Question

1. In eukaryotes, the primary rRNA transcript is a 45S rRNA that includes the sequences of the 18S, 5.8S and 28S rRNA separated by short spacers. What is the advantage of this operon-like arrangement of the rRNA genes?

2. Electron micrographs of human nerve fibers show 10-15 layers of membranous myelin sheath. Upon close examination, these membranes are particularly rich in sphingolipids especially the glycosphingolipids. What could be the reason why these types of lipids abound in human myelin?

3. The family of substances called eicosanoids consists of prostaglandins, leukotrienes and thromboxanes. What is their relationship with any form of lipids?

Answer 1

1.In eukaryotes the advantage of this rRNA operon is given below :-

• it provides the advantage of the initiation of transcription at one point and transcribe many genes. Like 18S, 5.8S and 28s all are transcribed together then assembled to form small sub unit of ribosome.
• Here separate promoters, multiple transcription antivation factors are not required.  
• The rRNA operons helps for increasing the level of ribosome, which is required for protein synthesis or translation.

2. Mainly The glycosphingolipids are found in human myelin because :-

• their carbohydrate group is responsible for the interaction between individual cells and for signaling.
• Their hydrocarbon chains of strengthen the myelin sheath.

3. Eicosanoids are generally categorized into four different families: prostaglandins, prostacyclins, thromboxanes, and leukotrienes. Their relation with any lipuds is to maintain a variety of effects in our body. They act as bioactive signaling lipids derived from arachidonic acid and related polyunsaturated fatty acids (PUFAs), which mainly regulates a variety of functions like-minded homeostatic and inflammatory processes or fever promotion, blood pressure regulation, and blood clotting. They also influence the immune response, respiratory and some of the reproductive processes.

I hope this answer will definitely help you. Please give me likes. All the best. THANK YOU STAY SAFE.