Which of the following are correct with reference to rDNA technology?
(A) Exo-nuclease removes nucleotides from the ends of DNA
(B) Replication starts at ori
(C) High velocity microparticle of gold, coated with DNA, are used to transfer DNA in animal a method known as gene gun
(D) Endo-nuclease makes cut at specific positions within DNA
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A), (B) and (D) only
(A) Exo-nuclease removes nucleotides from the ends of DNA — Correct. ‘Exo’ means outside: exonucleases cut nucleotides off the ends.
(B) Replication starts at ori — Correct. The origin of replication is the sequence where copying begins, and it also controls the copy number.
(C) High velocity microparticle of gold, coated with DNA, are used to transfer DNA in animal a method known as gene gun — Incorrect. Biolistics (gene gun) is the method suitable for plants; DNA is put into animal cells by micro-injection.
(D) Endo-nuclease makes cut at specific positions within DNA — Correct. ‘Endo’ means inside: endonucleases, such as restriction enzymes, cut within the DNA.
NCERT Extract:
Restriction Enzymes – …
