Genetic Engineering Multiple Choice Questions on “Database Screening and Nucleic Acid Hybridisation – 1”.
1. The process of finding a particular member of the library which is having some defined properties is called as ___________
a) searching
b) screening
c) locating
d) narrowing
Answer: b
Explanation: The process of finding a particular member of the library which is having some defined properties is called as screening. Mostly screening is carried out for a particular coding sequence.
2. If for a particular organism sequence data is available and we have to simply search in the data through a computer, then this method is called as ___________
a) annotation
b) database search
c) in silico
d) electronic search
Answer: c
Explanation: The easiest way to find for a particular sequence is to exploit the genomic analyses. If the database is available for a particular sequence and the task is to simply search the data through the computer then the procedure is called in silico.
3. If we are having sequence data for a particular organism, but screening is carried out for homologues the program used is BLAST.
a) True
b) False
Answer: a
Explanation: Homologues are a group of organisms which contain similar sequences. Screening for such organisms can be carried out by using programs such as BLAST (Basic Local Alignment Search Tool). Search can be carried out within or for nucleotide and protein sequences.
4. If screening is carried out on the basis of sequences which are related to the desired sequence, then the process is called ___________
a) in-silico
b) homologue search
c) annotation
d) partial search
Answer: c
Explanation: If the search is carried out on the basis of the related sequence rather than looking for the actual sequence then the process is termed as an annotation.
5. How many techniques are there for carrying out the screening of sequences encoding for RNAs?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: There are basically two techniques used for carrying out the screening of sequences encoding for RNAs. The first technique is based on nucleic acid hybridization and the second is based on coding function in vivo.
6. Choose the incorrect statement for colony or plaque lift.
a) It is the base for screening based on nucleic acid hybridization
b) It is also known as Grunstein-Hogness technique
c) It is based on the fact that which members of the library have the same sequence as the DNA probe
d) The library may be plaques on a bacterial lawn and in that case it is known as plaque lift
Answer: c
Explanation: Colony lift or plaque lift is the basis for nucleic acid hybridization. It is also known as Grunstein-Hogness technique named after the discoverer. It is based on the fact that which members of the library are complementary to the sequence of DNA probe can be known. The library may be plaques on a bacterial lawn and in that case it is known as plaque lift. There may be colonies on a plate and in that case, it is known as colony lift.
7. The screening of libraries us carried out by nucleic acid hybridisation and constitutes of following steps:
i) Peeling of membranes carrying away bacterial cells with it
ii) Cells are lysed and denaturing of DNA is being carried out
iii) Hybridization with labelled DNA
iv) Placing the membrane onto plate containing recombinant cells
Choose the correct sequence in which the steps are carried out (starting to ending).
a) iv)-i)-ii)-iii)
b) iv)-ii)-i)-iii)
c) i)-ii)-iii)-iv)
d) iii)-ii)-i)-iv)