Relevant to Biology

Methotrexate is an inhibitor of dihydrofolate reductase. Administration of methotrexate would inhibit:
1. de novo synthesis of UMP.
2. conversion of dUMP to dTMP.
3. conversion of IMP to GMP.
4. de novo synthesis of IMP
TLS Online TPP Program

#Question id: 30106

#Unit 1. Molecules and their Interaction Relevant to Biology

If a cell has an adequate supply of adenine nucleotides but requires more guanine nucleotides for protein synthesis:

1. Glutamine-PRPP amidotransferase will not be fully inhibited.
2. AMP will be a feedback inhibitor of the condensation of IMP with aspartate.
3. ATP will stimulate the production of GMP from IMP.
4. ATP will inhibit nucleoside diphosphate reductase.
TLS Online TPP Program

#Question id: 30107

#Unit 1. Molecules and their Interaction Relevant to Biology

Major controls of de novo AMP synthesis include:

1. allosteric inhibition by GMP.
2. allosteric inhibition by AMP.
3. availability of PRPP.
4. stimulation by GTP.
TLS Online TPP Program

#Question id: 30108

#Unit 1. Molecules and their Interaction Relevant to Biology

Aspartate plays a role in all of the following EXCEPT: