What are the 2 main parts that make up all viruses?

What are the 2 main parts that make up all viruses?

The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.

What makes a virus a virus?

A virus is essentially a bundle of genetic code, either in the form of DNA or RNA, encased in a protein coating, known as a capsid. But, unlike bacteria, a virus cannot reproduce itself without invading a host cell because it lacks some of the crucial machinery for metabolism and replication.

What are the 2 characteristics of viruses?


  • Non living structures.
  • Non-cellular.
  • Contain a protein coat called the capsid.
  • Have a nucleic acid core containing DNA or RNA (one or the other – not both)
  • Capable of reproducing only when inside a HOST cell.

What purpose do viruses serve?

Because they are constantly replicating and mutating, viruses also hold a massive repository of that other organisms can incorporate. Viruses replicate by inserting themselves into host cells and hijacking their replication tools.

Do viruses fossilize?

In general, viruses cannot leave behind physical fossils, therefore indirect evidence is used to reconstruct the past. For example, viruses can cause evolution of their hosts, and the signatures of that evolution can be found and interpreted in the present day.

How long have viruses existed?

They existed 3.5 billion years before humans evolved on Earth. They’re neither dead nor alive. Their genetic material is embedded in our own DNA, constituting close to 10% of the human genome.

Do viruses respond to stimuli?

In isolation, viruses and bacteriophages show none of the expected signs of life. They do not respond to stimuli, they do not grow, they do not do any of the things we normally associate with life. Strictly speaking, they should not be considered as “living” organisms at all.

What percentage of the human genome is made of viral fossils?

Eight percent of the human genome is derived from over 100,000 retroviral fossils [1], many of which are present in all simian primates that last shared a common ancestor over 30 million years ago [2].