Viral structure Flashcards
what are the four main characteristics of the viral structure ?
- Acellular particles that would nit surive outside the host
- A single complete viral cell (Virion)
- Simple organisation and structure
- Contains one type of nucleic acid (usually dan or rna
- Unable to reproduce outside of the hosts cell
How does dan nucleic acid occur inside cells ?
single stranded (linear stranded or circular) or double stranded (linear double stranded e.g herpes
How can rna occur in viral nucleic acids ?
single stranded or double stranded.
What is the capsid ?
A shell of proteins that surround the nucleic acid (genetic information).
If a virus contain a envelope what does it consist of ?
Created from host derived glycolipids.
What are the 3 main types of symmetry found in viruses ?
Complex, icosahedral and helical.
How many faces and vertices do icohedrons have and what ratio of symmetry do they show ?
20 faces 12 vertices. 5:3:2 symmetry.
whats the difference in shape and number of hexon and penton capsomeres ?
Hexons are found on the edges and faces of the capsid where as pentons are found on the vertices. There is always 12 pentons and the number of hexons can vary.
What equation can be used to calculate the total number of capsomeres using the triangulation factor?
C=10T+2
Name a virus that shows helical structure and how the proteins are arranged in the capsid.
The Tobacco Mosaic Virus (TMV). The proteins show rotational symmetry. They are arranged around the circumference in a helical manner.
Name a virus with a complex structure.
Pox virus.
Whats meant when a prion has binal structure ?
when they have a icosahedral head but a helical sheath.
What is a viral envelope made of ?
Phospholipid bi layer with embedded proteins.
