cytoplasm
What is cytoplasm?
What are some functions of the cytoplasm?
What organelles are found in the cytoplasm?
What is the cytoskeleton and its function?
cytoplasm, the semifluid substance of a cell that is external to the nuclear membrane and internal to the cellular membrane, sometimes described as the nonnuclear content of protoplasm. In eukaryotes (i.e., cells having a nucleus), the cytoplasm contains the organelles, suspended in the cytosol, a concentrated aqueous solution rich in enzymes, ions, and metabolites that serves as the site of many metabolic reactions, including portions of cellular respiration and biosynthesis.
- Cytosol: the fluid portion where metabolic reactions and other cellular processes occur.
- Organelles: specialized structures such as mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes.
- Cytoskeleton: a network of protein filaments that provides structure and enables movement.
Among such organelles are the mitochondria, which generate energy in the form of ATP (adenosine triphosphate) through oxidative phosphorylation; the endoplasmic reticulum, consisting of rough (ribosome-studded) regions involved in protein synthesis and smooth regions associated with lipid synthesis and detoxification; and the Golgi apparatus, which modifies, sorts, and packages proteins and lipids for transport. Lysosomes contain hydrolytic enzymes for intracellular digestion, while peroxisomes, carry out oxidative reactions involved in detoxification and lipid metabolism.
The cytoplasm also contains the cytoskeleton, a dynamic network of microfilaments, intermediate filaments, and microtubules that provides structural support, facilitates intracellular transport, and enables cell movement. In addition, the cytoplasm is a site of vesicular trafficking, where transport vesicles shuttle materials between organelles and to the cell membrane. Together, these components make the cytoplasm a highly organized and active environment essential for maintaining cellular function and coordination.
