This set of Molecular Biology Multiple Choice Questions & Answers (MCQs) focuses on “Inverse PCR & Randomly Amplified Polymorphic DNA(RAPD)”.
1. The type of DNA amplification where the region of DNA amplified lies on either side of a known segment __________
a) RT – PCR
b) Anchored – PCR
c) Inverse – PCR
d) Nested – PCR
Explanation: PCR can be used to amplify the sequences flanking on either sides of a known DNA segment. The process uses primers complementary to the 5’ ends of the interested segment. This is a reverse process of the general PCR mechanism thus is known as the inverse PCR.
2. Primer complementary to regions used in inverse PCR is _____________
a) 3’ end of unknown region
b) 5’ end of unknown region
c) 3’ end of known region
d) 5’ end of known region
Explanation: Inverse PCR uses primers complementary to the 3’ ends of the known segment of DNA. this thus, amplifies the unknown regions on the either sides of the known region and thus is known as inverse PCR.
3. With respect to target DNA used in inverted PCR which of the following is not true?
a) Restricted segment
b) Blunt ended segment
c) Intact known segment
d) Flanked unknown segment flanked on either side
Explanation: The target DNA is cut with a restriction enzyme that produces sticky ends and that does not cut within the region of which the sequence is known. The cutter instead cuts at unknown sites on the either sides of the known sequence. This lets the DNA circularize later, which is a very important step for achieving our desired results.
4. The DNA concentration in inverse PCR is kept low _______
Explanation: The cut made by the restriction enzymes lie beyond the unknown region of our interest. As the restricted fragment thus produced has sticky ends it is left to circularize. The DNA taken for this process is in small quantity or else all the restricted fragments would bind among themselves and we will not get the desired circularized DNA.
5. The linear fragment used for inverted PCR has known ends _____________
Explanation: The molecular cutters used are rare and the cut producing the fragment involves the two regions of interest flanked to either sides of a known region. This fragment is left to circularize. This circular DNA is then restricted within the known DNA segment to produce a linear fragment having known ends on either sides.
6. With respect to RAPD which of the following is false?
a) 10 bases long
b) G/C rich
c) Has inverted repeats
d) Radom sequences are used
Explanation: RAPDs are generated by using random sequences of ordinarily 10 bases long oligonucleotides. These oligonucleotides are generally G + C rich and do not contain any repeated sequences.
7. Polymorphism in RAPD is observed because ______________
a) DNA used is from different chromosomes of same species
b) DNA used is from same chromosomes of same species
c) DNA used is from different chromosomes of different species
d) DNA used is from complementary chromosomes of same species
Explanation: In RAPD, primers for PCR amplification of genomic DNAs are from different species/strains. Thus polymorphism is produced due to the complementary sequence for the primer used being present in one strain and absent in another.
8. RAPDs cannot be used for PCR amplification.
Explanation: As the RAPDs behave as dominant markers, they are easily recognized by the primers for amplification. Thus, RAPDs turn out to be great templates for the primers for PCR amplification.
9. RAPDs are much more convenient markers than RFLPs .
Explanation: RAPDs have similar applications as RFLPs, but they are considerably faster and more convenient, particularly with such species where little previous work has been done. In some cases, RAPDs may generate such an amount of information in 4 weeks, which would have taken about 2 years to obtain using RFLPs.
10. The inheritance pattern of RAPD is _______________
Explanation: The inheritance pattern of RAPD is dominant type. The inheritance pattern of RFLP is Codominant type.
11. RAPDs can be used to detect multiple alleles of a marker.
Explanation: RAPDs can never be used to detect multiple alleles of a marker. Only RFLPs are able to detect multiple alleles of a marker within the samples of DNA.
Sanfoundry Global Education & Learning Series – Molecular Biology.
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