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Which library should be used, genomic or cDNA when the screening is carried out by oligonucleotide probes?

A

Genomic

B

cDNA

C

Both genomic and cDNA library can be used equivalently

D

None of the libraries are preferred if oligonucleotide probes are used

Correct Answer: cDNA

If oligonucleotide probes are used, then cDNA libraries should be used. It is so because cDNA libraries are enriched for coding sequences and thus fewer sequences have to be screened.

cDNA made from the mRNA of an organism was used to make a cDNA library in a vector that allows the expression as a fusion with a reporter tag. What percentage of the cDNA clones is likely to give rise to correct gene products?

A

10%

B

30%

C

50%

D

100%

In order to isolate cDNA for a specified protein from a mice cDNA library prepared in λgt11 vector which of the following methods you will choose for screening?

A

Recombinational

B

Immunochemical

C

Polymerase chain reaction

D

Yeast two hybrid screen

cDNA libraries have been prepared that have the same sequences as the mRNA molecules produced by organisms, or else cDNA copies are sequenced directly by RT-PCR (copying of mRNA by reverse transcriptase followed by sequencing of the cDNA copy by the polymerase chain reaction).

A

True

B

False

Sometimes successive rounds of screening of a genomic library are carried out and an ordered collection of clones is done in a linear fashion, then the process is called as ___________

A

chromosome jumping

B

chromosome sorting

C

chromosome walking

D

transposon tagging

Jane, Karim and Leo checked out books from the library. Jane has an even number of library books . Karim has 3 more library books than Jane . Leo has 2 more library books than Karim. Which statement is true about the number of library books Karim and Leo have ?

A

Karim's number is odd, and Leo's number is odd.

B

Karim's number is odd, and Leo's number is even.

C

Karim's number is even, and Leo's number is odd.

D

Karim's number is even, and Leo's number is even.

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)

Mr. Bakhtiar works in the procurement department of a library. Under a new purchase policy, he increased the total number of books in the library by 20%. But soon afterwards, as part of the library cleaning process, 10% of the total library book stock is disposed of. What is the net change over the initial number of books in the library ?

A

increased of 10%

B

increased of 30%

C

decreased of 8%

D

none of these

A cell has five molecules of a rare mRNA. Each cell contains 4 × 10⁵ mRNA molecules. How many clones one will need to screen to have 99% probability of finding at least one recombinant cDNA of the rare mRNA, after making cDNA library from such cell?

A

4.50 × 10<sup>5</sup>

B

3.50 × 10<sup>5</sup>

C

4.20 × 10<sup>5</sup>

D

4.05 × 10<sup>5</sup>

Choose the correct statement if the screening is carried out by screening by expression in vivo.

A

The proportion of recombinants carrying gene of interest is small

B

The recombinants carrying gene of interest don’t complement the host mutation

C

Mutation should be affecting many genes

D

Most of the products selected would be result of complementation

In filter hybridization with oligonucleotide probes, the hybridization is performed _____ degrees below TM.

A

2

B

4

C

5

D

6