Cell Structure

The cell is defined as the smallest structural and functional unit of life, containing a nucleus at its center and surrounded by a cell membrane. There are two types of cells: plant and animal cells.

Plant cell diagram:

Animal Cell Diagram:

Both plant and animal cells consist of the following components/organelles:

Organelle	Function
Cell Membrane	It is semi-permeable, allowing for the selective exchange of materials in and out of the cell.
Nucleus	Stores and carries hereditary information from generation to generation. It translates genetic information into proteins characteristic of the cell and controls the cell’s life processes.
Mitochondrion	Site of cellular respiration for energy production. It contains enzymes and DNA that convert ADP to ATP.
Endoplasmic Reticulum (ER)	Aids in the transport of materials within the cytoplasm. Rough ER (with ribosomes) is for protein synthesis and transportation, while Smooth ER is for lipid and steroid synthesis and transportation.
Golgi Bodies/Apparatus	Involved in the synthesis, packaging, and distribution of materials.
Lysosomes	Site for the production of enzymes for digestion and the destruction of worn-out cells.
Vacuole	Surrounded by a membrane called tonoplast, it contains cell sap, mineral salts, and sugar, and acts as an osmoregulator by removing excess water.
Cytoplasm	The medium for all cellular reactions.
Ribosome	Synthesis of proteins.
Chloroplast	Contains chlorophyll for photosynthesis in green plants.
Cell Wall	Provides protection, shape, and support to the cell and allows free passage of materials in and out.
Centrioles	Important in cell division.

Differences Between Plant and Animal Cells

Plant Cell	Animal Cell
Has chloroplasts	No chloroplasts
Has a definite shape	No definite shape
Has a rigid cellulose cell wall	No cell wall
Centrioles are absent	Centrioles are present for cell division
Presence of a large central permanent vacuole	Vacuoles are small and temporary, or absent
Starch granules present	Glycogen granules present