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TLS Online TPP Program

#Question id: 3640

Which of the following is true for the mechanism of excision repair?

#Environmental Science

  1. Endonuclease cleavage removes a portion of the damaged strand.

  2. The gap is filled in by DNA polymerase I

  3. The sugar-phosphate backbone is resealed by DNA ligase.

  4. All of the above are correct.

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TLS Online TPP Program

#Question id: 39290

#Plant Biotechnology

Q. Assertion: Protoplast fusion between CMS B. napus (with radish cytoplasm) and normal B. napus can produce healthy male sterile plants. 
Reason: The resulting cybrids can retain the radish mitochondria (for CMS) while replacing the radish chloroplasts with B. napus chloroplasts.
TLS Online TPP Program

#Question id: 39291

#Plant Biotechnology

Q. Assertion: In plant breeding, cytoplasm transfer via somatic hybridization is significantly faster than conventional backcrossing. 
Reason: Protoplast fusion can achieve in one year what typically takes 5–6 years through the backcrossing method.
TLS Online TPP Program

#Question id: 39292

#Plant Biotechnology

Q. Assertion: Symmetric hybrids allow for the transfer of genes between species that are sexually incompatible. 
Reason: Somatic hybridization bypasses the requirements of pollination and fertilization, enabling fusion between even completely sterile lines like monoploids.
TLS Online TPP Program

#Question id: 39293

#Plant Biotechnology

Q. Assertion: Cybridization enables the creation of unique organelle combinations that cannot be produced through sexual reproduction. 
Reason: Somatic fusion allows the mitochondria of one species to be combined with the chloroplasts of another, often resulting in recombinant organellar genomes. 
TLS Online TPP Program

#Question id: 39294

#Plant Biotechnology

Q. Assertion: Somatic hybridization is currently the primary method used for the commercial improvement of all major cereal and pulse crops. 
Reason: Techniques for protoplast isolation, culture, and fusion are not yet readily available for many important cereals and pulses.
TLS Online TPP Program

#Question id: 39295

#Plant Biotechnology

Q. Assertion: Chromosome elimination in somatic hybrids is a highly predictable process used for precise gene mapping. 
Reason: Genetic instability is a common limitation in somatic hybrids, particularly in wide interfamilial crosses, often resulting in abnormal or sterile plants.