Cell Organelles: Meaning, Categories of Cell Organelles, Cell Organelles, and Their Functions (For CBSE, ICSE, IAS, NET, NRA 2022)

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Meaning of a Cell Organelle

• A cell organelle can be defined as a specialized entity present inside a cell.
• This specialized entity performs a specific function.
• The cell organelles are membrane-bound being present within the cells and with distinct structures and functions.
• A subcellular structure that has one or more specific jobs to perform in the cell is called an organelle.
• The most important cell organelles are the nuclei, mitochondria, and ribosomes.

Three Categories of Cell Organelles

Organelles Without Membrane

This includes the Cell wall, Ribosomes, and Cytoskeleton being present both in prokaryotic cell and the eukaryotic cell.

Single Membrane-Bound Organelles

This includes Vacuole, Lysosome, Golgi apparatus, Endoplasmic Reticulum present only in a eukaryotic cell.

Double Membrane-Bound Organelles

Mitochondria and chloroplast are double membrane-bound organelles both being present in in a eukaryotic cell.

Cell Organelles and Their Functions

Plasma Membrane

• It is also known as a Cell Membrane or Cytoplasmic Membrane.
• The membrane is composed of a lipid bilayer and proteins.
• The membrane is present both in animal and the plant cell.
• It performs some very important functions such as providing shape, protecting the inner organelle of the cell, and acting as a selectively permeable membrane.

Centrosomes

• Centrosomes consist of Centrioles and are found only in the animal cells.
• It plays an important function of organizing the microtubule and Cell division.

Cytoplasm

• It is a jelly like substance consisting of water, dissolved nutrients, and waste products of the cell.
• The metabolic activities of the cell are performed by cytoplasm.

Chloroplasts

• These are present only in plant cells containing a green colored pigment called chlorophyll.
• Chloroplasts serve as the sites of photosynthesis.

Golgi Apparatus

• This is a membrane bound sac-like organelles, present within the cytoplasm of the eukaryotic cells.
• Functions like secretion and intracellular transport are performed by the Golgi apparatus.