harmful compounds. . . Golgi Body (Dictyosomes) In , Camillo Golgi visualized a netlike reticulum of fibrils near the nucleus, were named as Golgi bodies.
In plant cells they are found as smaller vesicles termed as Figure . : Structure of an Endoplasmic reticulum • Secretion of carbohydrates for the formation of plant cell walls and insect cuticles. • Zymogen granules (proenzyme/precursor of all enzyme) are synthesised. Figure .
: Exocytosis . . Mitochondria It was first observed by A. Kolliker ( ).
Altmann ( ) named it as Bioplasts. Later Benda ( , ), named as mitochondria. They are ovoid, rounded, rod shape and pleomorphic structures. Mitochondrion consists of double membrane, the outer and inner membrane.
The outer membrane is smooth, highly permeable to small molecules and it contains proteins called Porins , which form channels that allows free diffusion of molecules smaller than about daltons and the inner membrane divides mitochondrion into two compartments, outer chamber between two membranes and the inner chamber is filled with matrix. The inner membrane is convoluted (infoldings), called crista (plural: cristae). Cristae contain most of the enzymes for electron transport system. Inner chamber of the mitochondrion is filled with proteinaceous material called mitochondrial matrix .
The Inner membrane consists of stalked particles called elementary particles or Fernandez Moran particles , F1 particles or Oxysomes. Each particle consists of a base, stem and a round head. In the head, ATP synthase is present for oxidative phosphorylation. Inner membrane is impermeable to most ions, small molecules and maintains the proton gradient that drives oxidative phosphorylation (Figure .
). Figure . : Structure of Mitochondria Mitochondria contain % of proteins, - % of lipids, - % of RNA, DNA (in traces) and enzymes (about types). Mitochondria are called Power house of a cell , as they produce energy rich ATP.
All the enzymes of Kreb’s cycle are found in the matrix except succinate dehydrogenase. Mitochondria consist of circular DNA and 70S ribosome. They multiply by fission and replicates by strand displacement model. Because of the presence of DNAs it is semi- autonomous organelle.
Unique characteristic of mitochondria