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TLS Online TPP Program

#Question id: 4943

In what way were conditions on the early Earth of more than 3 billion years ago different from those on todayʹs Earth?

#XL - T Zoology

  1. only early Earth had water vapor in its atmosphere.

  2. Only early Earth was intensely bombarded by large space debris.

  3. Only early Earth had an oxidizing atmosphere.

  4. Less ultraviolet radiation penetrated Earthʹs early atmosphere.

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TLS Online TPP Program

#Question id: 5240

#XL - T Zoology

If bacteria grow in the presence of a large amount of DNase, which of the following recombination process completely inhibited?
TLS Online TPP Program

#Question id: 5241

#XL - S Microbiology

Genes a, b, and c are widely spaced in the bacterial genome. Transducing phage from an a+ b+ c+ bacterium were used to infect a culture of a- b- c- cells, and b+ transductants were selected. Which of the following best describes the predicted genotypes of these transductants?
TLS Online TPP Program

#Question id: 5241

#XL - T Zoology

Genes a, b, and c are widely spaced in the bacterial genome. Transducing phage from an a+ b+ c+ bacterium were used to infect a culture of a- b- c- cells, and b+ transductants were selected. Which of the following best describes the predicted genotypes of these transductants?
TLS Online TPP Program

#Question id: 5242

#XL - S Microbiology

Auxotrohic bacteria plating on different medium, it is observed that colonies grow on minimal plus threonine only, no colony on minimal plus leucine and no colonies grow on minimal medium cystein only. What are the actual genotypes of auxotroph?
TLS Online TPP Program

#Question id: 5242

#XL - T Zoology

Auxotrohic bacteria plating on different medium, it is observed that colonies grow on minimal plus threonine only, no colony on minimal plus leucine and no colonies grow on minimal medium cystein only. What are the actual genotypes of auxotroph?
TLS Online TPP Program

#Question id: 5243

#XL - S Microbiology

Auxotroph culture (His- and Lac-) culture of E. coli was mutagenised. On what media would one spread the mutagenised cells to select prototroph for both His+  and Lac+ cells?