Mutation of either the 5′ or the 3′ invariant splice-site bases at the ends of the intron resulted in pre-mRNAs that were bound by snRNPs to form spliceosomes; however, RNA splicing was blocked, and the pre-mRNA was retained in the nucleus. 

In contrast, mutation of both the 5′ and 3′ splice sites in the same pre-mRNA resulted in export of the unspliced pre-mRNA, although less efficiently than for the spliced mRNA, probably because of the absence of an exon-junction complex. When both splice sites were mutated, the pre-mRNAs were not efficiently bound by snRNPs, and consequently, their

export was not blocked.

TLS Online TPP Program

#Id: 7862

#Unit 1. Molecules and their Interaction Relevant to Biology

Which is not reducing sugar

Saccharides That Lack A Hemiacetal Are Not Reducing Sugars

Mono and di-saccharides which lack a hemiacetal

Polysaccharides where the ratio of hemiacetals to acetal linkages is very low

TLS Online TPP Program

#Id: 10495

#Unit 4. Cell Communication and Cell Signaling

Apoptosis 

genetically regulated process

Cell destroys itself (programmed cell death)

marked by the breakdown of cell components

TLS Online TPP Program

#Id: 6790

#Unit 3. Fundamental Processes

The miRNAs used in RNAi are produced as large RNA primary transcripts called pri-miRNA that are self-complementary and can automatically fold into a double-strand hairpin structure.

TLS Online TPP Program

#Id: 9350

#Unit 4. Cell Communication and Cell Signaling

RI and RII receptors are homodimeric proteins with serine/threonine kinases in their cytosolic domains. 

(RI and RII sufficient to serve as a functional hetero-tetrameric TGF-β receptor)

TLS Online TPP Program

#Id: 2372

#Unit 5. Developmental Biology

 In planarian regeneration, an anterior polarity is dependent on repression of Wnt signaling, & allows head formation.