Virus Structure and Function Flashcards Preview

DD Test 3 > Virus Structure and Function > Flashcards

Flashcards in Virus Structure and Function Deck (21):
1

Define the basic properties of viruses.

Not alive
Submicroscopic, obligate intracellular parasites
Directs synthesis in host cells

2

List the strategies viruses employ for survival.

Housing genetic data in capsids
Genome contains all the infor to initate and complete an infectious cycle
Establish a relationship with the host lethally or benignly

3

Describe two means of classifying viruses.

Classical system, where viruses are grouped according to their shared physical properties

Baltimore System- based on the central dogma of DNA->RNA->Protein (aka how they produce mRNA)

4

Describe the seven basic virus genomes

dsDNA, gapped circular dsDNA, ssDNA, dsRNA, ss+RNA, ss-RNA, ss+RNA w/ DNA intermediate

5

dsDNA

Transcription of the (-) DNA strand as a template, using host RNA polymerase

Can be nuclear (more dependent) or cytoplasmic (more independent)

6

Gapped Circular dsDNA

Transcription of the (-) DNA strand as a template, using host RNA polymerase

Uses viral encoded reverse transcriptase to copy genome from viral mRNAs

7

ssDNA

Transcription of the (-) DNA strand as a template, using host RNA polymerase

Nuclear replication, involving formation of dsDNA as template

8

dsRNA

Uses RNA dependent RNA polymerase

9

ss+RNA

Uses RNA dependent RNA polymerase
Can be translated directly by cellular ribosomes
Amplification mediated by RpRp

10

ss-RNA

Packes RpRp with the virus

11

ss+RNA w/ DNA intermediates

Retroviruses, changing their ssRNA to dsDNA using reverse transcriptase. They then integrate into host genome

12

Capsid Types

Icosahedral and Helical

13

Envelope

Lipid bilayers with viral glycoproteins

Do not necessarily kill the host

14

Eclipse period

Time between 0-12hours after viral absorption where no infectious virus is detectable inside or outside of the cell

15

Latent period

The time between initiation of infection and release of new virus particles

16

Viral Attachment

VIrus attaches to target cell

17

Entry

Virus penetrates the cell and is energy dependent
Endocytosis or envelope fusion

18

Uncoating

Viral capsid is partially/completely removed and genome is exposed

19

Genome Replication

Exact copies are produced for progeny virions

20

Assembly

Either capsid can be made around genome, or genome is fed into preformed capsids

Can lead to visual inclusions

21

Egress

Exit. Naked viruses lyse the cell, enveloped viruses bud