病毒的复制过程的英语作文

病毒的复制过程的英语作文
The basic chemical composition of a virus is very simple,consisting mainly of nucleic acids and proteins.Among them,nucleic acid(DNA or RNA)carries all the genetic information of the virus and is the material basis for its reproduction(proliferation).However,viruses lack the enzymes necessary to proliferate and can only replicate themselves within the host cell.So in general,viruses don't want to kill their hosts.So why do SARS,MERS,Ebola and this one,20XX-NCOV,all have such a high fatality rate?The logic is that these viruses have not yet identified humans as suitable hosts,and may take some time to fall in love and kill each other.
Most viruses replicate in six steps:
Adsorption,invasion,uncoating,biosynthesis,assembly and release.Among them,adsorption is the key to the success of infection and the core of its specificity.The adsorption of viruses to cells requires a specific match between the adsorption proteins on the virus surface and the cell surface receptor.It's like docking a space shuttle with a space station.It requires a precise match.It has been shown in the literature that novel Coronavirus 20XX-NCOV has achieved specific adsorption through the interaction of its spike protein with human ACE2 protein(Science China--Life Sciences:Novel Coronavirus 20XX-NCOV Evolution and Protein Modeling of human transmission risk in XX Outbreak).
The binding of viral proteins to cell surface receptors requires temperature conditions to facilitate chemical reactions similar to those of enzymes.The higher the temperature is within 0-37℃,the higher the virus adsorption efficiency is.That's why it's been rumored that taking a hot bath can prevent infection,but you have to be very
temperature-sensitive.
After the virus is attached to the cell,it needs to enter the host cell through different ways,namely the invasion process,which generally includes injection invasion,endocytosis,membrane fusion,etc.Injectable invasion,more intuitive,is our common"injection".This is a common way for a tailed phage to invade.The DNA genome from the capsid is injected into a host(usually a bacterium)cell by tail contraction.
Endocytosis is a common way of entry of animal viruses.After the virus rivets the cell,the change of membrane tension causes it to invaginate and form phagocytic vesicles,allowing the virus particles to enter the cytoplasm.Molecular dynamics simulations are often used to recreate this process with nanoparticles.It's like feeding a fish when a bait floats on the surface of the water and is sucked in by the mouth of a goldfish.
In addition,membrane fusion is an invasion mode in which the virus envelope and cell membrane fuse during the invasion of enveloped viruses.There are some viruses and cell surface receptor binding,by the
cell surface enzymes to help the release of nucleic acid plasmid into the cytoplasm,the virus capsid remains outside the membrane,its invasion and unhullingu into one.
The next step is uncoating,which refers to the release of the nucleic acid,the core component of the virus,from the protein capsid.The uncoating of enveloped virus includes two steps:uncoating and uncoating,while uncoated virus only needs uncoating.Injectable phages invade and uncoats simultaneously on the surface of cell membrane or cell wall.Endocytosis of the virus into the cell,through enzymatic degradation,the envelope and capsid successively removed.When the virus is invaded by membrane fusion,its envelope is removed when it fuses with the cell membrane,and the capsid is moved to the site of uncoating and further uncoating under the action of enzyme,and the viral nucleic acid dissociates and advances to a certain part of the cell for biosynthesis.The virus shucking must involve enzymes from the host cell.
The virus then synthesizes nucleic acids and proteins with the help of raw materials,energy and premises provided by the host cell,which also supplies most of the enzymes needed for the process.There are no virus particles in the cytoplasm during the biosynthesis stage after the virus enters the host cell.That's the incubation period.After the nucleic acid and protein synthesis of the main components of the virus,the nucleocapsid is assembled in the nucleus or cytoplasm.Most DNA viruses
assemble in the nucleus,while RNA viruses assemble in the cytoplasm.The nucleating capsid of an unenvelopeds virus is the mature virion.
When most unenvelopeds viruses are released,the infected cell disintegrates,releasing virus particles,destroying the host cell membrane,and immediately killing the cell.The vast majority of enveloped viruses become mature viruses by budding through endoplasmic reticulum,vacuoles,or enveloping cell nuclear membrane or cell membrane.They are released one by one in a period of time,causing light damage to cell membrane and slow death of host cells.The process from the adsorption of a single virus to the release of all viruses is called the infection cycle or replication cycle.An infected cell typically releases between 100 and 1000 viruses.。