T5: Infection And Immunity Flashcards
4 types of forensic identification
Dental records
Fingerprints
Blood groups
DNA profiling
Uses of DNA profiling
Identify fluids/individuals
Paternity testing
Track genetic relationships
Paternity’s testing process
DNA band sequence
23 bands (13 loci, 2 chromosomes)
Half align with mother half align with father
DNA profiling gene used
Intron non coding block
Short tandem repeat
2-50bps
Same locus of homologous chromosomes
Different no. Repeats
Different combination of bps
13 loci used
DNA splicing
mRNA —> mature mRNA
Only exons left
DNA profiling process
DNA sample (blood/skin/semen)
STRs extracted using restriction enzymes/amplified with PCR
Fragments separated using gel electrophoresis
Fragments stained
13 loci bands compared
DNA gel electrophoresis process
DNA in gel well (agarose)
Voltage applied
-DNA—> anode
Smaller fragments?no. Repeats faster
Comparison ladder
Compare base pairs
Use X-ray, fluorescence, DNA stain
Polymerase chain reaction
Amplify DNA sequence, make millions of copies from a small sample
25-30 cycles
DNA sample, free DNA nucleotides, DNA primers, DNA polymerase
Desaturated at 95C, H bonds broken, DNA —> ss
Annealing, 55C, 26 primers bind
Elongation, 70*C, DNA synthesis
Virus structure (5)
Some
Receptor proteins
Lipid envelope
Enzymes
All
Protein coat
Nucleic acid
Bacterial cell wall types
Gram +
Cell membrane, thick peptidoglycan
Gram -
Cell membrane, thin peptidoglycan, outer membrane
Compare and contrast viruses and bacteria
V, B
Size: 20-200nm, >1mm
Genetic material: RNA/dsDNA/ssDNA, dsDNA
Membranes: lipid envelope, membrane bound
Need a host cell, can live independently
Name 5 ways of determine time of death
Body temp
Degree of muscle contraction
Extent of decomposition
Forensic entomology
Stages of successio
Body temperature TOD
Normal 36.5-37.5
Respiration stops
Temperature becomes ambient
Factors (size, position, clothing, wind speed, ambient temp, humidity, air vs water)
Muscle contraction TOD
Rigor mortis
ATP need myosin to make actin
Stop respiration
Muscles dont have ATP, fix
Starts 2-4hrs
Finishes 6-8hrs
Starts in face goes down
Muscle fibres breakdown last
Warm, not stiff
Warm, stiff
Cold stiff
Cold not stiff
Extent of decomposition TOD
Bacteria/fungi metabolise tissue
Enzymes digest tissue
Lysosomes rupture
Breakdown cells w enzymes
Anaerobic conditions
Gas forms blisters and bloating
Colour change greenish
Putrefaction, decomp and breakdown, more liquid in corpse
Forensic entomology TOD
Bacterial decomp
Attract insects
Pioneer species lay eggs due to smell/moisture
Maggots feed on tissue
3-4 waves
Increase no. Species
Food source runs out
Succession
Name 4 infection barriers
Skin keratin
Skin flora
Gut flora
Stomach
How is skin keratin an infection barrier
Tough
Waterproof
Prevent pathogen netry
How is skin flora an infection barrier
Bacteria
Adapted to living on skin
Outcompete pathogens
How is gut flora an infection barrier
Intensities
Large bacteria population
Outcompete pathogens
How is the stomach an infection barrier
HCl secreted from parietal cells in stomach lining
pH 2 kills most pathogens
Name 4 non specific immune responses
Inflammatory
Lysozyme action
Phagocytosis
Interferons
Inflammatory response
Damaged mast cells release histamine
Histamine dilates arterioles
Increase capillary permeability
Increase no. WBC going to area
Lysozyme action
Enzymes breaks down bacteria cell walls in tears saliva nd breast milk
Phagocytosis (6)
Macrophages
Neutrophils
Triple lobe nucelus
Pseudopodia engulf bacterium
Phagocytosis vesicle
Lysosome releases digestive enzymes
Interferons
Interfere with viral replication in host cells
Bind to infected CSM receptors
Reduce rate of virus binding
Compare non/specific immune response
Specific
Distinguish non/self
Specific
Diverse
Immunological memory
Activation of T cells process
Macrophage engulfs antigen
MHC + antigen protein —> APC
T helper cell has comp CD4 receptors
Clones T helper cells and makes T memory cells
Activation of B cells process
Cloned T helper cells fuse with APC B cells with comp receptors
Release cytokines and B memory cells
Cytokines and B effector cells differentiate into plasma cells that makes antibodies for the antigens
Primary response
Antibodies from plasma cells bind and label antigens
Macrophages engulf the pathogen
Lysosomes fuse to phagocyte membrane
Release enzymes and digest pathogen
Secondary response process
Infected cell —> APC
cloned T helper cells bind to APC with comp receptors
Cytokines clone memory cells and T killer cells
T killer cells bind to other infected cells with antigens
T killer cells release any es that am,e pores than ions enter the cell through
Water enters the cell via osmosis
Water lysis
Stray pathogens are engulfed by macrophages
Describe the stages of a virus hijacking a host cell
Virus attaches to host cell
Inserts Nucleic acid
Acid replicates
Protein coat synthesised
New virus particles formed
Virus particles released via lysis
HIV infection process
Glycoprotein on membrane binds to T helper CD4
Envelope + T helper membrane fuse
RNA —> cell —> chromosome
Transcriptase and integrase
Tt
Infect T helper cells
Weaker immune system
TB infection process
Granuloma/turburcule, anaerobic tissue of macrophages and bacteria
Bacteria multiply
Destroy lung tissue (decrease SA/ROGE
Suppress T helper/killer/antibodies
Cough blood
Fever/fatigue
Post transcriptal changes
Differential splicing
Pre mRNA removes introns by splicosomes
Exons spliced together —> mRNA
Some/all exons removed/reordered
1 gene —> multiple proteins
Tt
Name 2 types of immunity
Active
Passive
Active immunity
Ag exposure
Lag phase
Protein made
Memory cells, long term protection
Nat: infection
Art: vaccine
Passive immunity
External Ab source
No immune response
Immediat
Short term
No memory cells
Nat: maternal Ab
Art: Ab shot
2 types of antibiotics
Bactreiostatic: prevent multiplication
Bacterioscidal: kill bacteria
Evolutionary antibiotic race
New treatment/antibiotic/vaccine = selection pressure
Evolve resistance
Escape vaccine
Thrive/reproduce/pass in allele
Antibiotic hospital immunity cause
Mor antibiotics
More resistance
More mutation
Antibiotic hospital immunity solutions
Restrict location/frequency of use, reduces selection pressure of antibiotics
Improve hygiene, prevents infection spread
Isolate/screen/report cases, identify risk for/prevent transmission
Methods of HIV transfer
Blood
Sexual fluids
Needle sharing
Mother to foetus
Ways in which antibodies effect antigens
Mark for phagocytosis
Soluble toxins are made insoluble and inactive
Clump microorganisms for phagocytes to engulf
Lysis, break open bacteria cell walls
Benefits of secondary immune response
Shorter lag period
More rapid effector cell reproduction
Greater production of antibodies/T killer cells
