Corona virus | Additional Study Material for NEET PDF Download

Type of strains:-

There are seven strains of corona virus

• Human Coronavirus 229E (HCoV-229E)
• Human Coronavirus NL63 (HCoV-NL63, New Haven Corona Virus)
• Human Coronavirus OC43(HCoV-OC43)
• Human Coronavirus HKU1
• Middle East Respiratory Syndrome Related Coronavirus (MERS-CoV) previously known as novel coronavirus 2012 & HCoV-EMC
• Severe Acute Respiratory Syndrome Coronavirus, previously known as SARS CoV, or SARS Classic
• Severe Acute Respiratory Syndrome Coronavirus -2,  (SARS CoV-2), previously known as 2019-nCoV, or “novel Coronavirus-2019”

How SARS CoV-2 infect human:-

Host ACE-2 protein act as receptor for this virus, ACE-2 protein recognize receptor binding domain on virus spike protein. After recognition and attachment, virus enter into host cell via two type of pathway.

The first pathway SARS CoV-2 follow to enter the host cell is enocytosis and uptake of the virus in endosomes. Host’s pH dependent cystein protease cathepsin L. cleave the receptor attached spike protein, when this receptor attached spike protein gets activated introduce a conformational change and the later fusion of viral envelope with the endosomes will occurs.

In second mechanism, the SARS CoV-2 can enter the host cell directly by proteolytic cleavage of the receptor attached spike protein by the host’s TMPRSS2 or TMPRSS11D serine protease activation of C-terminal part of the spike protein triggers the fusion of the viral envelope with host cell membrane by introducing conformation change.

After entry translation, as well as replication of viral genome takes place, and these particle assemble into several new virus & librated by exocytosis to infect more cells.

Refrence:-

Biotekzone.blogspot.com