英国代写论文：地球上生命起源的假说

英国代写论文：地球上生命起源的假说。有一些科学家认为，当来自其他星球的孢子传播到这个星球时，生命就开始了，这个过程被称为生源说(Lal, 2008)。然而，当一个人谈论生命及其延续时，他会着眼于遗传、转化、能量和生长等等。地球上的生命一直都是由细胞构成的，它们是结构和基本单位。这些细胞有细胞膜，将细胞内容物与外部环境分开。这种细胞膜是由有机分子组成的，其中含有氧、氮、氢、硫、碳和磷酸盐，这些分子发展成了现在的生命形式。因此，我们需要追溯这种进化，以理解整个过程是如何开始的。在接下来的内容中，英国代写论文专家将分析下地球上生命起源的假说。

有人曾提到，支持化学变化是产生生命的最重要过程的科学证据并不存在，但人们并不缺乏支持不同理论的不同假设，特别是与解释自然过程有关的假设。描述这些过程是很重要的，因为它与目前支持上述过程的地质证据是一致的。也有一些步骤需要讨论:

生命起源于简单的细胞，这些细胞有由有机分子组成的细胞膜。这些有机分子含有单糖和核苷酸，这些物质现在也存在于所有细胞中。

在酶的帮助下，这些分子通过催化反应生成聚合物。这些基因被发现包含遗传信息，有助于基因链的复制和编码(Fox, Dose and Oparin, 1997)。

原始细胞或RNA随着聚合物复制细胞是细胞内和系统内发生代谢反应的必要条件。当这一过程在细胞内发生时，膜是细胞内容物与外部环境分离的唯一途径。膜是一种脂质双分子层，具有半透性和疏水性(Oparin, 2003)。

我们可以有把握地说，不管支持地球上生命起源的假设是什么，都有一个共同的结论，那就是具有遗传信息的细胞复制。这意味着遗传特征和特征已经被传递，细胞膜允许不同的生命过程在细胞内发生。

这就引出了下一个问题，如果有机分子存在或形成了，它们又如何对地球上生命和细胞的形成起作用呢?很少有实验和理论试图证明这一点。

Miller-Urey实验:该实验起源于20世纪50年代，研究有机分子和无机化合物的形成，以产生我们讨论过的东西，并得出结论，它被活细胞用于复制和生长(Urey, 1952)。

地球是一个曾经有过彗星、陨石和伴随而来的尘埃的地方。

当对这些尘埃颗粒进行分析时，发现它们也含有有机分子。它们可能形成了细胞和生命的分子。它们的存在也更容易解释，因为它们可能来自以下三种来源中的任何一种:有低温喷口的海床，米勒-尤里化学提供的解释，以及来自外太空或其他行星的粒子。

人们的猜测一直围绕着这些有机分子的起源、存在和形成。这是因为有机分子的存在，它们的浓度，它们形成聚合物和氨基酸的能力，这些聚合物和氨基酸进一步形成多肽链，不断折叠并产生更多的蛋白质分子，这也可以说是生命的基础。这些过程连同核糖(糖的形式)、磷酸盐和含氮碱基组成RNA和DNA，它们是遗传学和遗传的关键，因此也是理解生命如何在地球上起源的重要途径(霍尔丹，1980)。

It has been mentioned that scientific evidence supporting the chemical change as the foremost process giving rise to life is not present, but one does not lack the different hypotheses supporting different theories, especially the ones related to explaining the natural processes. These processes are important to be described because it is in consistent with the geological evidence present which supports the above-mentioned process. There are few steps which need to be discussed as well:

Origin of life started from simple cells and these cells had cell membranes made out of organic molecules. These organic molecules had simple sugars and nucleotides which are also present in all cells in present day.

There was polymers formation from those molecules, followed by catalytic reactions with the help of enzymes. These are found to contain hereditary information and helps in replication and encoding of strands (Fox, Dose and Oparin, 1997).

Protocells or RNA replicating cells along with the polymers are requisites for metabolic reactions to take place, within the cell, and within the systems. When this is taking place within a cell the membrane is the only line of separation of the contents of the cells from the external environment. The membrane is a lipid bilayer which is semi permeable and is hydrophobic (Oparin, 2003).

One can safely say that irrespective of the hypothesis which supports the origin of life on earth, it all has a common conclusion which is replication of cells with genetic information. This meant that the hereditary character and the traits have been passed on, and the membranes allow the different life processes to take place within the cell.

This brings one to the next question which is if the organic molecules existed or were formed, how were they further responsible for formation of life and cells on the earth. There are few experiments and theories which try to prove this.

Miller-Urey experiment: This experiment originated back in 1950s where the formation of the organic molecules along with inorganic compounds was studied to produce what has been discussed, and conclude, it was used by cells which are alive to replicate and grow (Urey, 1952).

The earth is a place where there have been comets and meteorites and the dust that comes along with.

When the dust particles were analysed, it was seen that they had organic molecules as well. They could have been forming molecules of cells and of life. Their presence is easier to explain as well because they could have come from any of the three sources which are: the sea beds having hypothermal vents, the explanation provided by Miller-Urey chemistry and the particles from outer space or other planets.

The speculation has always been around the origin, the presence and the formation of these organic molecules. The reason for this is that the presence of organic molecules, their concentrations, their ability to form polymers and amino acids which further makes chains of polypeptides, keep folding themselves and make more molecules of protein, which again can be said is the base of life. These processes along with ribose (form of sugar), phosphate and nitrogenous base make RNA and DNA, which holds the key to genetics and hereditary, and thus and important way of understanding how life originated on the planet (Haldane, 1980).

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