Viruses Flashcards
Structure of COVID-19
spherical with spike proteins
how do COVID-19nmRNA vaccines work
- mRNA that codes for covid-19 spike proteins are encapsulated into “lipid nanoparticles”
- After injection, nanoparticles fuse with human cell membranes releasing mRNA into cells where translated into spike proteins
- spike proteins are desplayed on cells causing immune response
mRNA -> spike proteins
NOT infected with the virus - make our own spike proteins
J&J vaccine is what type
viral vector vaccine
how do viral vector vaccine works
- DNA copy of genes encoding spike proteins are incorperated into the genome of a harmless Adenovirus
- after injection Adenovirus deliver virual DNA to nucleus where it is transcribed into mRNA
- mRNA is translated into spike protein and displayed causing immune response
DNA -> mRNA -> spike protein
Parasitic Particles
Viruses, Viroids, Prions
How many viruses for every bacterial cell
10 viruses for 1 bacterial cells
virus definition
non-cellular particle capable of infecting a host cell where it reproduces (no ribosomes, cant make own proteins) - dependent on host cell
Viruses consist of
DNA or RNA (not both) enclosed in a coat of protein (and sometimes a membrane envelope)
Bacteriophage
viruses that infect bacteria
Two types of viruses based on their coat
naked (capsid only) and enveloped
Animal viruses characteristic
- most are eveloped
- some are naked - naked polyhedral virus in common cold (Rhinovirus)
Bacteriophages: naked or envelope
always naked (no membrane)
Bacteriophages are important for these 3 things
- genetic transfer (transduction)
- Control of bacteria in nature
- Transduction can cause bacteria to become pathogens
Also very important in nutrient cycling since releasing things back into environment
What occurs during lysogenic cycles vs lytic cycles
Lysogenic: viral genome incorperated into chromosome of host cell - duplicated thru dinary fisson
Lytic: viruses attack cell and take over mechinary and kill cell
what is transduction
Transduction is the process by which foreign DNA is introduced into a cell by a virus or viral vector.
What do eukaryotic viruses and archaeal virsuses have in common
- both can be enveloped OR naked
Viroids
RNA molecules that infect plant
* no protein capsid or membrane
* potato spindle tuber viroid
Prions
proteins that infect animals
* no nucelic acid component
* abnormal structure that alters conformation of normal proteins
* Transmissible Spongioform Encephalopathies (TSEs) - due to holes in brain (sponges)
* all neurological disorders
Kuru
first proven prion dieseae limited to the Fore people of New Guinea
* exposure during mourning ritals
* LAck of coordination, coma, death
* Neuological
* infectionous
* now extinct
How do prions cause disease and replicate without nucleic acids?
Recruit proteins similar to themselves in the membranes of brain cells
cause normal proteins in the brain to change shape
* cause a shift in protein tertiary structure
* causes outer lining of brain cells to become rigid and cavity forming = death to brain cells and holes
SAME amino acid sequence DIFFERENT tertiary structure
Mad cow disease (BSE)
meat and bone mean (brains) fed to cows as protein supplement
- long latent period to infected cattle fed to humans
- prions are NOT destroyed by cooking , burial in soil, disinfectants = more durable than endospores
- human BSE is usually called cariant Creutzfelt-jacob disease
HIV is the ….. AIDS is the ….
HIV = disease
AIDS = virus
HIV casues AIDS
HIV is an enveloped ….
retrovirus
RNA virus!
how do retroviruses work
viral reverse transciprtase makes ssRNA into ddDNA which is incorperated into the human genome
* our machinary makes the viral mRNA
2 glycoproteins on HIV
- gp120: binds to any T cells or macrophages containing the CD4 protein
- gp41: transmembrane protein supporting gp120
HIV infection process
- HIV binds CD4 on T cells or macrophage
- envelope fuses with membrane and releases RNA into cytoplasm
- reverse transcriptase ssRNA -> dsDNA
- integarted into host chromosome, HIV DNA replicates as host DNA replciated
When is AIDS diagnosed
When an individual test positive for HIV and has either:
* <200 CD4 cells per uL blood
* presence of oppotunistic infections or atypical cancer
Oppotunisitc infection associated with AIDs
- Pneumocystis pneumonia: fungal disease
- Candidiasis
- Mycobacterium avium infection, which usually cause pneumonia
cancers associated with HIV/AIDS
- kaposi’s sarcoma
- Cervical cancers
- liver cancer
- mouth and throat
Trasnmission of AIDS
direct exposure of bloodstream to bodily fluid: mother to child, blood transfusions, intravenous drug use
unprotected sex
HAART
Highly active Anti-retroviral drugs
* blocks reverse transcription
* Protease inhibitors or Entry inhibitors
Enfurvirtide
“entry inhibitor”
