Cell organelles
nucleus = contains DNA, brain of cell
lysosom = corrode of particles (proteins) in cell
mitochondria = ATP building, breathing system, metabolism
ER = translation (composition & depletion) transport of proteins
golgi-apparat = modification, packaging in vesicles & transport of proteins
zentriol = arrangement, transport & sustitution of chromosomes
tightly packed tissue
(types of tissue)
cell mechanically coupled with its surrounding neighboring cells
= connecting proteins in membrane
= guaranties stability against shear und tensile forces
zB: epithelial tissue, striated muscle, adipose tissue
tissue of low cell packing density
mechanical cohesion of disorderly distributed cells = provided by extracellucar fibrous matrix
zB: connective tissue, cartilage tissue
Binding types
covalent bonding
Ional bonding
Polar bond
van der waals
Secondary structure
spatial arrangement of close neighboring amino acids = double helix
tertiary structure
3D structure of chain consists of several secondary strucutures = proteins
Enzymes
proteins that control the probability of molecular reactions
zB: conformational change of biomolecules
Lipids
fat like substances
insoluble in water
for building cellular structures
consists of 2 distincltly different parts
Antigenes
molecules of foreign body structures to wich antibodies can bind
are usually proteins, lipids, carbohydrates ot other complexes
any substance that specifically binds with an antibody
Antibody
protein that can bind specifically to a certain antigen according to lock and key principle.
main task = fight foreign bodies that harm the organism
Residues (distinguished from aa)
1) Electrical inactive redisues = hydrophobic
2) polar residues = hydrophilic
3) charged ionic residues = electrostatic alternation
Conformational / charge complemantarity (KLK)
KLK = all variants of biological information processing
consists of 2 complementaries:
1) Conformation: geometric fit = lock and key principle
2) charge: electrically charged positions = electrostatic force couplimg
RNA
used for protein synthesis
as mRNA it is transported to a ribosome where it serves a blueprint for formation of a protein
as tRNA it docks into mRNA and form individual aa which together form a protein (3 bases code for 1 aa)
DNA
different sugar as RNA
consists of bases: Adenin, Cytosin, Guanine, Thymine
consists of 2 primaty chains that form compound latter = wound in double helix
KLK complementary between A & T, G & C
DNA replication = duplication
Topoisomerie: end spining of DNA
Helicase: splitting DNA
Primase: attach short RNA segments = primers, used to initiate actual strand synthesis
Okazaki Fragments: short sections of subsequent strand of DNA
DNA Ligase: linking fragements to form entire strand
Principle of protein synthesis
(DNA -> Protein)
1) DNA segment contrained in gene is exposed
"2) matrix strand relevant for reading in unfolded by local inhibition of electronic base binding
3) analogy to DNA duplication, nuceleotides are added to unfolded matrix strand via KLK
4) nucleotides are chemically covalently linked, resulting in mRNA
5) after uncoupling of mRNA, the DNA closes = mRNA moves from nucleus to cytoplasm
DNA Translation
1) mRNA binds to ribosome
2) tRNA attaches mRNA to each triplet by electrostatic attraction. Important = identication region of tRNA matches base triples on mRNA
3) Depending on base tripe, specific aa is released by tRNA
4) aa = covalent linkage to the other ones & forms protein
5) tRNA is uncoupling & next one can attach
Genetic code protein coding
nucleotides of an RNA encode 20 AA of corresponding type
3 positions (4^3 = 64) are sufficient for clear coding)
Introduction of a foreign gene?
= carried out using recombinant DNA technology
1) DNA containing the gene to be inserted (=fragment G) is divided into fragments by a cutting enzyme = fragments F,G,H, etc
2) Plasmids (DNA carrier molecules) are separated using the same cutting technique = Fragment P
3) the two solutions are mixed together = resulting in recombination of fragments. Aim is to create a combination, in the form of a ring between the gene to be inserted and the plasmid = Fragment G+P
4) G+PP ring is introduced into cell via cell membrane
5) Cell is stimulated to divide
6) through selective procedures only those cells are cultivated that contain G+P ring. The protein that these cells produce is further used
Specific geneti engineering techniques
Cloning: the targeted introduction of a foreign gene into a cell (recombinant DNA technoligy)
Cell fuision = combination of genetic material of two cells in a hybrid cell = fusion of cal A & B - electrical variation
Process of cell fusion
1) watery medium contains both A & B cells. Prerequesites: electrical conductivity is lower that that of intracellular fluid
2) 2 electrodes are now used to apply a high frequency alternating electrical field at frequency of intracellular flux
frequency must be high enough to enable high resistance cell membranes to be bridged by displacement currents ( >100Hz)
leads to polarisation & attracting force between cells
results in cell chains which are genetically favorable & form current path of minimal impedance
3) membrane contact points form a bottleneck of current conduction & molecular order of cells (lipid heads, protein position, etc) is disturbed by effect force.
DC pulse is impressed which leads to a complete destruction of local order = causes a channel between the cells in contact.
4) membrane edges now fuse & fusion takes place
5) Hybrid cells A & B are formed, which however have total volume of both cells & sum of genetic material.
Fusion achiedved by cell division (stability of resulting cells not giaranteed)
6) repetition of steps = multiple fusion with increasing probability
Dispersion
relationship of permittivity to frequency wave
alpha D: LF (0-10kHz)
beta D: HF (0,1-10MHz)
gamma D: microwave (0,1-30GHz)
Complex Permittivity
measure of field weakening effects of dieelectric polarisation
measure of ability to influence electrical fields
Permittivity
property of materual that describes ability to permit the transmission of electrical field
Cellmembrane
Phospholipid double layer
separation of cells
maintaining internal milieu
insertion & attachment of proteins
transport of ions through special channes
Mass-Spectroscopy
Method for measurung the mass-to-charge-ratio of particles
for known charge q = mass m can be determined
molucules ionised by laserbeam
ionised molecules evaluated in analysis chamber on basis of their flow time
Overtemperature in biolog. Material
1) Abrupt heat supply (zB to human body)
2) Start of thermoregulations in bogy (sweating, increased breathing)
3) Tissue heat regulations depend on:
specific heat capacity
blood flow
4) Tissues with high heat cap = absorb more heat energy
5) Tissues with good blood flow = release more heat energy
Dispersionhub (= amplitude / shift / index)
refers to change in refractive index of material with respect to wavelength / frequency
can cause different colors / frequencies of light to be refracted by different amounts
Dispersionfrequency
F at which dispersive effect become visible zB: change in refractive index with wavelength
related to charact. timescales of molecular interaction & resonances with medium
Neuronal effect of external elect. Field
1) Applied surface charge Eext generates own elect. field within cell Ei
left:
Ei distrubs elect. field of restimg membrane ER
Membrane voltage u decreases & becomes more netative than -70mV = hyperpolarisation
right:
induces elect. field Ei opposes ER
membrane voltage increases = depolarisation
2) If depolarisation reaches specific threshold = AP can be triggered
Numerical Aperture
ability to gather light & resolve fine sample details at fixes object distance
the higher the NA the more details u get
NA = sin()*a
Gene expression
biosynthesis of proteins based on specific genetic information
Transcription
RNA processing
mRNA transport
Translation
Protein: targeting, function & degrading
= proteins that control probability of molecular reaction
= biokatalysators that help to speed up metabolism or chemical reactions
= build substances and break others down
= bind to substrate and when: geometrically compatible = lock & key principle
Principle of magnetic lenses
constist of coil with magnetic core ring
generates inhomogenous magnetic field
entering electron hits magnetic filed = deflected by Lorentz Force
Result: helical path that leads to focal point
pH-value
to specifiy acidity or alkaline/basicity of aqueous solutions
measure for concentration of water-ions
pH = - log[H]
Coloring to increase contrast!
most effective procedure = based on mechansim of electro adsorption
Attachement of particles to substrate via electrical attraction forces
supported by diffusion forces resulting from concentration differences
high pH value = all structures are marked
Action Potential
1) Resting Membrane P:
rmp in cell = - 70mV = neurons maintain negative charge inside cell realtive to outside (electrical charge when membrane is at rest)
2) Depolarisation:
AP begins with stimulus
when threshold is reached
triggers the opening of sodium channels = Na rush into cell = depolarisation
3) Rising phase & Peak Potential:
inflow of Na = increase of membrane potential = positive
AP reaches peak when inside of cell positively charged compared to outside
4) Repolarisation:
Following peak potential
voltage gated potassium channels open = outflow of K = restoring negative charge = repolarisation
5) Hyperpolarisation:
in some cells = K outflow can make potential even more negative then resting Potential
6) Resting phase:
cell has stable negative membrane potential = no active transmission of signals
Refractory Phase
follows action potential = period when cell is less responsive to additional stimuli
Absolte RP:
Frequency dependant membrane conductivity
Membrane conductivity changes with frequency of electrical signal
< beta dispersion: Energieumsatz im extrazellulären Raum = indirektes Erwärmen des Zellinneren = keine Verschiebungsströme
> beta dispersion: Verschiebungsströme = direktes Erwärmen des Zellinneren
SL*d / gamma = 30mV
Ion channes in neurons
1) voltage gated
work in respone to change in mem. potential / voltage
potassium / sodium channel
2) ligand gated
work in response to binding specific neurotransmitter
nicotine acetylcholine
3) mechano sensitive:
sensitive to mechanical stimuli: pressure, tension
piezo channels
Ionising Radiation
Ionisation energy must be high enough to remove electron from water molcule = ionising the molecule
for water = 12,56 eV
Non ionising radiation = when energy is below that threshold
zB: radio- & microwaves, infrared radation, visible light
Non ionising radiation effects
Thermal effect:
decreases in intensity when passing through matter (matter absorbs energy)
Photochemical effect:
Z1 converted to Z2
pro Vit D2 (Z1) converted into Vit D2 (Z2)
Genetic engineering
Cloning:
trageted introduction of foreign gene into cell = recombinant DNA technology
Cell fusion:
combination of genetic material of 2 cells in one hybrid cell
Electrophoresis
laboratoy technique to separate mixture of substances / particles in electrical field
refers to electromotive force EMF used to move analytes through electrolyte chamber
Basend on differences: size & electric charge of molecule
Carrier mat: agarose / polyacryamide gel or cellulose acetate film
current: depens on carrier mat & what ions should be analyzed
Agarose gel analysis for separation of NA Ions = 1kV needed
Tetrodotoxin TTX
strongly hydrophilic
selectively blocks voltage gated sodium channels
= transmission of nerve impulses & APs arent blocked = no change in membrane potential
weil diffusionskanäle immer noch offen = ausgleich & AP kann zwar ankommen aber kanäle öffnen nicht
Gleichgewichtspotential
refers to electrical potential across cell membrane when specific type of ion is in equilibrium between concentration & electrochemical gradient
Nernst equation!
TEM
for: DNA structure, membrane structure
Resolution below 1 nm = e beam instead of light
sample thinner 1 micro meter
requires high voltage
only conductive samples
0,3 nm
Preparation: fixation, dehydration, resin embedding
SEM
for: shape of RBC, organelles - surface structure
image formation through scanning
maps surface topography
resolution below 1 nm
3nm
REM
surface topography
light microscope
for: cells, bacterua, mitochondria
passing visible light transmitted through / reflected from same through 1 or more lenses
200nm
x ray microscopy
no sample preparation
resolution micro meter scale
low interaction with sample
x ray transmitted through material = atom absorbs xray radiation = resulting image from: reflection, absorption, transmission
Methods: grid principle, projection method, high resolution xray microscopy
x ray structure analysis
image only produced after mathematical processing = allows measuremetn of biolog. molecules
= röntgen source consists of gluh cathode = e are accelerated onto copper target & shot out of innermost K shell
= then replaced by L electrons that follow
= creates K radiation quantum = represents röntgen radiation
Fluorescence microscopy
specific substances absorb UV light and emit normal light
mercury or xenon lamp to produce UV light
useful for measuring physiological & biochemical events in living cells
2D electrophoresis
1.Dimension: isoelectric focusing = separation occurs by charge IP
2.Dimension: separation by mass
SDS electrophoresis
proteins labelled with negatively charged SDS (sodium dodecyl sulphate)
to strongly
that amount of total charge is proportional to number of aminoacid position
Electrofocusing
uses stron scattering of isoelectric point
pH gradient is build in carrier by opposing acidic anode & alkaline cathode
applied proteins mive until they have reached location: pH = PI
proteins move faster when pH-values decrease
Isoelectric Point
specific pH value where entire protein molecule habe electrical net charge of 0
at IP: proteins behave electrically neutral
Displacement polarisation
in gamma dispertion in HF range
field intensity E acting on matter causes shit of center if gravity of electrons with respect to cog of protons
Orientation polarisation
in gamma dispersion in LF range
orientation of such molucule at field E which also shows polar moment for E = 0
Lorentz equation
F = e(B*V)
in magnetic field
moving electron is subject to lorentz force
perpendicular to direction of movement of charge
Metal / electrolyte charge boundaries
in alpha dispersion
when negative voltage is applied = ions & watermolecules attach themselve
forms layer with insulating effect
Opiates & G-Strophantin
1) Oubain = drug = inhibits NA/K pump
2) inhibition interrupts normal balance & increases Na concentration inside cell
3) Higher intracellular sodium level = decreased driving force for Na/Ca transporter = weakened pump
4) less Ca transportet out of cell
5) increased Ca level in heart muscle = increased concentration performance
Mylinised fibres
nerve fibers insulated in glial cells
compensatory current can only close at short non insulated section = noce of ranvier
Result: mm long reactions are bridged abruptly = faster signal transmission
Muscle contraction
Corntrol:
P generated by snynapse propagate along muscle membrane at 1 m/s
static maintainance of state of concentration can be seen
Regulation:
Activation of different parts of fibers from muscle
Activation of different numbers of synapses
Variation of AP impulse train frequency / AP impulse train duration
excitatory synapse
inhibitory synapse
from ESPS in postsynaptic cell = causes depolarisation
leads to postsynaptical inhibitory potential ISPS = inhibits depolarisation
Black widdow poison
toxin releases AP = cramps & pain
when transmitter supply exhausted = no more real stimulus information transmitted = paralysis
paralysis of respiratory system = death
Superposition law
means that waves can overlapt without influencing each other
Fire rule: UAH = UA;AH + delta UAH > USAH
= large number of small counteraction of ISPS must interact tp reach threshold
ventricular vibration
ventr. frequency is greatly increase = mechanical pumping of heart comes to stop !
normal state:
action impulses from sinus node = only after global repolarisation = sinus n generates next impulse
triggering:
disturbance of spacial or temporal depolarisation pattern
impulse is transferred to the initial area of the pathway analogue to an oscillating circuit feedback & upright circular movement is created = strongly increased frequency = loss of coordinated pumping power
Remedy = defibrillation = injecting high current impulse in thoray = global excitation of heart = global reolarised state = sinus node can determine ecxitation again
Sinusoidal current waveform
Low frequencies = high Threshold value (SS) −→ Accommodation
Minimum SS at 30-100 Hz −→ technically used range
Increasing SS with increasing frequency
Displacement currents from 30 kHz −→ no neural effects
Current flow through body
flow through organism = sequence of tissue layer must be flowed through = dirfferetn conductivity !
layers in series = constand change of current density = change in electrical filed & power density
long exposure to current = destructive mechanism starts = degrading cell membranes
Threshold value for square pulse
high threshold = short pulse
Reason:
current flowing through the membrane is composed of: density line current SL
density displacement current SV
AI triggered when 30mV reached
at certain switch on time = no further reduction of threshold value
ss drops to 0
minimum ss value = rheobase
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