Viruses 2 Flashcards Preview

Microbiology > Viruses 2 > Flashcards

Flashcards in Viruses 2 Deck (44)
Loading flashcards...
1

importance of viruses of prokaryotes

they can be used to kill bacteria - bacteriophages

2

genome of viruses of prokaryotes

majority are double stranded

3

how do we detect viruses

biochemical (enzymatic assays and PCR and NA hybridization), serological (IF, IP, IB, ELISA, RIA), electron microscopy

4

do you detect viruses and virions the same way

no

5

how do you estimate how well virion are doing

if it makes 1% of what it is supposed to make - quantity over quality

6

what are plaque assays based on

based on CPEs (growth lacking where they grow)

used in bacterial cells to demonstrate viable phage numbers, used to detect total virions in mammalian cells, viral particles must be viable

point here is that it is only used to detect virions which are viable viruses

7

how are viruses used as tools?

• Molecular and cellular biology
– Manipulate systems to investigate function of cells
• Genetics
– Have contributed to understanding of DNA replication, transcription, translation, transport
• Gene therapy
• Immunology
– Understanding our immune system

8

do viruses have protein synthesis machinery and division by binary fission

no -- they use host's machinery system

9

where does protein synthesis for virus occur

in the cytoplasm of the host cell

10

what are virioids and where are they usually found

infectious, subviral particles

found in plant diseases

11

type of genome in viroids

small circular single stranded DNA

12

do viroids encode protein

no but they replicate autonomously

13

what are pseudovirons

they contain non viral DNA but are infectious and do not replicate

14

what are defective virus/satellites

they are viral kind of viruses that cannot encode capsid protein so they depend on helper viruses for their propagation(replicating), ssRNA, and DNA

15

example of a defective virus

Hep D

16

what does Hep D (delta agent) use as its helper

Hep B

17

why is Hep D considered "viroid-like"

because it does code for its own protein

18

are prions viruses

no

19

properties of prions

proteinaceous and infectious but no NA

20

where do virophages grow

only in a strain of the mimivirus within the infected amoeba -- that can infect us

21

what is the first virophage discovered and describe it

sputnik: an 18 Kb circular double-stranded DNA, icosahedral virus

22

what do virus need to do to propagate (to replicate)

– Infect an appropriate host cell
– Use the host cell to generate more of itself
– Get out of the host cell to do it all over again

23

what are the phases of viral life cycle

• Eclipse phase - infectious virus cannot be seen or recovered from infected cells
• Maturation (there is a lot of it)
• Latent phase - progeny virus accumulates intracellularly but it hasn't been released yet - ends when free virus is released

24

when does latent period end

when it becomes extracellular aka when the free virus is released

25

what are the five main stages of virus life

1) attachment (adsorption)
2) penetration (injection)
3) protein and nucleic acid synthesis
4) assembly and packaging
5) virion release

26

in the influenza virus, where does transcription and replication occur

nucleus

27

how does influenza virus get its envelope

by budding out of the cell after its assembly

28

what type of mechanism occurs in adsorption/attachment stage of virus life cycle

specific and non specific

29

what is the difference between susceptibility and permissibility

susceptibility - does the cell have the receptor required for the VAP (viral attachment protein) to attach so that the virus can get into the cell

permissibility - does the cell have the machinery needed for the virus to be able to replicate

30

what determine susceptibility and what are these structures made of

receptors - made of protein, carb, or lipid