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.
What is PCR? How does PCR works? PCR, polymerase chain reaction, is a process to synthesize many copies of exact regions of a DNA molecule known as target-regions. Its inventor
Variation exhibited in shared traits present in a population is due to alleles of the shared genes. can be influenced by interactions of alleles of multiple genes. Can be influence
Q. What are the two major divisions of the chordate phylum? Chordates are divided into vertebrates and protochordates (urochordates and cephalochordates). Q. What are the d
What are the factors to an actual shift in the supply curve? Factors which cause an actual shift in the supply curve are described in below: When prices rise or fall this wo
How different are the endosperm of gymnosperms and the endosperm of angiosperms? In gymnosperms the endosperm is haploid (n), it is known as primary endosperm. In angiosperm th
At the beginning of the process in an animal cell, the partition of the centriole takes place, which has been duplicated during Interphase but were in the same centrosome. Bipol
organism that have wide tolerance range
Q. How does the intensity of simple diffusion differ in relation to the concentration gradient of the moved substance? The higher the concentration gradient of a substance the
The cost of replacing these indirect uses of biodiversity, even if it were technically possible, would be so high as to render it impossible to duplicate. We also do not know how
Deinococcus radiodurans is a bacterium that was isolated from cooling ponds in and around nuclear power plants. It is highly resistant to ionizing radiation. Propose a hypothesis t
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