Download App

MODEL PAPER 1 — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYMODEL PAPER 14 Marks
Question
i. Explain how to find whether an E.coli bacterium has transformed or not when a recombinant DNA bearing ampicillin resistant gene is transferred into it.
ii. What does the ampicillin resistant gene act as in the above case?
✓

Answer

i. When an E.coli bacterium is transformed with a recombinant DNA bearing ampicillin-resistant gene in its plasmid, the recombinant plasmid will lose tetracycline resistance due to the insertion of foreign DNA but can still be selected out from non-recombinant ones by plating the transformants on ampicillin containing a medium. The transformants growing on ampicillin containing medium are then transferred to a medium containing tetracycline. The recombinants will grow on ampicillin containing medium but not one that containing tetracycline. But non-recombinant will grow on the medium containing both the antibiotics.
ii. In this case, one antibiotic gene helps in selecting the transformants whereas the other antibiotic resistance gene gets inactivated due to the insertion of alien DNA and helps in the selection of recombinants. Ampicillin resistant gene in the above case helps in selecting the transformants and act as a selectable marker.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "4 Marks Questions" from MODEL PAPER 1→MODEL PAPER 1 — all question types→BIOLOGY STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

How is sex determined in human beings?
→
Answer the following questions:
State and explain the law of segregation as proposed by Mendel in a monohybrid cross.
→
State the modifications of forelimb in animals as an example of homology.
→
  1. How does a chromosomal disorder differ from a Mendelian disorder?
  2. Name any two chromosomal aberration associated disorders.
  3. List the characteristics of the disorders mentioned above that help in their diagnosis.
→
Give a genetic explanation for the following cross. When a tall pea plant with round seeds was crossed with a dwarf pea plant with wrinkled seeds then all the individual of F1-population were tall with round seeds. However selfing among F1-population led to a 9:3:3:1 phenotypic ratio.
→
During her tour to a renowned forest, Sakshi saw a highway being constructed, which passes through the middle of the forest. She was unhappy seeing that and on return, she contacted the local eco-club and approached the concerned department to stop the work.
  1. What would be the effect on biodiversity, if the highway is constructed?
  2. How forests are useful to mankind?
  3. What values of Sakshi reflect here?
→
  1. How is amensalism different from parasitism and competition? Give an example for each.
  2. Define predation.
→
  1. Name the nuclei that fuse to form PEN.
  2. What is the ploidy of PEN?
  3. Explain the development of endosperm from PEN?
→
  1. Explain the phenomenon of multiple allelism and co-dominance taking ABO blood group as an example,
  2. What is the phenotype of the following:
  1. IAi
  2. ii
→
When and how does placenta develop in human female?
→