病毒是细胞内专性寄生虫,这意味着它们在没有活细胞的帮助下不能复制或表达它们的基因。单个病毒颗粒(病毒颗粒)本身基本上是惰性的。它缺乏细胞必须复制的必需成分。当病毒感染细胞时,它会整合细胞的核糖体,酶和大部分细胞机器进行复制。与我们在有丝分裂和减数分裂等细胞复制过程中看到的不同,病毒复制产生许多后代,当完成后,让宿主细胞感染生物体中的其他细胞。病毒可含有双链DNA,双链RNA,单链DNA或单链RNA。在特定病毒中发现的遗传物质的类型取决于特定病毒的性质和功能。宿主被感染后发生的确切性质取决于病毒的性质。双链DNA,单链DNA,双链RNA和单链RNA病毒复制的过程将有所不同。例如,双链DNA病毒通常必须在它们可以复制之前进入宿主细胞的细胞核。然而,单链RNA病毒主要在宿主细胞的细胞质中复制。一旦病毒感染其宿主并且宿主的细胞机器产生病毒后代组分,病毒衣壳的组装是非酶促过程。它通常是自发的。病毒通常只能感染有限数量的宿主(也称为宿主范围)。 “锁定和键”机制是此范围的最常见解释。病毒颗粒上的某些蛋白质必须适合特定宿主细胞表面的某些受体位点。

澳大利亚维多利亚大学医药学Essay代写:了解病毒复制的发生方式

Viruses are intracellular obligate parasites, which means that they cannot replicate or express their genes without the help of a living cell. A single virus particle (virion) is in and of itself essentially inert. It lacks needed components that cells have to reproduce. When a virus infects a cell, it marshals the cell’s ribosomes, enzymes and much of the cellular machinery to replicate. Unlike what we have seen in cellular replication processes such as mitosis and meiosis, viral replication produces many progeny, that when complete, leave the host cell to infect other cells in the organism. Viruses may contain double-stranded DNA, double-stranded RNA, single-stranded DNA or single-stranded RNA. The type of genetic material found in a particular virus depends on the nature and function of the specific virus. The exact nature of what happens after a host is infected varies depending on the nature of the virus. The process for double-stranded DNA, single-stranded DNA, double-stranded RNA and single-stranded RNA viral replication will differ. For example, double-stranded DNA viruses typically must enter the host cell’s nucleus before they can replicate. Single-stranded RNA viruses however, replicate mainly in the host cell’s cytoplasm. Once a virus infects its host and the viral progeny components are produced by the host’s cellular machinery, the assembly of the viral capsid is a non-enzymatic process. It is usually spontaneous. Viruses typically can only infect a limited number of hosts (also known as host range). The “lock and key” mechanism is the most common explanation for this range. Certain proteins on the virus particle must fit certain receptor sites on the particular host’s cell surface.

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