intro to virology

Question 1

characteristics of a virus

Answer 1

very small. non circular, obligate intracellular parasite

Question 2

what is a virus particle contained in

Answer 2

nucleic acid (DNA or RNA), protein shell (capsid), – sometimes lipid layer too (envelope).

Question 3

how does virus replication happen

Answer 3

virus genome directs synthesis of virus proteins and progeny virus genomes using cellular machinery.

Question 4

how does virus assembly occur

Answer 4

The virus components produced by the host cell are assembled into progeny virus particles.

Question 5

do viruses undergo self replication

Answer 5

no

Question 6

do virus particles have ribosomes

Answer 6

no

Question 7

what is the structure of a virus

Answer 7

composed of nucleic acid genome, protein genome, protein caspid and sometimes a lipid envelope associated with virus proteins

Question 8

what is a key difference between some viruses

Answer 8

wither they have a lipid envelope or not

Question 9

what are the main components of the covid virus

Answer 9

membrane, envelope, nucleocapsid, RNA, glycoproteins, Haemaglutin-esterase dimer, spike (essential for entry to host)

Question 10

can viruses contain DNA or RNA

Answer 10

they can contain either as their genomes can vary extremely

Question 11

what is the purpose of a protein caspid

Answer 11

protects genome from environment, delivers genome to the cell

Question 12

what is a virus envelope

Answer 12

the envelope consists of a lipid bilayer from the host cell containing viral proteins

Question 13

what are the 5 main steps in viral growth

Answer 13

attachment, entry, uncoating, synthesis of viral components, assembly and release

Question 14

what system do viruses enter the host by

Answer 14

respiratory, GI, urogenitary, blood

Question 15

which ways can viruses enter through the respiratory tract

Answer 15

inhalation and touch, sexual (upper respiratory)

Question 16

which ways can viruses enter through the GI tract

Answer 16

ingestion and inhalation

Question 17

which way can viruses enter the urogenitary tract

Answer 17

sexual transmission

Question 18

how can viral particles get into the blood stream

Answer 18

vertical (childbirth), needles, insect vector

Question 19

what are the 3 mechanisms of spread within host

Answer 19

localised (stays at site), neutral (herpes), hematogenous (in blood)

Question 20

example of a localised spread virus

Answer 20

rhinovirus

Question 21

example of a neutral spread virus

Answer 21

herpes simplex virus

Question 22

example of a hematogenous spread virus

Answer 22

HIV

Question 23

what can a virus cause in the host cells

Answer 23

induce apoptosis, lysis of infected cells by immune cells and inflammation

Question 24

how are viruses dependant on a host for survival

Answer 24

• Viruses are heavily dependent on the host cell for their replication.
• Viruses can only replicate in cells that have the right properties for that virus.
• in many case impact on host is via impairing the function of specific systems

Question 25

what is the simple immune response to infection

Answer 25

- Neutralising antibodies (igG and igM) - Cytotoxic T cell response (promote destruction of infected cell)

Question 26

what is the benefit of a immune response in the host

Answer 26

- Adaptive immune response can prevent entry, mark virions for destruction & destroy infected cells

Question 27

what tests can be used to identify viral infections

Answer 27

- PCR * qPCR * Loop-mediated isothermal amplification (LAMP)

Question 28

ways to prevent viral infections

Answer 28

PPE, isolation and quarantine, harvest antibodies from donor to use, anti-viral drug targets, vaccines