The cytoplasm houses various organelles, each with distinct functions and ultrastructural features:
Mitochondria Mitochondria are double-membraned organelles known as the powerhouse of the cell. Their inner membrane is highly convoluted, forming cristae that increase the surface area for ATP production. The matrix contains enzymes, mitochondrial DNA, and ribosomes, reflecting their role in energy metabolism and apoptosis.
Endoplasmic Reticulum (ER) The endoplasmic reticulum is categorized into the rough ER (RER) and smooth ER (SER). The RER is studded with ribosomes, giving it a rough appearance, and is involved in protein synthesis and modification. The SER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
Golgi Apparatus The Golgi apparatus consists of stacked, membrane-bound cisternae and is integral in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles. It plays a key role in post-translational modifications and the formation of lysosomes.
Lysosomes Lysosomes are spherical organelles containing hydrolytic enzymes necessary for intracellular digestion. Their membrane-bound structure protects the cell from the destructive action of these enzymes, which are crucial for breaking down waste materials and cellular debris.
Peroxisomes Peroxisomes contain enzymes that oxidize fatty acids and detoxify harmful substances like hydrogen peroxide. They are essential for lipid metabolism and the maintenance of cellular redox balance.
