CMB1003/L12 Intro to Virus Structure Flashcards
Are viruses single-stranded, double-stranded RNA or DNA?
They can be all of them
Why do some viruses have a capsid?
To protect the genome
What is a nucleocapsid?
The genome and the capsid protein
Why are viruses described as obligate cellular parasites?
They can only grow in appropriate host cells
What is a virion?
A purified virus particle
Give the 5 basis structural forms of viruses.
Naked isosahedral
Naked helical
Enveloped icosahedral
Enveloped helical
Complex
Give an example of a naked icosahedral virus.
Poliovirus
Give an example of a naked helical virus.
Tobacco mosaic virus
Give an example of an enveloped icosahedral virus.
Herpes
Give an example of an enveloped helical virus.
Measles
Give an example of a complex virus.
Poxvirus
Explain the mechanism by which the Oxford/Astrazeneca COVID-19 vaccine delivers the gene for COVID-19 spike protein.
Via a harmless adenovirus vector
Explain the difference between an oncolytic and an oncogenic virus.
Oncolytic viruses can be used to treat cancer
Oncogenic viruses which can cause cancer
Describe, simply, the cycle of viral infection, starting with transmission. (5)
Transmission
Entry
Primary site replication
Spread within host
Shedding
What are the 2 modes of viral transmission?
Horizontal
Vertical
Zoonosis
Describe the modes of horizontal transmission. (2)
Respiratory
Faecal-oral
Give an example of a respiratory transmitted virus.
Rhinovirus
Influenza
Measles
Coronavirus
How can droplets cause infection? (3)
Inhalation
Through conjunctiva (eyes)
Fall onto surfaces and transfer
Be dessicated
Give an example of a faecal-orally transmitted virus.
Rotaviruses
Hepatitis A
Poliovirus
Why is faecal-oral a very efficient mode of viral transmission?
Viruses can grow to high titres in faeces
Give an example of a sexually transmitted virus.
HIV/AIDS
Hepatitis B
Human Papilloma Virus (HPV)
Herpes simplex virus (HSV)
Why can HSV re-emerge when a host is vulnerable?
It lies dormant in nerves that supply the original area of infection
Give 2 less common modes of horizontal viral transmission.
In urine
Mechanical transmission
Give 2 examples of vertical infection.
Mother-to-child
Primary infection during pregnancy
Reactivation of persistent infection
Give an example of transplacental vertical transmission.
Rubella
Congenital defects
Give an example of a virus transmitted during birth.
Herpes simplex virus
Give an example of a virus transmitted from mother to child after birth.
HIV-1 in breast milk
Hepatitis B in saliva
What is a reservoir and a vector with regards to zoonosis?
Reservoir - animal in which virus replicates
Vector - animal which transmits the virus
Give 3 ways of breaking the chain of viral transmission.
Education
Barrier nursing
Quarantine/isolation/containment
