Chapter Thirteen And Fifteen Flashcards
Viruses
-parasites
-contain RNA and DNA
-have a protein coat
-spikes
Virion
A matured particles
-containing all ingredients
-virus
What makes a virion different (4)
-genome
-capsid
-envelope
-spikes on envelope
Own genome of a virion
The DNA or RNA (never both)
-determines lifecycle
Capsid of a virion
Contains genome, is a protein molecule
Capsid of virion function
-identifies virus by capsomere
-transportation
-attachment of host cell
Capsomere
What makes up capsid
Envelope of a virus is made up of
-Protein
-carbohydrates
-phospholipid on more complex ones
Spikes on envelope of virus
Found on COVID/influenza
-increases virulence
Two types of spikes
HA and NA
HA/ Hemoagglutination spikes
Attach to host cell
-strain match by spike “H1N1” or “H9N1”
The number beside H in H1N1 stands for
Each spike that has mutated once
NA spike or Neuramin
After infection, populates host cell membrane
-strain detection
HIV stands for
Human immunodeficiency virus
Four things the HIV virus contains
-RNA genome
-capsid
-envelope
-spikes
Spikes are made up of
GP (carbohydrate + protein) 41+120
Three facts about HIV
-is a retro virus
-only replicates in humans
-only kills/invalids helper T cells
What does it mean by retro virus
Going backwards then forwards
Transcription
Copying 2 dna strands into rna
Life cycle of HIV: initially contains
2 rna strands
-ssrna (single strand)
Life cycle of HIV: begins penetrating cell with ___ and ____
Spike and enzyme reverse transcriptase
Reverse transcriptase cannot be made in
Humans
Life cycle of HIV: spike/enzyme attaches to
Helper T cell
-CD4 cells
Life cycle of HIV: enters cell via and does what
Endocytosis (receptor mediated)
Mergers with CD4 cell
Life cycle of HIV: how does the cell enter via endocytosis
Using spike gp 41+120
Life cycle of HIV: begins to ___ and releases
Uncoat, RNA + reverse transcriptase
Life cycle of HIV: multiplies within cytoplasm to
Synthesize own model
Life cycle of HIV: reverse transcription occurs via
Reverse transcriptase
What is reverse transcription
RNA to DNA
Steps of the reverse transcriptase
- Copy rna into a single dna
- RNA degrades, left with 1dna
- Recoup dna to create a double strand
Provirus stage of HIV
Has established and integrated itself into dna
-can synthesize new virgins
-can become latent virus
-converts cell into cancerous cell
Latent means the virus is
Waiting four host helalth to diminish then act
HIV 1
USA and Europe
HIV 2
West Africa
CDC
Center for disease control
How many stages of HIV
Three
HIV stage 1
TH = 500 cells/mm2
-50 percent or less
Normal TH count is
1000 to 1500 cells/mm2
Stage 2 HIV
Amount of CD4 is declining
-TH = 499 to 200 cells/mm2
-immunodeficiency symptom
Immunodeficiency symptom
Swollen lymph nodes
-suspeptible to (shingles, fungal/UTI, diarrhea, fever)
Stage 3 HIV
TH = 200 cell/mm2
-cancer stage
-other infections
Cancer in stage 3
Kaposis sarcomma
-cancer of skin and blood vessels
Other infections in stage 3
TB, pneumonia, eye infections
Simian immunodeficiency
HIV 2 came from
-monkeys to us
HIV treatment
Several different drugs help to destroy enzyme RT
-cocktail mixture
Two examples of HIV treatment drugs
Zidovudine (AZT) and laminuridine (3TC)
Why is there no vaccine development for HIV
Process of copying the dna has many mutations
-its different for each person
What type of vaccine is being studied for HIV
MRNA vaccine
-to reduce speed of HIV
How does HIV spread
-blood
-sexual transition (semen)
-breast milk
Lyric viral infection
Good infection
-kills cell but gets rid of virus as it dies
Example- cold, rhino virus
Persistent viral infection
Slow, mythological, deadly over long period fo time
Example- brain degeneration in measles
Latent viral infections
Hides in cells then emerges
Example- herpies 1: causes cold sores, shingles, mono
Cancer viral infections
Normal cells turns into cancer cell
Example- burkitts lymphoma (b lymphocytes around jaw region)
Three main avenues for pathogens to enter
-mucous membrane of major organ systems
-skin
-parenteral
Mucous membrane of major organ systems
-respiratory tract
-GI tract
-GU tract
-eye/conjectiva
Skin
Innate but still vulnerable
-fungal infections
Parenteral
Broken skin that gives direct entery into blood
-bite, catheter, needle
Example- malaria
Adherence
Ability to attach to cells and invade tissues
-forms link with host
Host contains
Receptors (sugar, present on cell membrane)
Pathogen contains
Adhesions (enable sugar to match up)
Adhesions are made up of
Glycoproteins or lipoproteins
Adhesions can be found in what four forms
-on capsule
-fimbrae
-flagella
-cell wall
An example of capsule adhesions
S. Mutants
S.mutants and adhesions: attach…
Attach by capsule, and use enzyme glucosyltransferaze to metabolize sugar
S.mutants turns sugar into
Glucose and fructose, then glucose into glucose and fructose into acid
Glucose into glucan
Is the gummy sugar found on teeth that forms plaque
Plaque and acid
Acid soaks into gummy sugar and begins breaking down teeth
Examples of fimbrae
E.coli and n.gonorrhea
N.gonorrhea and fimbrae
Contains protein called opa, that is found on fimbrae
S. Pyogenes and attachment
Contains an M protein, that is found outside cell wall that is resistant to heat/acid and phagocytosis
Invasion technique
Penetrating host defences
-exoenzymes (there are four)
Four exoenzymes that process invasion
-coagulase
-kinase
-hyaluronidase
-collagenase
Coagulase
Turns fibrinogen to fibrin, creating a CLOT
Example- s.aureus
Kinase
Breaks fimbrae clot and leaves body vulnerable to more invasion
-more bacteria released to travel through body
Example- s.pyogenes
Hyaluronidase
Fragment/breaks down tissue
Example- colistridum perfringes (necrotic tissue)
s.Pyogenes (flesh eating disease)
Collagenase
Breaks Down tissue
Example- c.diff (colitis)
Toxaemia
Toxin in hosts blood
Toxoid
Inactivated toxin found in vaccines
Types of toxins
Exotoxin and endotoxin
Exotoxin definition/example
Secretes in human body to cause disease
Example- tetanus (opstitholonos or C shape back spasm)
Exotoxin notes
-can be gram + or -
-byproduct of metabolism
-protein
-circulates in body fluids
-s/s are specific/easily recognizable
-no fever in response
Exotoxin —> antitoxin
Antitoxin is produced by body
-then neutralized
-then toxoid is used to make vaccine
DTaP
Three classes of exotoxins
-classic A+B
-membrane disrupting
-super antigens
Classic A+B
A protein—> ACTIVE (cells react and kill)
B protein—> BINDS (to whole cell then drag A in)
Membrane disrupting exotoxins
-making protein channels (disrupt plasma mem)
-phospholipid bilayer is disrupted (cellular contents flow out)
Super antigens exotoxins
Activate an intense immune response (cytokines)
Symptoms: violent behaviour, nausea, diarrhea, shock
Example- TSS, S.aureus (food poisioning)
Endotoxin
Always present, just needs to release
-lipids
-released more during lyse of bacteria cells
Disseminated intramuscular coagulation
Consequence of endotoxins, activation of blood clotting proteins
-blood clot formation
-gram negative !!!
-decreased blood supply/tissue death
Endotoxic shock
Related to secretion of cytokine by macrophages
-secrete TNF, damages capillaries, lowers bp —> shock
Endotoxins are apart of the
Gram negative cell wall
Endotoxins are produced by
Gram negative
Two large effects of gram negative cells
-fever/pyrogenic
-shock response
Fever
-is a good and natural process
-eventually need to break the process or could potentially end up in coma/brain reaction
Process of fever
Macrophage/monocyte engulf GN bacteria, lipid A is released and triggers monocyte to release INTERLEUKIN-1
What does interleukin-1 do?
Initiates fever by interacting with hypothalamus
Chills stage of fever
Abundance of IL-1 in blood
-shivering
crisis stage
IL-1 decreasing, sweating
Septic shock occurs due to
Change in blood pressure
-lipid A releases Cachein and travels to vital organs changing the permeability of the blood vessels there and causes shock
Which of the two is good for the body? Fever or shock
Fever
-shock is never good
Cachein
Tumour necrosis factor, TNF
Shock symptoms
Nausea, vomiting, kidney failure, turning pale, breathing heavy
Lipid A comes from
Lipopolysacharides
Lipid A causes
Fever, nausea, vomiting, diarrhea, dysentery and eventually septic shock
Can you neutralize endotoxins by antibiotics
No
