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.
POPUL A TIO N GENETICS AND EVOLUTION- Population is the number of all individual of same species in a defined area at a particular time. As per modem synthetic theory pop
Determine the term - Vascular disorders Normal central nervous system functioning can be affected by a number of vascular problems, because blood-vessel disease or damage can g
Analyse the model that highlights the factors which influence the environmental impact of a population
Central Nervous System Hypertension is one of the leading causes of cerebrovascular disease. It has been associated with accelerated age related cognitive decline. The most d
Explain the Physical Methods to Control Microorganisms? The physical methods to control microorganisms involve heat, filtration or radiations. Figure illustrates these methods.
Measurements of the level of pollution There are many factor for finding the level of pollution in the waste waters that generally find out the quantity of organic matter susp
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
using either nested brackets as a cladogram, what are the hierarchical relationships among the followingtaxa:raniates, amniotes, mammals, actinopterygians, chondrichthyes, aves, ve
Which of the following best explains the difference among dominant and recessive alleles? A. The recessive allele encodes a protein with normal activity whereas the dominant al
Are there living beings without cells? Viruses are measured the only living beings that do not have cells. Viruses are constitute by genetic material (DNA or RNA) enwrapped by
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