Viruses

Question 1

What is a virion

Answer 1

A mature virus particle that is usually dna or rna (never both) genome in a protein coating
Some can have lipid envelope

Question 2

True or false: viruses can replicate outside the host

Answer 2

False they utilize host cell machinery to replicate

Question 3

What is a capsid also known as

Answer 3

Protomers which are proteins that make up the capsid

Question 4

What is a spike also known as

Answer 4

Peplomer which are virus proteins used for attachment

Question 5

How do envelope viruses work

Answer 5

Steal from host cell
They are harder for immune system to recognize because it’s cloaked and tricks immune system into thinking they belong

Question 6

What is the shape of a virus

Answer 6

Helical
The same protein or protomer coils wraps around helical piece of rna

Question 7

What are envelopes and how are they made

Answer 7

Double lipid membrane
Made based on how the virus replicates

Question 8

What is a butting event

Answer 8

Capsid buds out to leave and coats itself in plasma membrane which means it gets an envelope

Question 9

What did the international committee on taxonomy of viruses discover (slide 8)

Answer 9

Ask Annabelle

Question 10

What is the Baltimore system

Answer 10

Based on genome and the process used for making viral mRNA

Question 11

How does dsDNA become a protein

Answer 11

Is becomes mRNA then protein

Question 12

How does ssDNA become a protein

Answer 12

Becomes a dsDNA then an mRNA and finally protein

Question 13

How does a dsRNA become a protein

Answer 13

Goes straight to mRNA and then protein

Question 14

How does a positive ssRNA become a protein

Answer 14

It can either turn into a negative strand then go to mRNA and finally protein or it will go straight to mRNA and then protein

Question 15

How does a negative ssRNA become a protein

Answer 15

Becomes mRNA and then protein

Question 16

How does a positive ssRNA retrovirus become a protein

Answer 16

It uses reverse transcriptase to go back to ssdna then dsDNA then to mRNA and then protein

Question 17

How does a reverse transcribing dsDNA become a protein

Answer 17

It turns into an rna strand and then back to dsDNA then to mRNA and then protein

Question 18

What are the five steps of replication and reproduction in viruses

Answer 18

Attachment
Entry
Synthesis
Assembly
Release

Question 19

What does phage mean

Answer 19

Virus that infects bacteria

Question 20

What is the virulent phage also known as and what is the result

Answer 20

The lytic cycle which results in a burst of bacterium due to growth and release of new phage

Question 21

What is the total pathway of a lytic cell

Answer 21

Virus binds to special binding sight and injects genetic info into host cell which redirects machinery to focus on virus
Then cell lyses and releases the new phages which bind onto new cells
The only option for lyric cycle is cell death

Question 22

What is another name for temperate phage and what is the result

Answer 22

Lysogenic cycle which is when a phage genome integrates itself into host chromosome

Question 23

What is a lysogenic conversion

Answer 23

Lysogeny results in new phenotype

Question 24

What is the lysogenic pathway

Answer 24

Virus binds to special site using receptors which injects genetic info into host cell and redirects cell machinery to focus on virus
The phage dna is then integrated into the host chromosome and copied when cell divides
Exposure to stress such as uv light triggers excision from host chromosome

Question 25

What is a prophage

Answer 25

Name of genome that integrates itself into host cell genome and doesn’t cause cell death

Question 26

How does adsorption of a virus work

Answer 26

Recognizes and binds receptors The receptor is essentially a tropism For example T4 likes the LPS of ecoli

Question 27

What is a tropism in viruses

Answer 27

When a virus only binds to a specific type of cell or region because of the specific receptor it has

Question 28

How does entry work in viruses

Answer 28

Acts as syringe Brings lysozymes which break down peptidoglycan and penetrates then injects genetic material into host

Question 29

What do early mRNAs do in viruses

Answer 29

Commandeer host cell machinery and degrade host dna

Question 30

What do late mRNAs do in viruses

Answer 30

Phage structural proteins Assist with phage assembly Cell lysis

Question 31

How does release work of a virus

Answer 31

Lysis of a cell which releases newly assembled viruses

Question 32

What is phage therapy

Answer 32

Using phages to clear bacterial infection There are restrictions of phages to particular species and strains

Question 33

How does a virus inject into a cell

Answer 33

Tail fiber contracts and baseplate contacts the membrane The sheath contracts and the lysozyme dissolves peptidoglycan and dna is injected

Question 34

What does it mean when a virus enters a cell via fusion

Answer 34

Entry of enveloped virus by fusing with the plasma membrane

Question 35

How does endocytosis work in viruses

Answer 35

Spikes brought to receptors on plasma membrane which then surrounds the whole virus cell and then it becomes an endosome It is the entry of an enveloped virus by endocytosis

Question 36

How does entry of a non enveloped virus work

Answer 36

Virus doesn’t have envelope so the capsids bind to plasma membrane of cell and it eventually surrounds the virus Ask Annabelle I’m not sure if this is right

Question 37

What are the two release techniques and what are they used for

Answer 37

Lysis is a mechanism for naked viruses Budding is for enveloped viruses

Question 38

What is latency

Answer 38

Time of infection to the time you show symptoms

Question 39

What are the outcomes of a virus entering a cell

Answer 39

Rapid multiplication which ends in lytic cell (usually acute infection) Viral components are present but don’t harm the host which is essentially period of dormancy (latent infection) Slow release of virus without cel death (chronic infection) Integration of genome into host chromosome; has capability of causing cancer depending on insertion of genome

Question 40

What is influenza

Answer 40

Viral infection, prevalent in winter season Respiratory tract infection Segmented negative sense rna

Question 41

What are the two outer surface proteins of influenza

Answer 41

Hemagglutinin and neuraminidase

Question 42

What are the three main influenza A subtypes that inject humans and what is the most prevalent type of influenza

Answer 42

H1N1, H2N2, H3N2 Type A

Question 43

What is the average mortality of influenza

Answer 43

2 percent

Question 44

How many types of viruses does influenza have

Answer 44

3: A, B, C They all have different nucleoproteins These three types are due to structural differences

Question 45

What is hemagglutinin

Answer 45

Involved in binding to sialic acid on respiratory mucosa Binding sites used to anchor virus to host cells Agglutination of red blood cells

Question 46

What is antigenic drift

Answer 46

Slight change to protein that benefits virus so it’s retained

Question 47

What is agglutination of rbc

Answer 47

Clumping of rbc

Question 48

What is neuraminidase

Answer 48

Breaks down protective mucous coating Assists in viral budding and keeps viruses from sticking together Participates in host cell fusion

Question 49

What is a cytokine storm

Answer 49

Strong immune response that results in death because so many of your cells have died

Question 50

How can you treat the Spanish flu

Answer 50

Aspirin which you can’t give to children because it will cause autoimmune response in heart Flumist Adamantane which blocks neuramidase