Question

Lipopolysaccharide is comprised of three moieties (lipid A, core oligosaccharide, and O-antigen), which require _____ biosynthetic pathway(s)?

1) one
2) two
3) three
4) six

Answer 1

The three components of lipopolysaccharide (lipid A, core oligosaccharide, and O-antigen) are synthesized separately and thus require three different biosynthetic pathways.

Step-by-step explanation:

The synthesis of lipopolysaccharide (LPS) is complex and involves multiple biosynthetic pathways due to its diverse components: lipid A, core oligosaccharide, and O-antigen. Lipid A is integrated into the bacterial outer membrane, the O-antigen varies among different bacterial species contributing to their diversity in immunogenicity, and the core oligosaccharide connects the lipid A to the O-antigen. These parts are synthesized separately and then assembled together, indicating multiple, not single, biosynthetic pathways.

Conclusion

The three moieties of the lipopolysaccharide require three separate biosynthetic pathways for their synthesis. Accordingly, the correct answer to the student's question is option 3) three