BIO Lecture Notes - Lecture 1: Endoplasmic Reticulum, Lipid Bilayer, Golgi Apparatus
20 Oct 2022
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Document Summary
The cell is the smallest structural and functional unit of the body. The human body contains about 100 trillion cells. A typical cell, as seen by the light microscope, consists of three basic components: Fig:structure of a typical cell (in the centre) showing various organelles: a, mitochondrion; b, endoplasmic reticulum (rough and smooth); c, golgi apparatus; d, centrosome; e, nucleus and f, secretory granules. Cell membrane or the plasma membrane is the protective sheath enveloping the cell body. It separates the contents of cell from the external environment and controls exchange of materials between the fluid outside the cell (extracellular fluid) and the fluid inside the cell (intracellular fluid) Singer and nicholson put forward the fluid mosaic model of membrane structure. Phospholipid bilayer is the basic continuous structure forming the cell membrane. This fluidity makes the membrane quite flexible and thus allows the cells to undergo considerable changes in the shape without disruption of structural integrity.
