Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FunMed Microbiology > Viruses > Flashcards

Viruses Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

what do viruses do

A
  • Infect all living things
  • Come into contact with viruses through water food air
  • Viral genomes are part of our genetic material
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 7 different viral families

A
  • Paramyxoviruses 11 types
  • Adenoviruses 14 types
  • Arboviruses 8 types
  • Coronaviruses 4 types
  • Novel polyomaviruses 3 types
  • Bocaviruses 2 types
  • Herpesviruses (many new)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the most common human viruses

A
  • Herpesviruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how many viruses are known to infect humans

A
  • Greater than 200 viruses but not all of them are harmful

- Any tissue in the body can pretty much be infected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define a virus

A
  • A package of genetic information protected by a protein shell for delivery into a host cell to be expressed and replicated
  • They are obligate intracellular parasites that cannot be desicbred as either dead or alive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why is the protein shell important

A
  • Infect other cells
  • Identify cells that it can infect
  • Protect it from the innate immune system
  • Protects itself from the restriction factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

virus classification system

A
  • Kingdom
  • Phylum
  • Class order – virales
  • Family – viridae - paramyxoviridae
  • Genus – virus - morbillivirus
  • Species – measles virus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do you classify viruses

A

Baltimore classification system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

whats the defining feature feature of the Baltimore classification system

A

needs to get to mRNA

- because if you want to make proteins you have to get to mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the Baltimore classification system

A
  1. I: dsDNA viruses - (e.g. Adenoviruses, Herpesviruses, Poxviruses) double stranded DNA viruses – can make DNA
  2. II: ssDNA viruses (+)sense DNA (e.g. Parvoviruses) 0 single stranded DNA virsues – must go to double stranded
  3. III: dsRNA viruses (e.g. Reoviruses) – double stranded RNA viruses – can make mRNA directly
  4. IV: (+)ssRNA viruses - (+)sense RNA (e.g. Picornaviruses, Togaviruses, SARS-CoV) positive strand single stranded RNA – needs to go to negative then make mRNA
  5. V: (-)ssRNA viruses – (-)sense RNA (e.g. Orthomyxoviruses, Rhabdoviruses, Flu) – can be used directly
    negative single stranded RNA
  6. VI: ssRNA-RT viruses single stranded RNA - reverse trasncirbe RNA into DNA and hten make mRNA (+)sense RNA with DNA intermediate in life-cycle (e.g. Retroviruses)
  7. VII: dsDNA-RT viruses – double stranded RNA - reverse trasncirbe RNA into DNA and hten make mRNA(e.g. Hepadnaviruses)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe other classification of viruses

A
  • If they have DNA or RNA as their genetic material
  • Their genetic material is single stranded or double stranded, sing stranded RNA viruses can have either positive or negative sense RNA
  • Their capsid is shaped as helix an icosahedron or has a complex structure
  • Viruses has an envelope surrounding it or not
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what makes up the viral structure

A

glycoprotiens
envelope
caspid
nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe the envelope as viral structure

A

– derived from the host cell membranes (cell surface membrane, ER and Golgi) presence of envelope means it is easier for the virus to enter host cells this increases the infectivity, viruses that are enveloped are more prone to environmental stresses such as heat and acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the capsid as viral structure

A

made up of capsomeres, protects the DNA and RNA from nucleases and acts as antigen in virus lacking envelopes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the nucleus as viral structure

A
  • Nucleus contains the genetic material and necessary enzymes required for its translation and replication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the golgi as viral structure

A

act as attachment points to host cells, help viruses fuse with the host cell memrbane and enter the cell – glycoproteins are usually also the antigens which the immune system recognises to mount an immune response, glycoproteins can only bind to specific types of cells

17
Q

what is the information within a viral genome

A
  • Replication of viral genome
  • Assembly and packaging of the genome
  • Regulation and timing of the replication cycle
  • Modulation of host defences
  • Spread to other cells and host
18
Q

what is the functional of structural proteins

A
  • Protect the genome
  • Recognise viral nucleic acid for packaging
  • Deliver viral nucleic acid to host cells
  • Many shapes and sizes produced by evolution
19
Q

what are the different types of capsids

A
  • Helical – e.g. tobacco moascic virus, has to have a protien on the RNA in order to stay there, helcal – wraps itself regulary around the RNA
  • Icosahedral - has 20 sides, mathematically the best shape to make a capsual of that size
  • Complex
20
Q

How do capsids acquire envelopes

A

The capsid takes up the right nucleic acid that is the genome of the virus
Goes to cell surface
Protein envelope of the virus is being made in the cell
They specifically meet each other at the same place in the cell surface
Have viral glycoproteins on the outer surface – spikes
The nucleic acid recognises a specific cell type – and the envelope glycoprotein is specific to recognise the cell type – it takes it to the cell that it is required in
- Lipid envelopes are derived from cellular membranes
- Studded with surface projections, spikes or peplomers
- These are usually glycosylated by host systems prior to make them sticky

21
Q

what cells does viral replication take place in

A

susceptible and permissive

22
Q

describe the cell types associated with viral replication

A

Susceptible cell – has the functional receptor for the virus, the virus can enter the cell Resistant cell – No receptor, virus cannot get in Permissive cell – has the capacity to replicate the virus

23
Q

describe how viral infection and replication happens

A
  • Host cell membrane receptors interact with viral glycoproteins/capsids
  • Viral and host cell fusion
  • Capsids opens to let genetic material into the cell – this can happen through different mechanism such as reduced pH in lysosomes
  • Viral DNA or RNA hijack translation machinery to make viral proteins
  • DNA or RNA is replicated
  • DNA or RNA together with the capsomers form a virion (same thing as a virus)
  • Virions exit the cell through budding or cell lysis (cells that exit through budding also get an envelope from the cell surface memrbane)
24
Q

what is viral replciation divided into

A
  • Can be divided into whether they complete their replication in the cytoplasm (most RNA virsues expect retroviruses and orthyomyxoviruses plus poxviruses or whether they complete their replication in the nucleus – most DNA viruses except poxviruses plus orthmyxovirsues
  • Both compartments retroviruses such as HIV and hepadnaviruses

FunMed Microbiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions