granular component

Definition

Target type: cellularcomponent

A structure found in the nucleolus, which contains nearly completed preribosomal particles destined for the cytoplasm. [PMID:10754561]

Granular components are subcellular structures found within the cytoplasm of eukaryotic cells. They are characterized by their granular appearance, often containing densely packed particles or granules. These granules can be composed of various materials, including proteins, lipids, carbohydrates, and nucleic acids. Granular components play diverse roles in cellular function, including:
Storage and release of cellular materials: Granules can serve as storage sites for various molecules, such as enzymes, hormones, and signaling molecules. When needed, these granules can release their contents into the cytoplasm or extracellular space.
Cellular detoxification: Certain granular components, such as lysosomes and peroxisomes, are involved in detoxification processes. They break down and neutralize harmful substances, including toxins, reactive oxygen species, and waste products.
Cellular signaling: Some granules contain signaling molecules that are involved in intracellular and intercellular communication. They can trigger specific cellular responses, such as gene expression, cell growth, and apoptosis.
Ribosomes and polyribosomes: These are granular components responsible for protein synthesis. Ribosomes are made up of ribosomal RNA (rRNA) and proteins. Polyribosomes are groups of ribosomes attached to a messenger RNA (mRNA) molecule, allowing for efficient translation of proteins.
Secretory granules: These granules are responsible for packaging and releasing proteins and other molecules outside the cell. They are often found in cells that produce hormones, enzymes, and other secreted substances.
Examples of granular components include:
Lysosomes: Membrane-bound organelles that contain hydrolytic enzymes for breaking down cellular waste and debris.
Peroxisomes: Membrane-bound organelles involved in the breakdown of fatty acids and detoxification of reactive oxygen species.
Golgi apparatus: A stack of flattened membrane-bound sacs involved in protein modification, sorting, and packaging.
Endoplasmic reticulum (ER): A network of interconnected membranes involved in protein synthesis, lipid synthesis, and detoxification.
Mitochondria: Double-membrane-bound organelles involved in energy production through cellular respiration.
The specific composition and function of granular components vary depending on the cell type and its physiological state. They are essential for maintaining cellular homeostasis and carrying out various cellular processes.'
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Proteins (2)

Compounds (6)