Polysaccharides include which of the following?

Polysaccharides are complex carbohydrates made up of long chains of monosaccharide units bound together by glycosidic bonds. They serve various structural and energy storage roles in living organisms.

In this case, dextran and agar are both examples of polysaccharides. Dextran is a polysaccharide made from glucose and is used in various medical and scientific applications, including as a blood plasma volume expander and in microbiological media. Agar, derived from red algae, is also a polysaccharide that serves as a gelatinous medium for culturing microorganisms in laboratory settings. Both are significant in various biological and industrial processes.

The other options consist of substances that do not fall under the category of polysaccharides. Sterols and triglycerides are lipids, not carbohydrates. Proteins and nucleic acids are made up of amino acids and nucleotides, respectively, which are entirely different biochemical molecules. Fatty acids and glycerol are components of lipids, specifically fats, and oils. Understanding the classification of biomolecules is essential in microbiology, as it relates to the structure and function of various cellular components and their roles in metabolism.