question_answer

Restriction endonucleases recognise palindromic nucleotide sequences in DNA and cut them. What are palindromes? Explain with example.

Or

Expand ELISA. On what principle is ELISA test based? Explain.

Answer:

Palindromes are groups of letters that form the same words when read in both directions, i.e. forward and backward. The palindromes in DNA are base pair sequences that are same when read forward (left to right) or backward (right to left) from a central axis of symmetry, e.g.

EcoRI cuts the DNA between bases G and A only in the given sequence.

Or

ELISA (Enzyme Linked Immuno Sorbent Assay) is based on the ability of antibodies to couple with enzymes to produce enzymatically active immunological conjugates after reacting with a chromogenic substrate. Thus, the test can detect the presence of antigens like proteins and glycoproteins and antibodies in the serum of a patient.