Viral genomes exhibit extraordinary diversity with respect to nucleic acid type, size, complexity, and the information transfer pathways they follow. Thus, viral nucleic acids can be DNA or RNA, double-stranded or single-stranded, monopartite or multipartite, linear or circular, as short as 2 kb or up to 2500 kb long.
What are three characteristics of viral genomes that may vary among viruses?
Viral genomes may vary in the type of genetic material (DNA or RNA) and its organization (single- or double-stranded, linear or circular, and segmented or non-segmented). In some viruses, additional proteins needed for replication are associated directly with the genome or contained within the viral capsid.
What are the four types of viral genomes?
RNA viral genomes are broadly divided into double stranded RNA, positive and negative strand single stranded RNAs, monopartite and multipartite RNA viruses.
What is the function of the viral genome?
The main function of the virion is to deliver its DNA or RNA genome into the host cell so that the genome can be expressed (transcribed and translated) by the host cell. The viral genome, often with associated basic proteins, is packaged inside a symmetric protein capsid.
What all viruses have in common?
All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form, outside the cell, a virus particle is called a virion.
What are three living characteristics of a virus?
Living characteristics of viruses include the ability to reproduce – but only in living host cells – and the ability to mutate.
What are the four properties that define a virus?
General Properties of Viruses
- Nucleic acid -contains 3-400 genes. Deoxyribonucleic Acid (DNA) -unique features. …
- Capsid -The capsid accounts for most of the virion mass. …
- Envelope -this is an amorphous structure composed of lipid, protein and carbohydrate which lies to the outside of the capsid. …
What characteristic of living cells do viruses lack?
Because viruses do not consist of cells, they also lack cell membranes, cytoplasm, ribosomes, and other cell organelles. Without these structures, they are unable to make proteins or even reproduce on their own. Instead, they must depend on a host cell to synthesize their proteins and to make copies of themselves.
Do viruses meet the characteristics of life?
Viruses do, however, show some characteristics of living things. They are made of proteins and glycoproteins like cells are. They contain genetic information needed to produce more viruses in the form of DNA or RNA. They evolve to adapt to their hosts.