The main difference between cholesterol and ergosterol is that cholesterol is a waxy substance needed to synthesize hormones and vitamin D, whereas ergosterol is the major sterol that occurs in the plasma membrane of yeast and fungi.
Cholesterol and ergosterol are two fatty substances that occur in the cell membrane. They are sterols.
Key Areas Covered
1. What is Cholesterol
– Definition, Structure, Function
2. What is Ergosterol
– Definition, Structure, Function
3. Similarities Between Cholesterol and Ergosterol
– Outline of Common Features
4. Difference Between Cholesterol and Ergosterol
– Comparison of Key Differences
Key Terms
Cholesterol, Ergosterol
What is Cholesterol
Cholesterol is a steroid, which is a modified sterol. It is a type of lipid that occurs in the body. Cholesterol comes into the body through the diet. Also, the liver produces most of the cholesterol. Basically, the cholesterol molecule consists of four rings (A, B, C, D) with trans ring junctions, two methyl groups (C-18 and C-19), a hydroxyl group on C-3, and an iso-octyl side-chain at carbon 17. Therefore, it is a tetracyclic cyclopenta[a]phenanthrene. Additionally, both methyl and hydroxyl groups occur above the plane. However, a double bond occurs between C-5 and C-6. Typically, cholesterol is a hydrophobic molecule with a rigid planar four-ring nucleus with a flexible tail.
Figure 1: Cholesterol
Furthermore, cholesterol performs vital functions in the body. Usually, it serves as an essential structural component of the cell membrane of animals. It also serves as a precursor for the synthesis of steroid hormones, bile acids, and vitamin D inside the body. Besides, it forms the myelin sheath, which electrically insulates the axon of the neurons to increase the speed of signal transmission.
What is Ergosterol
Ergosterol is another sterol that occurs in the plasma membrane of fungi. Its function is to maintain the integrity of the plasma membrane. Also, ergosterol is the precursor of vitamin D2; exposure to UV light produces vitamin D2 from ergosterol. Since it occurs in the plasma membrane, ergosterol is an evolutionary important steroid. Additionally, the conjugated double-bond structure of the ergosterol gives antioxidant properties to ergosterol. Importantly, ergosterol is absent in animals. Therefore, it is a useful drug target for antifungal drugs. It is present in the cell membrane of protists.
Figure 2: Ergosterol
Moreover, amphotericin B is an example of an antifungal drug that targets ergosterol. It binds to ergosterol in the plasma membrane. Fluconazole, itraconazole, miconazole, clotrimazole, and myclobutanil are other examples of antifungal drugs that target ergosterol.
Similarities Between Cholesterol and Ergosterol
- Cholesterol and ergosterol are two fatty substances that occur in the plasma membrane of living organisms.
- They are important for maintaining the plasma membrane integrity.
- They are sterols.
Difference Between Cholesterol and Ergosterol
Definition
Cholesterol refers to a compound of the sterol type found in most body tissues. In contrast, ergosterol refers to a compound present in ergot and many other fungi.
Structure
Cholesterol consists of a central sterol nucleus of four hydrocarbon rings, while ergosterol consists of an additional double bond in the hydrocarbon ring and a double bond and methyl group in the alkyl side chain.
Occurrence
Cholesterol is a constituent of the cell membrane of mammals, while ergosterol occurs in the cell membrane of fungi and yeast.
Function
Cholesterol serves as a precursor for hormones and vitamin D, while ergosterol serves as a precursor for vitamin D2.
Conclusion
In brief, cholesterol and ergosterol are two steroid compounds that occur in the plasma membrane of living organisms. Cholesterol is a steroid compound that occurs in most body tissues. It consists of a central sterol nucleus of four hydrocarbon rings. Also, it is a constituent of the cell membrane and serves as a precursor for hormones and vitamin D. In comparison, ergosterol is another steroid compound that occurs in the plasma membrane of fungi and yeast. However, it serves as a precursor for vitamin D2. Therefore, the main difference between cholesterol and ergosterol is their structure and function.
References:
- S. National Library of Medicine. (n.d.-a). Cholesterol. MedlinePlus.
- Ergosterol. Ergosterol – an overview | ScienceDirect Topics. (n.d.).
Image Courtesy:
- “Cholesterol” By BorisTM – Own work (Public Domain) via Commons Wikimedia
- “Ergosterol structure” By User:Mysid – Own Work (Public Domain) via Commons Wikimedia
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