TLS Online TPP Program

#Question id: 15478


Escherichia coli preferentially utilizes glucose by preventing the uptake of lactose and switching off transcription of the lac operon. This mechanism is known as 

#SCPH05 I Biotechnology
  1. Inducible inhibition
  2. Carbon catabolite repression
  3. Feedback repression
  4. Substrate limitation
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TLS Online TPP Program

#Question id: 15817

#SCPH01 Biochemistry

You and your lab partner have isolated 20 new mutant yeast strains that are defective in synthesis of threonine, an amino acid. These Thr- mutants do not grow on minimal medium, but they do grow on minimal medium supplemented with threonine. Ten of your Thr- mutants (numbered 1 through 10) were isolated in a strain of mating type a (MAT a). The other 10 Thrmutants (numbered 11 through 20) were isolated in a strain of mating type α (MAT α). You and your lab partner cross each of the MAT a strains to each of the MAT α strains, and you include crosses to the appropriate wild-type strains. Your experimental observations are shown in the table below, where (-) indicates diploids that did not grow on minimal medium and (+) indicates diploids that did grow on minimal medium

Based on these experiments, what is the minimum number of genes required for threonine synthesis?

TLS Online TPP Program

#Question id: 19222

#SCPH28 | Zoology

Selectable marker, which will eventually be used to detect the presence of the T-DNA inserted into the plant chromosomal DNA, is usually placed next to the

TLS Online TPP Program

#Question id: 13076

#SCPH05 I Biotechnology

Restriction fragment length polymorphism denotes that a single restriction enzyme produces fragments of different lengths from the same stretch of genomic DNA of different strains of a species or from different related species. RFLPs are detected as follows:

i.  Large molecular weight genomic DNA is isolated from several strains or related species;

ii.  The fragments in these digests are separated through electrophoresis

iii.  These 'DNAs are then digested with a selected restriction enzyme

iv.  Exposed to a suitably radio-labelled appropriate DNA probe under conditions favouring DNA: DNA hybridization

v.  The resulting gel lanes are transferred and fixed to a suitable solid support and

vi.   The free probes are removed

vii.  The fragments to which the probe has hybridized are detected by filming them as distinct bands on a suitable photofilm through autoradiography.

TLS Online TPP Program

#Question id: 15233

#SCPH28 | Zoology

Low-percentage acrylamide gels are also used to separate
A) Large DNA
B) Large proteins
C) Large RNA
D) All DNA, Proteins, RNA

TLS Online TPP Program

#Question id: 20846

#SCPH28 | Zoology

Nitrate is energetically the best electron acceptor under anoxic conditions and is generally used preferentially by which type of microbes?