Viruses

Question 1

Structure of COVID-19

Answer 1

spherical with spike proteins

Question 2

how do COVID-19nmRNA vaccines work

Answer 2

• 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

Question 3

J&J vaccine is what type

Answer 3

viral vector vaccine

Question 4

how do viral vector vaccine works

Answer 4

1. DNA copy of genes encoding spike proteins are incorperated into the genome of a harmless Adenovirus
2. after injection Adenovirus deliver virual DNA to nucleus where it is transcribed into mRNA
3. mRNA is translated into spike protein and displayed causing immune response

DNA -> mRNA -> spike protein

Question 5

Parasitic Particles

Answer 5

Viruses, Viroids, Prions

Question 6

How many viruses for every bacterial cell

Answer 6

10 viruses for 1 bacterial cells

Question 7

virus definition

Answer 7

non-cellular particle capable of infecting a host cell where it reproduces (no ribosomes, cant make own proteins) - dependent on host cell

Question 8

Viruses consist of

Answer 8

DNA or RNA (not both) enclosed in a coat of protein (and sometimes a membrane envelope)

Question 9

Bacteriophage

Answer 9

viruses that infect bacteria

Question 10

Two types of viruses based on their coat

Answer 10

naked (capsid only) and enveloped

Question 11

Animal viruses characteristic

Answer 11

• most are eveloped
• some are naked - naked polyhedral virus in common cold (Rhinovirus)

Question 12

Bacteriophages: naked or envelope

Answer 12

always naked (no membrane)

Question 13

Bacteriophages are important for these 3 things

Answer 13

• 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

Question 14

What occurs during lysogenic cycles vs lytic cycles

Answer 14

Lysogenic: viral genome incorperated into chromosome of host cell - duplicated thru dinary fisson

Lytic: viruses attack cell and take over mechinary and kill cell

Question 15

what is transduction

Answer 15

Transduction is the process by which foreign DNA is introduced into a cell by a virus or viral vector.

Question 16

What do eukaryotic viruses and archaeal virsuses have in common

Answer 16

• both can be enveloped OR naked

Question 17

Viroids

Answer 17

RNA molecules that infect plant
* no protein capsid or membrane
* potato spindle tuber viroid

Question 18

Prions

Answer 18

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

Question 19

Kuru

Answer 19

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

Question 20

How do prions cause disease and replicate without nucleic acids?

Answer 20

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

Question 21

Mad cow disease (BSE)

Answer 21

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

Question 22

HIV is the ….. AIDS is the ….

Answer 22

HIV = disease
AIDS = virus

HIV casues AIDS

Question 23

HIV is an enveloped ….

Answer 23

retrovirus

RNA virus!

Question 24

how do retroviruses work

Answer 24

viral reverse transciprtase makes ssRNA into ddDNA which is incorperated into the human genome
* our machinary makes the viral mRNA

Question 25

2 glycoproteins on HIV

Answer 25

• gp120: binds to any T cells or macrophages containing the CD4 protein
• gp41: transmembrane protein supporting gp120

Question 26

HIV infection process

Answer 26

• 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

Question 27

When is AIDS diagnosed

Answer 27

When an individual test positive for HIV and has either:
* <200 CD4 cells per uL blood
* presence of oppotunistic infections or atypical cancer

Question 28

Oppotunisitc infection associated with AIDs

Answer 28

• Pneumocystis pneumonia: fungal disease
• Candidiasis
• Mycobacterium avium infection, which usually cause pneumonia

Question 29

cancers associated with HIV/AIDS

Answer 29

• kaposi’s sarcoma
• Cervical cancers
• liver cancer
• mouth and throat

Question 30

Trasnmission of AIDS

Answer 30

direct exposure of bloodstream to bodily fluid: mother to child, blood transfusions, intravenous drug use
unprotected sex

Question 31

HAART

Answer 31

Highly active Anti-retroviral drugs
* blocks reverse transcription
* Protease inhibitors or Entry inhibitors

Question 32

Enfurvirtide

Answer 32

“entry inhibitor”