Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
CELL MEMBRANE
As discrete units of life all living cells are separated from each other and from their external environment by an extremely delicate (75 A to 100 a= 0.00075 to 0.001 thick ) covering membrane invisible under light microscope. The covering is called cell membrane, plasma membrane, cytoplasmic membrane or plasmalemma . Its presence was presumably visualized by Naegeli and Cramer(1855) and confirmed by E. Overton(1899) who believed that it was a double layer of lipid molecules .Since then, scientists have been making efforts to properly elucidate the molecular structure of this membrane. Gorter and gremdel (1925) postulated that it was a bimolecular lipid layer formed mainly of polar lipids with the double hydrophobic tails of their molecules in both layers directed towards the interior of the membrane, and their polar , hydrophilic heads, at the two surfaces of the membrane.
Danielli and Davson (1935) ascertained that the plasma membrane contains a good amount of globular proteins in addition to the lipids. They postulated a lipid protein bilaye r moderl of membrane structure with hydrated globular protein molecules adsorbed upon both exposed surfaces of the original biomolecular lipid layer, forming a protein lipid sandwich Later (1954) Danielli further proposed that there were places where lipid bilayer is perforated by pores lined by protein molecules, only polar solute molecules and ions can pass through these pores.
Using electron microscopy Robertson (1959) observed that the plasma membrane has a characteristic trilaminar appearance in a dark light dark or railway track pattern . Each dark line consists of a pleated sheet of protein on surface and sheet of polar heads of lipid molecules, while the light central line consists of a bilayer of nonpolar fatty acid of lipid molecules Robertson .called the trilaminar structure a unit membrane which is continuous with certain membranous structures present inside a cell.
ELIZA stands for enzyme linked immune diffusion assays. It works on standard of antigen antibody reaction.
Describe about Congenital Cardiac Conditions Encountered in Adults ? The entire population of adults with CHD is constituted by patients whose cardiac malformations have a natu
SOM E COMMON REFLEXES RELATED TO RESPIRATION - 1. Cough Reflex: Due to stimulation in Trachea before it 2.5 lit. air is inhaled. 2. Sneezing Reflex: Stimulati
Mandibular Ramus Serves as an intraoral autogenous bone donor site. Cortical bone upto 4mm thickness may be harvested from the ramus. Harvest of bone from this area requires kn
Descent of the Testis The testis develops on the posterior abdominal wall at the mesonephric ridge. To reach the adult position in the scrotum, it must decent. A fibrous cor
Invertebrates - Osmotic and Ionic Regulation Regulation of water and ions in invertebrates is done by neuroendocrine mechanism. It operates at the level of Malpighian tubules
Temperature Stress We know that temperature alongwith water is an important influence on the geographical distribution and range of organisms. Every organism is restricted to a
Inter-relationships of Classification The aim of classification is to put together organisms on the basis of their similarities. But the question is what type of similarities?
Define the Drugs Effects on Excretion? Use of certain drugs can influence the excretion of certain substances. For example, besides their intended increase in sodium excretion,
Excluding the effects of cardiac output and hormones, describe the other factors that may affect blood pressure and blood flow in a middle-aged man who is exercising in an aerobics
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd