structural biology of membrane proteins

. The most significant of these is their role as biological catalysts enzymes. Apart from this, proteins are important to a cell as structural components necessary for growth, repair and regeneration. Proteins also have significant role in the transport of re..

The cell membrane and the membranes of various cell structures exhibit the same structure and as such perform the same functions. However, the amount and arrangement of phospholipids and proteins varies in different cells and organelles. This variat..

Plasma Membrane - The plasma membrane or cell membrane surrounds the cell contents in all types of cells. It is a multipurpose covering composed of phospholipids and proteins. fig. 16.4 - Cell Membrane Apart from the plasma membrane, an eu..

Unit Membrane Concept - The molecular structure of cell membrane is still not clearly known. Several models have been proposed from time to time to explain its structure based on its physico-chemical properties. In the year 1935 Danielli and Dawson proposed t..

The cytoplasm contains a fine network of fibrous protein elements that form a framework for supporting the extensively branched membranes found in the relatively fluid cytoplasmic matrix. This framework is called cytoskeleton. It is found to be composed of three types of organel..

>Plastids are spherical or oval cell organelles found only in plant cells. Plastids are of two types: leukoplasts without any colouring pigments and chromoplasts containing colouring pigments. The most familiar chromoplasts are the chloroplasts containing chlorophyll. Lysosomes are organelles bound..

In the year 1972 Singer and Nicolson proposed a model for explaining the membrane structure, taking into account all the known facts. According to this model, cell membrane consists of a highly viscous fluid matrix of a bilayer of phospholipids having globular pro..

These are long, slender thread-like structures, which help in locomotion. A bacterial cell may have one to many flagella. The flagella are entirely composed of a protein called flagellin. The basal body of each flagellum is directly attached to the plasma membrane. It..

. The membrane encloses a clear fluid matrix called nucleoplasm or karyolymph. It encloses a fine network of thread-like structures, called chromatin network. It is composed of chromatin that contain DNA and histones arranged in a specific manner. The chromatin condenses to form..

Mitochondria are tiny structures that occur in varying shapes cylindrical, spherical, oval, rod shaped etc. They are found distributed all over the cytoplasm. fig. 16.6 - Mitochondria Each mitochondrion is bound by a double membrane. The outer membrane is smooth and st..