Biotechnology chapter MCQs class 12




Choose the correct option

1. The bacterium which causes a plant disease called crown gall is ................
    a. Helicobacter pylori
    b. Agrobacterium tumifaciens
    c. Thermophilus aquaticus
    d. Bacillus thuringienesis

Answer : B
Explanation : Crown gallplant diseasecaused by the bacterium Agrobacterium tumefaciens (synonym Rhizobium radiobacter). 


2. The enzyme nuclease hydrolyses ............... of polynucleotide chain of DNA.
    a. hydrogen bonds
    b. phosphodiester bonds
    c. glycosidic bonds
    d. peptide bonds

Answer : phosphodiester bond 


3. In vitro amplification of DNA or RNA
segment is known as ...............
    a. chromatography
    b. southern blotting
    c. polymerase chain reaction
    d. gel electrophoresis

Answer : Polymarase chain reaction


4. Which of the following is the correct recognition sequence of restriction enzyme hind III.
   a. 5’ ---A-A-G-C-T-T---3’ 3’ --T-T-C-G-A-A--- 5’
   b. 5’ ---G-A-A-T-T-C---3’ 3’ ---C-T-T-A-A-G--- 5’
   c. 5’ ---C-G-A-T-T-C---3’ 3’ ---G-C-T-A-A-G--- 5’
   d. 5’ ---G-G-C-C---3’ 3’ ---C-C-G-G--- 5’

Answer : B


5. Recombinant protein .................. is used to dissolve blood clots present in the body.
    a. insulin
    b. tissue plasminogen activator
    c. relaxin
    d. erythropoietin

Answer : B
Explanation : Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. It is a serine protease (EC 3.4. ... tPA can be manufactured using recombinant biotechnology techniques; tPA produced by such means are referred to as recombinant tissue plasminogen activator (rtPA).


6. Recognition sequence of restriction enzymes are generally ............... nucleotide long.
    a. 2 to 4
    b. 4 to 8
    c. 8 to 10
    d. 14 to 18

Answer : B
Restriction endonucleases recognise specific palindromic sequences of 4–8 nucleotides in length. Short recognition sequences are likely to be more frequent in a genome than longer recognition sequences, which is why more fragments of lower molecular size are produced.

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