One of the following membrane system is consideredto be extension of i...
The endoplasmic reticulum (ER) is a type of organelle found in eukaryotic cells that forms an interconnected network of flattened, membrane-enclosed sacs or tube-like structures known as cisternae. The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum occurs in most types of eukaryotic cells, but is absent from red blood cells and spermatozoa. There are two types of endoplasmic reticulum: rough (granular) and smooth (agranular). The outer (cytosolic) face of the rough endoplasmic reticulum is studded with ribosomes that are the sites of protein synthesis. The rough endoplasmic reticulum is especially prominent in cells such as hepatocytes. The smooth endoplasmic reticulum lacks ribosomes and functions in lipid manufacture and metabolism, the production of steroid hormones, and detoxification.The smooth ER is especially abundant in mammalian liver and gonad cells.
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One of the following membrane system is consideredto be extension of i...
Endoplasmic Reticulum:
The endoplasmic reticulum (ER) is a membrane system that is considered to be an extension of the infolded plasma membrane. It is a network of membranous tubules and sacs that are interconnected and spread throughout the cytoplasm of eukaryotic cells. The ER plays a crucial role in various cellular processes including protein synthesis, lipid metabolism, and calcium storage.
Structure of Endoplasmic Reticulum:
- The ER has two main regions: the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER).
- The RER is studded with ribosomes on its surface, giving it a rough appearance under a microscope. These ribosomes are responsible for protein synthesis.
- The SER lacks ribosomes and appears smooth under a microscope. It is involved in lipid metabolism, detoxification of drugs and toxins, and the storage and release of calcium ions.
Function of Endoplasmic Reticulum:
- Protein Synthesis: The RER plays a crucial role in the synthesis, folding, and modification of proteins. It is responsible for the synthesis of membrane proteins, secretory proteins, and proteins that are targeted to other organelles.
- Lipid Metabolism: The SER is involved in the synthesis of lipids, including phospholipids and steroids. It also plays a role in the detoxification of drugs and toxins by modifying them to make them more water-soluble for excretion.
- Calcium Storage and Release: The SER is responsible for storing calcium ions. These ions can be released into the cytoplasm when needed, playing a crucial role in various cellular processes such as muscle contraction and signaling.
- Membrane Biogenesis: The ER is involved in the biogenesis of new membranes. It provides the necessary lipids and proteins for the formation of new membranes during cell growth and division.
In conclusion, the endoplasmic reticulum is considered to be an extension of the infolded plasma membrane. It is a complex membrane system that plays a crucial role in protein synthesis, lipid metabolism, calcium storage, and membrane biogenesis. The ER is composed of the rough endoplasmic reticulum (RER), which is involved in protein synthesis, and the smooth endoplasmic reticulum (SER), which is involved in lipid metabolism and calcium storage.
One of the following membrane system is consideredto be extension of i...
Option b is correct answer
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