MCQs on Applications
1 - Question
Which of the following is useful in applications of PCR?
a) It is manual
b) Only one sample’s analysis can be carried out at a time
c) It is having a high speed
d) The amount of DNA required initially is high
Explanation: PCR is having numerous advantages over normal cloning procedures. It is automated and many samples can be analysed at a time simultaneously. It is having a high speed and the initial amount of DNA required is very less.
2 - Question
What is the correct statement with respect to ddNTPs?
a) They are dideoxynucleotide triphosphates
b) They are used in the termination of DNA sequencing
c) They are used for initiating DNA sequencing
d) They are used in the case if the starting amounts are large
Explanation: ddNTPs are dideoxynucleoside triphosphates. It is used in the case for termination of sequencing. It is so because, both the hydroxyl molecules are removed sequencing would be terminated. It is beneficial in the case if the initial amounts are less.
3 - Question
Cycle sequencing is the DNA sequencing where very less amounts of template are utilised for carrying out the sequencing.
Explanation: Cycle sequencing is that when very less amounts of DNA template is used for carrying out the sequencing. And the whole process is facilitated by the use of ddNTPs.
4 - Question
Sickle cell anaemia is a genetic disorder. Which of the following doesn’t holds true for it?
a) It can be analysed by PCR
b) It destroys a restriction site
c) The mutation is in alpha globulin gene
d) The conventional approach took weeks for the whole analyses to be carried out
Explanation: Sickle cell anaemia is a mutation in the beta globulin gene. It destroys a restriction site and the analyses can be carried out by PCR. PCR is very fast in comparison to conventional methods which took weeks to be completed. And the former method is completed in just one day.
5 - Question
PCR products can be analysed in many ways. Which of the following is not possible?
a) Use of restriction enzymes
b) Determining whether a particular oliginucleotide probe hybridizes to a PCR product
d) Direct sequencing can’t be carried out
Explanation: Restriction enzymes can be used and analyses can be done via destroying the restriction site. Checking for the hybridization of oligonucleotide probe with a PCR product. Electrophoresis can be used to check the mobility and compare it with a wild type molecule. Direct sequencing can also be carried out in order to analyse the PCR product.
6 - Question
Which of the statements don’t hold true for the forensics and the amplification carried out?
a) In the case of forensics, conventional methods such as southern blotting are used very effectively
b) In cases of bone fragments which contain less than 300 nucleotides conventional methods can’t be applied as they involve southern blotting, restriction digestion etc
c) The poor condition of DNA also makes the PCR amplification difficult
d) Microsatellites composed of simply varying repeats of CA sequences are used
Explanation: In the case of forensics conventional methods are not very useful. If the bone fragments are having less than 300 nucleotides then the conventional methods can’t be applied easily.
7 - Question
The genetic relatedness between organisms can be identified by studying the band patterns when different PCR products are analysed electrophoreically. This method is called as ____________
a) restriction fragment length polymorphism (RFLP)
b) amplified fragment length polymorphism (AFLP)
c) random amplification of polymorphic DNA (RAPD)
Explanation: The genetic relatedness between organisms can be identified by studying the band patterns of different PCR products. This process is termed as random amplification of polymorphic DNA (RAPD).
8 - Question
PCR is useful in population genetics because at times it can be used to study genetics of bacteria that can’t be cultured axenically.
Explanation: If properly designed primers are used then it is possible to amplify DNA from one organism that can’t be separated from others. For say a bacterial strain in a mixed population.
9 - Question
PCR amplification can be used for which type of samples?
a) Old samples only
b) Recent samples only
c) Equally to both recent and old samples
d) Recent samples are preferred but can be applied to old samples also
Explanation: PCR amplification can be used equally to both recent and old samples. DNA from museum samples and archaeological sites is also used for amplification.
10 - Question
What is the problem associated with historical DNA samples?
a) They are less in amount thus amplification is difficult
b) Because the samples are very old, there can be contamination
c) They degrade during repeated cooling and heating cycles
d) As the samples are old, the standard sequences for comparison is not present
Explanation: The historical DNA samples though can be analysed but the main problem with them is that the duration for which they can be used. As the samples are very old they are often contaminated by bacteria.