NEET2026BiologyChapterActual
Which of the following best describes the palindromic nucleotide sequences recognized by restriction endonucleases in DNA?
Options
- ASequences of base pairs that read the same on the two strands when the orientation of reading is kept differen
- BSequences where the purine content is exactly equal to the pyrimidine content on a single strand.
- CSequences of base pairs that read the same on the two strands when the orientation of reading is kept the same
- DSequences that direct the restriction enzyme to cut only one specific strand of the DNA double helix.
Correct answer
C. Sequences of base pairs that read the same on the two strands when the orientation of reading is kept the same
Step-by-step solution
A palindromic sequence in DNA is a sequence of base pairs that reads the same on the two strands when the orientation of reading is kept the same. For example, the sequence recognized by EcoRI is 5' -GAATTC- 3' on one strand and 3' -CTTAAG- 5' on the complementary strand. When both strands are read in the 5' 3' direction, the sequence is GAATTC. Restriction endonucleases recognize these specific palindromic nucleotide sequences and cut both strands of the DNA double helix. Answer: Sequences of base pairs that read