NEET · Biology · STD 12 - 9. biotechnology principlas and process

The blue and white selectable markers have been developed which differentiate recombinant colonies from non-recombinant colonies on the basis of their ability to produce colour in the presence of a chromogenic substrate.

Given below are two statements about this method:
Statement I : The blue coloured colonies have DNA insert in the plasmid and they are identified as recombinant colonies.

Statement II : The colonies without blue colour have DNA insert in the plasmid and are identified as recombinant colonies.

In the light of the above statements, choose the most appropriate answer from the options given below:

A Both Statement I and Statement II are correct
B Both Statement I and Statement II are incorrect
C Statement I is correct but Statement II is incorrect
D Statement I is incorrect but Statement II is correct

Verified Solution

Answer & Solution

Correct Answer

(D) Statement I is incorrect but Statement II is correct

Step-by-step Solution

Detailed explanation

Statement I is incorrect but statement II is correct as a recombinant DNA is inserted within the coding sequence of an enzyme, \(\beta\)-galactosidase. This results into inactivation of the gene for synthesis of this enzyme. Thus, presence of insert results into insertional inactivation of the \(\beta\)-galactosidase gene and the colonies do not produce any colour and identified as recombinant colonies. Whereas non-recombinant transformants will produce blue colour in presence of chromogenic substrate.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match the terms in column \(I\) with their description in column \(II\) and choose the correct option.

Column \(-I\)	Column \(-II\)
\((A)\) Dominance	\((i)\) Many genesgovern a single character
\((B)\) Codominance	\((ii)\) In a heterozygousorganism only one allele expresses itself
\((C)\) Pleiotropy	\((iii)\) In a heterozygousorganism both alleles express themselves fully
\((D)\) Polygenic	\((iv)\) A single gene inheritanceinfluences many characters

NEET 2016 Medium

Match the items given in Column \(I\) with those in Column \(II\) and select the correct option given below:

Column-\(I\)	Column-\(II\)
\((a)\) Tricuspid valve	\((i)\) Between left atrium and left ventricle
\((b)\) Bicuspid valve	\((ii)\) Between right ventricle and pulmonary artery
\((c)\) Semilunar valve	\((iii)\) Between right atrium and right ventricle

NEET 2018 Medium

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