What is the general structure of a virus quizlet?
Describe the general structure of a virus. Nucleic acid (DNA or RNA) surrounded by a protein coat called a capsid. Virus may be naked or enveloped.
What is the structure and composition of a virus?
Viral Structure. In the simpler viruses the virion consists of a single molecule of nucleic acid surrounded by a protein coat, the capsid; the capsid and its enclosed nucleic acid together constitute the nucleocapsid. 1-1A ), and in other viruses the capsid is surrounded by a lipoprotein envelope (Fig. 1-1D).
What are the general characteristics of viruses?
- Non living structures.
- 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.
How do viruses act?
Viruses initially stick to cell membranes through interactions unrelated to fusion proteins. The virus surfs along the fluid surface of the cell and eventually the viral fusion proteins bind to receptor molecules on the cell membrane (4). If only binding occurred, the two membranes would remain distinct.
Does a virus have DNA?
Most viruses have either RNA or DNA as their genetic material. The nucleic acid may be single- or double-stranded. The entire infectious virus particle, called a virion, consists of the nucleic acid and an outer shell of protein. The simplest viruses contain only enough RNA or DNA to encode four proteins.
How do viruses evolve so quickly?
Viruses undergo evolution and natural selection, just like cell-based life, and most of them evolve rapidly. When two viruses infect a cell at the same time, they may swap genetic material to make new, “mixed” viruses with unique properties. For example, flu strains can arise this way.
What 2 components do all viruses contain?
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.