Practice Questions

TLS Online TPP Program

#Question id: 2888

Repressive complexes have been discovered that are composed of multiple repressing proteins bound to RNAs many kilobases in length that do not contain long open reading frames and are consequently called long noncoding RNAs or lncRNAs. Which of the following statements is correct regarding the regulation of these lncRNAs?

#Unit 2. Cellular Organization

X inactivation is controlled by a roughly 100-kb domain on the X chromosome called the X-inactivation center that encodes a lncRNA known as XIST that is responsible for inactivation of the maternally derived chromosome.
Depletion of a 2.2-kb noncoding RNA expressed from the HOXC locus by siRNA unexpectedly led to derepression of the HOXD locus, a roughly 40-kb region on another chromosome encoding several Hox proteins and multiple other noncoding RNAs, in these cells.
HOTTIP lncRNA, which is transcribed from the 5’end of the HOXA locus, is proposed to coordinate the activation of HOXA genes by binding to a histone H3 lysine 9 methylase represents the cis activation by lnc-RNAs.
In humans, but not in mice, a lncRNA called XACT has been discovered to associate with multiple sites along the full length of the active X chromosome and is postulated to contribute to repression of gene activity on that chromosome.

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TLS Online TPP Program

#Question id: 24489

#Unit 3. Fundamental Processes

Two transesterification reactions takes place for 2 exon -1 intron configuration. Choose the correct statement

a. First transesterification is always caused by exon 1 -3’OH

b. second transesterification is catalysed variably either by external G or branch point while .

c. First transesterification is catalysed variably either by external G or branch point while

d. second transesterification is always caused by exon 1 -3’OH.

TLS Online TPP Program

#Question id: 24490

#Unit 3. Fundamental Processes

There are three type of Splicing signals 1. Major U2-type or GU-AG introns 2. Minor U12-type or AU-AC introns & 3. Minor U12-type with GU-AG introns (hybrid type), which of the following is responsible for the recognition of branch point sequence UACUAAC?

TLS Online TPP Program

#Question id: 24491

#Unit 3. Fundamental Processes

There are three type of Splicing signals 1. Major U2-type or GU-AG introns 2. Minor U12-type or AU-AC introns & 3. Minor U12-type with GU-AG introns (hybrid type), which of the following is responsible for the recognition of branch point sequence CCUUAACU

TLS Online TPP Program

#Question id: 24492

#Unit 3. Fundamental Processes

Splice sites are directional in nature. 5’ splice site -the left, or donor, site and the 3’ splice site - right, or acceptor, site. So, in below table the complex and their events are given match them correctly .

TLS Online TPP Program

#Question id: 24493

#Unit 3. Fundamental Processes

Splice sites are directional in nature. 5’ splice site -the left, or donor, site and the 3’ splice site - right, or acceptor, site.

1. U2 addition to base pair with the branch site in the presence of ATP

2. U1 and U4 release Formation of the catalytic center in which U6 base pairs with the 5' splice site; U6 also base pairs with U2; U2 remains base paired with the branch site; U5 interacts with both exons through its loop.

So, 1 and 2 are the event of complex formation which are

TLS Online TPP Program

#Question id: 24494

#Unit 3. Fundamental Processes

U1 and U4 release Formation of the catalytic center in which U6 base pairs with the 5' splice site; U6 also base pairs with U2; U2 remains base paired with the branch site; U5 interacts with both exons through its loop is the characterstic of one of the stage during splicing, which is