Which of the following is not a heteropolysaccharide?
**Core Concept**
Heteropolysaccharides are complex carbohydrates composed of different monosaccharide units linked together by glycosidic bonds. They play crucial roles in various biological processes, including cell signaling, cell adhesion, and immune responses.
**Why the Correct Answer is Right**
Glycoproteins are not heteropolysaccharides, but rather conjugated proteins that contain carbohydrate chains (glycans) attached to a protein core. These glycans can be composed of various monosaccharides, but the protein component distinguishes glycoproteins from heteropolysaccharides.
**Why Each Wrong Option is Incorrect**
**Option A:** Glycosaminoglycans (GAGs) are indeed heteropolysaccharides, as they are composed of repeating disaccharide units with varying sulfate and uronic acid content.
**Option B:** Hyaluronic acid is a type of GAG and thus a heteropolysaccharide, playing a crucial role in maintaining tissue hydration and cell proliferation.
**Option C:** Chondroitin sulfate is another example of a GAG, which is also a heteropolysaccharide, contributing to cartilage structure and function.
**Clinical Pearl / High-Yield Fact**
Heteropolysaccharides, such as GAGs, are essential components of the extracellular matrix and play critical roles in various physiological and pathological processes, including tissue repair, inflammation, and cancer progression.
**Correct Answer:** C. Glycoproteins.