The surfaces of the cells that form the alveoli (small air spaces of the lung) are coated with surfactant, which decreases the alveolar surface tension. 

Lung surfactant contains 80 to 90% phospholipid by weight, and 70 to 80% of the phospholipid is phosphatidylcholine, mostly the dipalmitoyl species.

TLS Online TPP Program

#Id: 8098

#XL - T Zoology

The surfaces of the cells that form the alveoli (small air spaces of the lung) are coated with surfactant, which decreases the alveolar surface tension. 

Lung surfactant contains 80 to 90% phospholipid by weight, and 70 to 80% of the phospholipid is phosphatidylcholine, mostly the dipalmitoyl species.

TLS Online TPP Program

#Id: 7957

#XL - Q Biochemistry

Immediately after the entire precursor, Glc3Man9(GlcNAc)2 is transferred to a nascent polypeptide, three different enzymes, called  glycosidases, remove all three glucose residues and one particular mannose residue.

TLS Online TPP Program

#Id: 7956

#XL - Q Biochemistry

A branched oligosaccharide containing 

3 glucose (Glc)

9 mannose (Man)

2 N-acetylglucosamine (GlcNAc)

Glc3Man9(GlcNAc)2

TLS Online TPP Program

#Id: 7955

#XL - Q Biochemistry

Only asparagine residues in the tripeptide sequences Asn-X-Ser and Asn-X-Thr (where X is any amino acid except proline) are substrates for oligosaccharyl transferase.

TLS Online TPP Program

#Id: 7954

#XL - Q Biochemistry

The precursor oligosaccharide is transferred from a

dolichol lipid anchor to the asparagine as an intact unit in a reaction catalyzed by a transmembrane oligosaccharyl transferase enzyme complex.

TLS Online TPP Program

#Id: 7953

#XL - Q Biochemistry

Tunicamycin

blocks the first enzyme in this pathway, inhibits the synthesis of all N-linked oligosaccharides in cells.

TLS Online TPP Program

#Id: 7952

#XL - Q Biochemistry

Two N- acetylglucosamine (GlcNAc) and five mannose residues are added one at a time to a dolichol phosphate on the cytosolic face of the ER membrane