Solved Examples on Biotechnology

Question1: Gene synthesis is related to [CPMT 1991; RPMT 1996]

(a) V. Baer  

(b) H.G. Khorana 

(c) L. Pasteur         

(d) C. Linnaeus

Answer: b

Explanation: Har Gobind Khorana was an Indian-American biochemist who shared the 1968 Nobel Prize for Physiology or Medicine with Marshall W. Nirenberg and Robert W. Holley. Their research helped to show how the order of nucleotides in nucleic acids, which carry the genetic code of the cell, control the cell’s synthesis of proteins.

Question2: Which of the following enzyme is used to join DNA fragments? [CPMT 2003]

(a) Terminase       

(b) Endonuclease

(c) Lygase   

(d) DNA polymerase

Answer: c

Explanation: DNA ligase facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.

Question3: Chemical knives/molecular scissors of DNA are [CBSE PMT 1998, 2001; KCET 2000; Wardha 2001]

(a) Endonucleases          

(b) Polymerases  

(c) Ligases  

(d) Trascriptases

Answer: a

Explanation: Endonucleases cleaves the phosphodiester bond within a polynucleotide chain. Hence are known as chemical knives/molecular scissors of DNA.