With respect to microRNAs, which, if any, of the following statements, is false?

a) A microRNA normally works by binding to perfectly complementary sequences within an RNA transcript, usually an mRNA.

b) Like the great majority of mRNAs an miRNA is usually produced as a larger precursor RNA that is capped and has a 3’ poly(A) tail.

c) The precursor miRNA undergoes different types of post-transcriptional cleavage by endoribonucleases that are specific for double-stranded target sequences.

d) A nuclear endoribonuclease called dicer cleaves the miRNA precursor so that it forms a stem-loop RNA.

TLS Online TPP Program

#Question id: 28695

#Unit 2. Cellular Organization

O-linked oligosaccharides is representing the attachment of glycoproteins to the hydroxyl (–OH) group in which amino acid residue?

TLS Online TPP Program

#Question id: 28696

#Unit 2. Cellular Organization

N-linked oligosaccharide is attaching carbohydrate chain to the amide nitrogen of which amino acid residue?

TLS Online TPP Program

#Question id: 28697

#Unit 2. Cellular Organization

Biosynthesis of all N-linked oligosaccharides begins in the rough ER with a preformed branched oligosaccharide precursor containing_____

i) Glucose (Glc)

ii) Galactose

iii) Mannose (Man)

iv) N-acetylglucosamine (GlcNAc)

v) N-acetylgalactosamine (GalNAc)

TLS Online TPP Program

#Question id: 28698

#Unit 2. Cellular Organization

the oligosaccharide precursor is assembled on a membrane- attached anchor called dolichol phosphate, which is___

TLS Online TPP Program

#Question id: 28699

#Unit 2. Cellular Organization

First sugar residue is attached to dolichol by ___

TLS Online TPP Program

#Question id: 28700

#Unit 2. Cellular Organization

Biosynthesis of all N-linked oligosaccharides begins in the rough ER with a preformed branched oligosaccharide precursor Glc3Man9(GlcNAc)2, Which of the following statements is incorrect about these biosynthesis?

a) the oligosaccharide precursor is assembled on a membrane- attached anchor called dolichol phosphate

b) First sugar residue is attached to dolichol by a glycosidic bonds & the other

sugars are added by high-energy pyrophosphate

c) Two N- acetylglucosamine (GlcNAc) and five mannose residues are added one at a time to a dolichol phosphate on the lumen

d) Four mannose and three glucose  residue are added one to a dolichol phosphate on the luminal side