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!
From Molecules to the First Cell
The prebiotic conditions on the earth in all probability were volcanic eruptions, lightning and heavy rains. There was no trace of free oxygen or an ozone layer in the atmosphere to absorb ultraviolet radiations from the sun. It is assumed that organic molecules would have originated in such climatic conditions. This is described as their abiotic origin. Laboratory experiments from 1953 onwards prove that organic molecules like amino acids, proteins, nucleotides, nucleic acids, lipids and ATP can be formed in similar conditions on the earth. Stan1r.y Miller's experiment described below is one such experiment (Fig. shown below). It is possible that such organic molecules similar to those synthesised in Miller's experiment would have got accumulated at several places in high concentration, giving rise to a kind of liquid soup.
Scientists have three different speculatiohs about the composition of a protobiont. Some consider it'as an aggregate of electrically charged molecules with water around them acting as a boundary and this is called as coacervate model (Fig. shown below). This model was proposed by Alexander Oparin. Sidney Fox proposed another model for protobiont formation called protenoid microsphere model. According to this model when water free mixtures of amino acids are heated at high temperature, they pol.yinerise to form protein-like molecules, called proteinoids. These can persist only if cooled quickly. According to a third model called as the lipid bilayer model of Richard Goldacre, an abiotically synthesised phospholipid bilayer was formed around a central space containing organic molecules. All such models are without any experimental or theoretical evidence. However, the supporters of each model try to explain how some life-processes like osmosis and budding, can be camed out by such protobionts.
Why is the fish circulation classified as a simple and complete circulation? Complete circulation is that in which there is no mixture of venous blood and arterial blood. As ci
Until the Krebs cycle, aerobic respiration can be explained without mentioning oxygen, the chemical element after which the reaction gets its name. Where in the process does this c
Preputial prolapse This deformity is seen in some of the tropical zebu breeds but is not uncommon in European breeds. Initially, it begins as a temperory eversion of a small p
What are the main functions of the blood? The blood is a means of substance transportation all by the body. The blood distributes nutrients, oxygen, antibodies, hormones, and c
Explain the Future challenges for Neuroscience? When the analysis of single cells and even networks has progressed very nicely, there still remain many significant questions. A
Since neurotransmitters are not consumed in the synaptic process, what are the mechanisms to decrease their concentrations in the synaptic cleft after they have been used? As t
What are the processes involved in the preparation of plant tissue for free hand sectioning?
What is the best microscope to get a detailed view of the parts inside of a preserved plant cell?
Q. What are the major treatments of diabetes mellitus? The general goal of the diabetes curing is to keep normal glycemic levels. Type I diabetes is treated with parenteral
Q. Show the process of Healing abutment? Healing abutments are therefore not considered ideal. It is for this reason that the definitive abutment, selected at first stage surge
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