What are the 3 types of viruses?
The Three Major Types of Computer VirusesMacro viruses – These are the largest of the three virus types.
They use built-in programming scripts in such applications as Microsoft Excel and Microsoft Word to automate the tasks.
Boot record infectors – These viruses are known also as boot viruses or system viruses.
File infectors – These viruses target ..
What is the smallest virus?
AAV is the smallest DNA virus with an average size of 20 nm. AAV was discovered in 1965 as a defective contaminating virus in an adenovirus stock (Atchison et al., 1965).
Is a virus a cell?
Because they can’t reproduce by themselves (without a host), viruses are not considered living. Nor do viruses have cells: they’re very small, much smaller than the cells of living things, and are basically just packages of nucleic acid and protein.
What are the examples of DNA viruses?
Examples include Mimivirus, which infects amoebae and has the largest genome (~1.2 Mb); viruses that infect algae (phycodnaviruses) and have genomes up to ~560 kb; viruses that infect bacteria and have genomes up to ~670 kb; and White spot shrimp virus (WSSV), which has a genome of ~305 kb.
How many DNA viruses are there?
There are six different DNA virus families that infect and may cause significant disease in humans. These can be further subdivided into those with “small” DNA genomes or “large” DNA genomes.
What is a DNA based virus?
A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. … DNA viruses are ubiquitous worldwide, especially in marine environments where they form an important part of marine ecosystems, and infect both prokaryotes and eukaryotes.
What are DNA and RNA viruses?
DNA viruses contain usually double‐stranded DNA (dsDNA) and rarely single‐stranded DNA (ssDNA). These viruses replicate using DNA‐dependent DNA polymerase. RNA viruses have typically ssRNA, but may also contain dsRNA. ssRNA viruses can be further grouped as positive‐sense (ssRNA(+)) or negative‐sense (ssRNA(−)).
What are the 3 shapes of viruses?
In general, the shapes of viruses are classified into four groups: filamentous, isometric (or icosahedral), enveloped, and head and tail. Filamentous viruses are long and cylindrical. Many plant viruses are filamentous, including TMV (tobacco mosaic virus).
What gives a virus its shape?
The amount and arrangement of the proteins and nucleic acid of viruses determine their size and shape. The nucleic acid and proteins of each class of viruses assemble themselves into a structure called a nucleoprotein, or nucleocapsid.