Lipids and polysaccharides do not use a template to synthesize; they employ a series of biosynthetic processes with essential substrate and enzyme concentrations.
In contrast to proteins that have a template (messenger RNA) to direct its synthesis, polysaccharides do not use a template mechanism. Instead, each linkage made is catalyzed by an enzyme that recognizes the sugars it is linking. For example, polysaccharides are synthesized in a biosynthetic process called gluconeogenesis which generates glucose.
Likewise, lipids do not use a template to synthesize. The biosynthesis of fatty acids is regulated by the enzyme acetyl CoA carboxylase. In animals and fungi, all the fatty acid synthase reactions are carried out by a single multifunctional protein. At the same time, in plants and bacteria, separate enzymes perform each step in the pathway.
MCAT Official Prep (AAMC)
Practice Exam 4 B/B Section Passage 2 Question 7
Key Points
• Polysaccharides do not use a template mechanism. Instead, each linkage made is catalyzed by an enzyme that recognizes the sugars it is linking. They are synthesized using a pathway called gluconeogenesis. Likewise, lipids do not use a template to synthesize. The biosynthesis of fatty acids is regulated by the enzyme called acetyl CoA carboxylase.
Key Terms
biosynthesis: the production of complex molecules within living organisms or cells
acetyl-CoA carboxylase: an enzyme that catalyzes fatty acids
polysaccharide: is a large molecule made of many smaller sugars
gluconeogenesis: is a metabolic pathway that results in the generation of glucose
