NEET BIOLOGY

Detailed explanation-1: -The ER has a central role in lipid and protein biosynthesis. Its membrane is the site of production of all the transmembrane proteins and lipids for most of the cell’s organelles, including the ER itself, the Golgi apparatus, lysosomes, endosomes, secretory vesicles, and the plasma membrane.

Detailed explanation-2: -The endomembrane system (endo-= “within”) is a group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins.

Detailed explanation-3: -In eukaryotic cells, the membrane that surrounds the nucleus-commonly called the nuclear envelope-partitions this DNA from the cell’s protein synthesis machinery, which is located in the cytoplasm.

Detailed explanation-4: -Membranes and their constituent proteins are assembled in the ER. This organelle contains the enzymes involved in lipid synthesis, and as lipids are manufactured in the ER, they are inserted into the organelle’s own membranes. This happens in part because the lipids are too hydrophobic to dissolve into the cytoplasm.

Detailed explanation-5: -The plasma membrane Both prokaryotic and eukaryotic cells have a plasma membrane, a double layer of lipids that separates the cell interior from the outside environment. This double layer consists largely of specialized lipids called phospholipids.