BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The buildup of the glycan is initiated at the cytoplasmic leaflet of the ER membrane by the addition of N-acetylglucosamine (GlcNAc)-phosphate to dolichol-phosphate (Dol-P) from nucleotide-activated UDP-GlcNAc.

Detailed explanation-2: -N-linked glycosylation occurs co-translationally and is initiated in the endoplasmic reticulum (ER).

Detailed explanation-3: -There are two types of protein glycosylation, both of which require import of the target polypeptide into the ER. N-linked glycosylation actually begins in the endoplasmic reticulum, but O-linked glycosylation does not occur until the polypeptide has been transported into the Golgi apparatus.

Detailed explanation-4: -N-glycan processing is carried out in endoplasmic reticulum and the Golgi body. Initial trimming of the precursor molecule occurs in the ER and the subsequent processing occurs in the Golgi.

Detailed explanation-5: -The majority of proteins synthesized in the rough endoplasmic reticulum undergo glycosylation. Glycosylation is also present in the cytoplasm and nucleus as the O-GlcNAc modification. Aglycosylation is a feature of engineered antibodies to bypass glycosylation.