1. Assess the endomembrane system and decide whether its evolution decreased or
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Question
1. Assess the endomembrane system and decide whether its evolution decreased or had no effect on the fitness of cells.2. Illustrate the geography (subcellular localization) of the components of the endomembrane system and label all the parts.
3. Explain how all parts of the endomembrane system acquire new membrane and new lipids.
4. Explain how the preassembled carbohydrate tree is assembled and then covalenetly linked to a protein in the endomembrane system.
5. Explain how a membrane vesicle is separated from the ER for transport to the golgi apparatus.
6. Describe how these vesicles are first target to the correct location in the endomembrane system and subsequently how they fuse into that endomembrane compartment.
1. Assess the endomembrane system and decide whether its evolution decreased or had no effect on the fitness of cells.
2. Illustrate the geography (subcellular localization) of the components of the endomembrane system and label all the parts.
3. Explain how all parts of the endomembrane system acquire new membrane and new lipids.
4. Explain how the preassembled carbohydrate tree is assembled and then covalenetly linked to a protein in the endomembrane system.
5. Explain how a membrane vesicle is separated from the ER for transport to the golgi apparatus.
6. Describe how these vesicles are first target to the correct location in the endomembrane system and subsequently how they fuse into that endomembrane compartment.
1. Assess the endomembrane system and decide whether its evolution decreased or had no effect on the fitness of cells.
2. Illustrate the geography (subcellular localization) of the components of the endomembrane system and label all the parts.
3. Explain how all parts of the endomembrane system acquire new membrane and new lipids.
4. Explain how the preassembled carbohydrate tree is assembled and then covalenetly linked to a protein in the endomembrane system.
5. Explain how a membrane vesicle is separated from the ER for transport to the golgi apparatus.
6. Describe how these vesicles are first target to the correct location in the endomembrane system and subsequently how they fuse into that endomembrane compartment.
Explanation / Answer
1. Endomembrane system is the system formed by the membranes of organelles like endoplasmic reticulum. ,Golgi bodies,nuclear envelope and lysosomes. Even the plasma membrane which is technically outside the cell is also included in this system.
Endoplasmic reticulum- It is divided into rough an smooth EPR. Rough EPR is rough because of the presence of ribosomes. Ribosomes help in the protein synthesis and the newly formed proteins go to the lumen of EPR to get modified or folded. Finally, modified proteins will move to their destinations like some will stay there, some will be secreted and some will be incorporated in the membranes. Those proteins which are not destined to stay there in EPR are packed in the vesicles and shipped to the Golgi apparatus.
Smooth endoplasmic reticulum does not have ribosomes. These are involved in the synthesis of carbohydrate, lipids and steroid hormones. Along with this storage of calcium ions occurs here. This also performs detoxification mechanisms.
Golgi apparatus- sorting, tagging, packaging, and distribution takes place in the Golgi apparatus. Here also a few modifications are made for example short stretches of carbohydrates are added to the proteins. Again many of the substances to be delivered are packed in the vesicles and send to their destinations such as the lysosome or vacuole.
Lysosomes- It is the organelle which contains digestive and hydrolytic enzymes. Lysosomes can also digest foreign particles that are brought into the cell from outside.
Obviously, the evolution of the endomembrane system in the eukaryotic cell has increased its fitness as compared to the prokaryotic cell which does not have this system. As we can see from the above discussion the endomembrane system is responsible for managing and regulating cell traffic in a proper manner. Lots of endosomes, vesicles, vacuoles are involved in it. Apart from this various types of modifications which are necessary for the protein functions is done here. These modifications are very important for few proteins and their functions. Similarly, lysosomes are the structures which are responsible for the killing of the foreign cells. All these organelles together have increased the fitness level of the cell.
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