Viruses and Prions

Question 1

Virus?

Answer 1

Non-living entity that reproduce in host

Obligate intracellular parasite

Question 2

Virion?

Answer 2

Extracellular form to travel from one host to the other

Question 3

Capsid?

Answer 3

Protein shell and the viral genome –> Protects and can have many enzymes for attachment and penetration

Question 4

Envelope?

Answer 4

Outside the capsid with a phospolipid bilayer and proteins

Question 5

Virulent?

Answer 5

Lytic virus that redirect the host metabolism for production of new virions.

Question 6

Lysogenic?

Answer 6

Genome becomes a part of the host genome –> replication with host DNA.

Question 7

Viral genome?

Answer 7

DNA / RNA
Single / Double
Linear / Circular

Question 8

Single?

Answer 8

+ sense –> Base sequence is the mRNA

• sense –> Base sequence is complementary to the mRNA.

Question 9

The entry?

Answer 9

Bacteria - Only nucleic acid

Eukaryota - Entire virion

Question 10

The virus cycle?

Answer 10

A
P
S
A
R

Question 11

Attachment?

Answer 11

The receptors attaches to the cells membrane

Question 12

Penetration?

Answer 12

Changes in both the host and viral membrane and enzymes breches the layer and nucleic acid comes into the cytoplasm.

Question 13

Synthesis?

Answer 13

DNA Pol in the host or from the viral seq with prim and heli. Stops the host and starts encoding the viral. Early middle and late enzymes and sigmafactors that modifies the host RNA Pol for viral synthesis.

Question 14

Assemble?

Answer 14

Concatemer when packaged into capsids through headful packaging and the viral genome is pumped in by energy linked packing motor. Proheads expand and tail and other proteins are added.

Question 15

Release?

Answer 15

Adding the final products by spontanoeus reactions and by very late enzymes. Opens the cell by osmotic lysis.

Question 16

Latent period?

Answer 16

Ecplipse + Maturity phase

Question 17

Burst size?

Answer 17

Nr of virions relased

Question 18

Titer?

Answer 18

Concentration of virions on (l)

Question 19

Plaque?

Answer 19

Zone of cell lysis

Question 20

Circular perputation?

Answer 20

Same set of genes but in different order

Question 21

Terminally redundant?

Answer 21

DNA seq duplicates on both ends of the DNA molecule

Question 22

Modification?

Answer 22

Own DNA system –> CRISPR and endonucleases

Question 23

Temperate viruses?

Answer 23

Relationship –> lysogeny with host

Question 24

The 4 outcomes?

Answer 24

V
L
P
T

Question 25

Viral?

Answer 25

Lytic cycle

Question 26

Latent?

Answer 26

Integrated to DNA

Question 27

Persistent?

Answer 27

Budding

Question 28

Transformation

Answer 28

Tumor

Question 29

Retroviruses?

Answer 29

RNA –> DNA by Reverse transciptase

The genom to these consist of two identical single stranded +sense

Question 30

How do they work?

Answer 30

A dsDNA is cretaed by rev transcriptase
Integrase the integrate it to host DNA and it is now termed a Provirus. It is transcribed and translated together with the rest. mRNA –> 2 copies of the RNA in +sense and then into capsids enveloped and budding.

Question 31

Baltimore DNA?

Answer 31

1. Double stranded

2. SIngle stranded - all are +sense

Question 32

Baltimore RNA?

Answer 32

1. +sense - mRNA
   - sense - complementary to mRNA
2. Double stranded
3. Retroviruses
4. Eukaryotic cells - +sense

Question 33

Prion?

Answer 33

Infectous agates without RNA/DNA + Protein

Question 34

How do they work?

Answer 34

Prnp –> native PrPc (alpha helices) –> pathogenic PrPsc (beta sheets).

Enters the cell and then evolves to the pathogenic form. Forms amyloids - crystalline structures.

Question 35

Prion good?

Answer 35

Non-pathogenic - MAVS - that are a self-perpetuating form that after infection helps to recruite macrophages by releasing interferones.

Question 36

Spikes?

Answer 36

Formed on viral capsids - or - envelopes. Has the ability to bind to the host cells receptors. S-proteins that assist in attachment and in the fusion with the membrane.