Viruses Part 2 Flashcards
Can we grow viruses on agar plates?why?
No, because it needs live hosts cells
( on an agar it just nutrients )
What are viruses ?
Obligate intracellular parasites
Where do we culture viruses?
Embryonated eggs
What is the most common way to culture viruses?
Live cells
What type of cells are the best used when trying to culture a virus ? And in what?
Transformed cells ( cancer cells ) in tissue culture
Why are transformed cells, cancer cells, the best type of cell to use when trying to culture viruses?
Because they don’t die
What’s also another name for transformed cells, that isn’t cancer cells? Why do we call that?
Continuous immortal cell lives
( cause they don’t die as fast, and we have every type of cancer cell in any tissue from our body )
What is the hardest culture to grow viruses on? Or use them on?
Animals
What was the first/ and most famous cell line that we used on tissue culture?
HeLa cells
Who was the person name associated with HeLa cells?
Henrietta lacks
How did HeLA cells help us?
To help develop cancer research method that tested if it was cancer or not
What are the 3 cultivation of viruses?
Bacteriophage
Plant viruses
Animal viruses
How does bacteriophage work in cultivation of viruses?
Suspension or solid media to form plaques
How does plant viruses work in cultivation of viruses? (2)
Whole plant or plant cell culture
How does animal viruses work for cultivation of viruses?(3)
Whole animal
Embryonated eggs
Animal cell culture
What are the 3 lines that we can use to culture animal viruses?
Primary cell lines
Diploid cell lines
Continuous cell lines
What are primary cell lines? ( how long does it last )
Derived from tissues by enzymes
( usually die after couple of generations )
What are diploid cell lines? ( how long does it last )
Derived from human embryos
( multiply for about 50-100 generation then die )
What are continuous cell lines? ( how long do they last )
Immoral lines derived from transformed or cancerous cells
( multiplies indefinitely & are immoral )
What are continuous cell lines mainly used in?
Propagation of viruses
( the breeding of viruses )
What do viral genes code for?
Capsid proteins and some enzymes needed for replication
Why does viruses need to use host cells enezymes?(3)
They need it for
Protein synthesis
Energy production
Ribosomes
Can viruses replication occur outside the cell?
NO!
( only replicate inside the cell )
What happens when the viruses invades the host cells? (2)
They control metabolic and replicating machinery
( pretty much makes viral proteins & nucleic acid for new viral particles )
Do viruses have ribosomes?
No
Do viruses have some enzymes?
Yes, very little
Do viruses need a host to replicate?
Yes
What are the 3 animal virus cycles?
Lytic
Lysogenic
Transforming
What’s the difference between Lytic and lysogenic?
Lytic doesn’t go into the host chromosome & instead just uses the cell to make progeny ( babies ) then releases them out, as virons & cell dies
Lysogenic goes into the host chromosome, called prophage, binary fission, has a prophage every time when divides and goes into Lytic cycle
What does prophage mean?
Bacteriophage into host Chromosome
What does progeny mean?
Viruses babies
What does virons mean?
Complete infectious particle
What is a virus that performs Lytic cycle?
Influenza
What is a virus that performs lysogenic cycle?
Retrovirus
What is transforming interaction?
Infection of the cell & changes into cancer cell
What is a virus that does transforming interaction?
HPV ( human papilloma virus ) &
Hepatitis B
What is the 6 lytic viral replication cycle?
- Attachment or absorption
- Penetration or entry
- Uncoating
- Binary fission
- Maturation or assumbly
- Release
What is the 7 lysogenic viral replication of animal viruses?
- Attachment
- Penetration
- Uncoating
- Integrating into the cell
- Biosynthesis
- Maturation
- Release
First it must ___ to the host
Then it must ___through the cell membrane
___itself it order to release its nucleic acid for replication, to make ____
Once it’s release, we undergo ____
In which we create__&__ for our new virus
Then our new ___ start to ____
Then we ___ them as virions
- Attach
- Penetrate
- Uncoats (It’s capsid)
- Proteins
- Biosynthesis
- New proteins & new nucleic acid
- Progeny ( virus’s babies )
- Mature
- Release
If a pathogen can not ____
It can not ___
If it can not infect it can not cause ___
- Attach
- Infect
- Disease
What makes DNA & RNA viruses different in the replicative cycle ?
The biosynthesis step
( the nucleic acids are different )
In order for attachment to occur, what must happened?
Specific receptors just match the surface of the host cell
( lock and key )
Why is it only some cells that are infect with the viruses?
Because of the lock and key, must have specific receptors to infect
Where are these receptors of enveloped viruses?
On their envelope spikes
Where are these receptors on a naked virus?
Capsid
For influenza, what is the receptor used for attachment ?
HA - hemaagluttanin
If the virus can not penetrate the cell membrane will it infect?
Nope
Does the virus have to penetrate the cell membrane to infect?
Yes
What are the 2 ways of penetration?
Endocytosis
Fusion of envelope
What is endocytosis?
Cell membrane makes a vesicle & brings the virus inside host cytoplasm
Can naked viruses perform endocytosis?
Yes
Can enveloped viruses perform endocytosis ?
Yes
What is fusion penetration?
Enveloped viruses fuse with cell membrane
Why is it only enveloped viruses that can fuse with cell membrane?
Because they are both made of phospholipids
Can naked viruses perform fusion with cell membrane ?
No
What is uncoating?
Separation of nucleic acid from the protein capsid coat
How does the uncoating work for the virus (2)?
Host lysosomal enzymes
Or
Configuration changes in capsid
What are viral capsid made of?
Proteins
What are viral enveloped made up of?
Phospholipids
What’s another name for capsid?
Nucleiocapsid
What’s is the 4th step ? Breaking of? (3)
Biosynthesis
Breaking this nucloicapsid to make new proteins & new nucleic acids
Does the virus depend on the host cell for biosynthesis?why?
Yes because it has all the enzymes, ribosomes and stuff to make more progeny
Where do dna viruses replicate in biosynthesis ?
Nucleus
What is the expection of dna viruses that don’t replicate in the nucleus?
( name the family and virus )
Poxvirdae ( small pox )
What is the enzyme used for dna viruses replication in biosynthesis?
Dna dependent dna polymerase
Where do rna viruses replicate in biosynthesis?
Cytoplasm
What are the 2 expect of rna viruses that don’t replicate in the cytoplasm for biosynthesis ? ( family name and virus )
Retroviridae ( HIV )
Orthomyxoviridae ( influenza )
What is the enzyme used to make rna replication occur in biosynthesis?
Rna dependent rna polymerase
Do cells have rna dependent rna polymerase enzyme ?
No
( cells don’t make rna, they copy it from dna, transcription )
What is happening in maturation or assembly?(2)
Capsomers into capsid
New nucleic acids & proteins to form new virions
What are the 2 ways that viruses can be released?
Lysing the cell
Budding
What do naked viruses use? Budding or lysing the cell?
Lysing the cell
What does Lysing the cell mean?
Host cell dies
How many virions come out when a cell is lysis?
50-200
How do envelope viruses release out of a cell?
Budding
Where do envelope viruses get their envelopes?
Host cell membrane
( phosphophild bilayer )
True or false ? Envelope viruses manufacture the envelope inside the cell before they get released? ( why? )
False
- because when budding they get their Envelope from host cell membrane, they don’t make it
What are retroviruses genome?
RNA
Are retroviruses lysogenic?
Yes, they integrate into the host Chromosomes
What makes retroviruses so speical?
They reverse transcription
RNA -> DNA -> integrates
What is the enzyme that allows retroviruses to make rna to dna ?
Reverse transcriptase
If you had to name for the enzyme, reverse transcriptase, what would it be?
RNA dependent DNA polymerase
What are the 7 steps of retrovirus ?
- Attachment to host
- Penetration by fusion
- Uncoat
- Biosynthesis ( RNA -> DNA )
- Provirus are made
- Assembly/maturation
- Release —> budding
What is happening in biosynthesis of retroviruses ? (4)
Reverse transcriptase
(RNA->DNA)
DNA enter nucleus
Dna stays in host genome ( provirus )
Makes proteins
What is a provirus ?
Viruses that’s part of the host Chromosome
What is the difference between nucleicapsid and provirus ?
Capsid that helps protect the nucleic acid in viruses
Provirus is the viruses inside host chromosomes
How many people have been cured from HIV?
Like 2-3 people ( kinda crazy )
How many people have been infected with HIV ?
80 million
Every single time the retrovirus divides will it have the provirus in it?
Yes, every single time
What’s the whole purpose of a virus?
To make baby viruses ( progeny )
How do retro viruses people get cured? ( just some extra information )
Some people are born with a genetic mutation, in one of their receptors aren’t there, and are healthy.
( pretty much genetically resistant to hiv )
Who was the first person cured of hiv ?
Timothee brown
Do viruses become latent? And which one?
Yes, Herpesvirdiae
Are all herpes viruses the pro-type for latent viruses?
Yes
Can some viruses cause cancer in humans ? Which one? (3)
HPV ( human papilloma virus )
( cervical cancer )
Hepatitis B
( liver cancer )
EBV ( Epstein Barr virus )
( burkitt lymphoma )
What is the name for viruses that cause cancer ?
( onco what )
Oncogenic
Can viruses that lay latent cause disease if it isn’t activated ?
No
Can viruses cause disease if it becomes activated?
Yes
What are 2 examples of viruses that are latented, and become disease if activated?
Herpes ( cold sores & gential herpes )
Chicken pox -> shingles
What is HTLV & HTLV2 ? And causes?
Cancer in humans
Human T cell lymphogrophic virus
What does onco mean?
Tumor
What does oncogene mean?
Tumor gene
What does oncogenic virus mean?
A virus that promotes tumor formation
Does oncogenic virus integrate into the host Chromosome?
Yes, because it causes transformation of cells ( cancer cells )
HIV can worsen, and go into?
AIDS
What does aids stand for?
Acquired immunodeficiency syndrome
