Set of flashcards Biophysics 2 (Page 4 of 9)

Flashcards	326
Students	14
Language	Deutsch
Category	Physics
Level	University
Created / Updated	09.02.2017 / 09.02.2020
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Blood is a non-newtonian fluid because

It has relatively big density

It has high temperature

It contains many cells (erythrocytes, etc)

None of the above

Let Re denote the Raynolds number, The flow is lamin...

Adjacent fluid layers do not mix and Re > 3000

Adjacent fluid layers do not mix and Re < 2300

Adjacent fluid layers can mix but Re < 2300

Adjacent fluid layers can mix but Re > 3000

The average pressure difference driving the blood flow ... about

100 Pa

100 hPa

100 mmHg

10 mmHg

Blood flow in aorta is

Laminar with constant velocity

Turbulent with constant velocity

Laminal with periodically changing velocity

Turbulent with periodically changing velocity

The molecular mechanism of diffusion is based on:

random, thermal walk of molecules

force acting on molecules due to the concentration difference

electrical force acting on charged molecules

collisions of heavier and lighter molecules

The osmotic pressure can be described as:

pressure difference across selective membrane preventing the electrodiffusional flow

pressure difference across semipermeable membrane preventing diffusional flow of solute

pressure difference across semipermeable membrane preventing the diffusional flow of solvent

pressure difference across selective membrane preventing the flow of solute

At Nernst equilibrium the electric field causes the migration flow:

of magnitude and direction identical as diffusion flow

of magnitude identical but direction opposite to diffusion flow

of magnitude smaller than diffusion flow and direction opposite to diffusion flow

of magnitude bigger than diffusion flow and direction opposite to diffusion flow

When comparing simple diffusion and facilitated diffusion the right conclusion is:

for any facilitated diffusion the flow is bigger than for simple diffusion

there are no differences between both flows

simple diffusion flow saturates at high enough concentration differences and facilitated diffusion flow not

facilitated diffusion flow saturates at high enough concentration differences and simple diffusion not

Sodium potassium pump is an active transport mechanism because:

ions are transported in direction opposite to concentration gradient

the amount of charge transported into the cell is not equal to that transported outward

transport is driven by energy obtained from ATP hydrolysis

all answers are right

Comparing the membrane permeabilities for different ions in the rest.. one can write:

Pk >> PNa and Pk > Pcl

Pk >> PCl and Pk > PNa

PNa >> Pk and Pk > PCl

Pk < PNa and Pk >> Pcl

Increase of the extracellular concentration of potassium ions will cause following change of the neuron's membrane resting potential:

decrease of membrane potential (more negative values)

increase of membrane potential (more positive values)

no changes will be observed

membrane potential will start to oscillate

Voltage-sensitive ion channel is a:

membrane peripheral protein controlling the passage of ions across membrane

charged polymer molecule passing the ions across membrane

membrane integral protein controlling the passage of ions across membrane

complex of molecules co-operating in controlled passage of ions across membrane

Functional components of ligand-gated channel are:

voltage sensor, ligand binding site, activation gate

voltage sensor, ligand binding site, selectivity filter

ligand binding site, activation gate, selectivity filter

voltage sensor, activation gate, selectivity filter

Threshold depolarization of cell is a:

membrane potential at which action potential is generated in excitable cell

peak value of action potential

membrane potential at which sodium channels start to open

membrane potential at which sodium and potassium currents are balanced

Depolarization phase of action potentials of different cells may be caused by:

sodium or potassium currents

sodium or calcium currents

potassium or calcium currents

all of the above

The mechanism underlying "one way" propagation of action potential is:

desensitization of acetylcholine receptor channels

very fast repolarization of membrane

inactivation of sodium channels

inactivation of potassium channels

Hounsfield units are used

In ultrasonography to convert the density sc... air, 0 for water and 1000 for bones

In ultrasonography to convert the density .... Bones, 0 for water and 100 for air

In computed tomography to convert the atte... grey scale (-1000 is for air, 0 for water and 1000 bones)

In computed tomography to convert the atte... grey scale (-1000 is for bones, 0 for water...

In confocal microscopy an image of a certain pla....

Laser light and pin hole

Beam of electrons and magnetic focusing

Monochromatic light and quantum optics

Visible light and inverted optics

In chemical synapse postsynaptic potentials are generated:

exclusively by ligand-gated cationic channels

by ligand-gated cationic or anionic channels

by voltage-gated cationic channels

by voltage-gated anionic channels

Denoting by v-velocity of action potential propagation, C-membrane capacitance, R- membrane resistance of myelin sheath we may write:

it increases v, R and decreases C

it increases v, C and decreases R

it increases R and decreases C, v

it increases v, R and C

In excitatory and inhibitory synapses the postsynaptic potentials are as follows:

in excitatory depolarization caused by inward sodium current, in inhibitory depolarization caused by outward chloride current

in excitatory depolarization caused by inward sodium current, in inhibitory hyperpolarization caused by outward chloride current

in excitatory depolarization caused by outward sodium current, in inhibitory hyperpolarization caused by outward chloride current.

In excitatory depolarization caused by inward sodium current, in inhibitory hyperpolarization caused by inward chloride current.

In neuro-muscular juction AChR proteins are located mainly:

in the active zones of synaptic button membrane

in the bottom of synaptic folds

in the edges of synaptic folds

they are spread randomly on the surface of end-plate

In striated muscle cells the contraction is triggered by increase of calcium concentration. Calcium ions enter sarcoplasm from:

mitochondria

sarcoplasmic reticulum

extracellular medium

are released by calcium binding proteins

The following sentence about motor unit IS NOT TRUE:

all muscle fibers in single motor unit are innervated by the same neuron

the strength of muscle contraction depends on the number of recruited motor cells.

Fast twich and slow twich fibers can be innervated by the same neuron

Slow twich fibers are....

Spontaneous depolarization:

occurs due to slow sodium influx into the P-cell and leads to the ...of the calcium voltage- dependent channels

occurs due to slow sodium influx into the P-cell and leads to the ...of sodium voltage- dependent channels.

Occurs due to potassium influx into the P-cell and leads to the calcium voltage-dependent channels.

Occurs due to potassium influx into the P-cell and leads to the...sodium voltage-dependent channels.

The difference between uni- and bipolar ECG recording is that:

in unipolar recording only one wire is connected to voltmeter and two wires are used.

In unipolar recording only positive potentials can be recorded and bipolar also negative potentials are recorded

In unipolar recording one of the electrodes is connected to standard (constant) potential and in bipolar recording both electrodes are connected to varying potentials

Answers A and C are correct

Chose proper pair (A and B) to fill in the following sentence: Chemiosmotic coupling is achieved through the structure of A – integral protein of the membrane.

A=complex IV, B= inner mitochondrial

A=complex V, B=inner mitochondrial

A=complex IV, B=outer mitochondrial

A=ATP synthase, B=Outer mitochondrial

Chose proper pairs of certain e-m waves and types of excitations inducing them:

microwaves – rotational, infrared- vibrational, visible – electronic

microwaves-vibrational, infrared – rotational, visible- electronic

microwaves- rotational, infrared – electronic, visible – vibrational

microwaves- electronic, infrared –vibrational, visible-rotational

Proper description of fluorescence and phosphorescence occurring after absorption of photon is given by:

fluorescence lifetime is much shorter than that of phosphorescence, fluorescence is a singlet-singlet process ........

fluorescence lifetime is much shorter than that of phosphorescence, fluorescence is a triplet0singlet process while phosphorescence are between singlet states.

Fluorescence lifetime equal to that of phosphorescence, fluorescence singlet-singlet process while phosphorescence occurs between the singlet states.

Paramagnetic nuclei are

all nuclei with a zero nuclear spin

all nuclei with a non-zero nuclear spin

all nuclei regardless of the nuclear spin

all nuclei with the spin equal to 1

The physiological concentrations of sodium and potassium ions inside and outside a cell are

the same

higher for sodium outside and potassium inside

higher for potassium outside and sodium inside

higher for sodium both inside and outside

The chemiosmotic gradient that couples the oxidation/reduction processes occuring during the oxidative phosphorylation and the production of ATP is provided by

potassium ions

sodium ions

calcium ions

protons

According to the Bekesy’s theory the distance between the amplitude of a travelling wave on basilar membrane and the oval window of the chochlear

increases when the sound frequency is increased

decreases when the sound frequency is increased

may increase or decrease depending on the type of sound

remains unchanged when the sound frequency is increased

Blood is

a newtonian liquid

a non-newtonian liquid

a newtonian liquid when it circulates in arteries and a non-newtonian liquid when it circulates in veins

a newtonian liquid when it circulates in veins and a non-newtonian liquid when it circulates in arteries

The conditions of the nuclear magnetic resonance for protons are met when

the energy of electromagnetic waves is equal to the energy of the parallel orientation of the magnetic moment vectors of protons

the energy of electromagnetic waves is equal to the energy of the anti-parallel orientation of the magnetic moment vectors of protons

the energy of electromagnetic waves is equal to the difference of energy between the parallel and the anti-parallel orientation of the magnetic moment vectors of protons

the energy of electromagnetic waves is equal to the energy of the magnetic moment vectors of protons no matter what their orientation of the magnetic moment vector is

In the process of oxidative phosphorylation

NADH and FADH2 molecules are oxidated and oxygen molecules are reduced

NADH and FADH2 molecule are reduced and oxygen molecules are oxidated

NADH, FADH2 and oxygen molecules are reduced

NADH, FADH2 and oxygen molecules are oxidated

Ion channels, which are present in stereocilla of the inner hair cells are

voltage-gated potassium channels

membrane stretch-activated potassium channels

voltage-gated calcium channel

membrane stretch-activated calcium channels

The energy of interactions between ions and dipoles

does not depend on the distance between molecules

is increased when the distance between molecules increases

is decreased when the distance between molecules increases

may be increased or decreased depending on the type of molecules

According to the first law of thermodynamics the change of the internal energy (deltaU) of any thermodynamic system is

equal to the heat exchanged by the system with the environment (Q)

equal to the work performed by the system (W)

equal to the work W plus the heat Q

equal to the work W minus the heat Q

The energy of a hydrogen bond

is comparable to the energy of van der Waals forces

is comparable to the energy of covalent forces

is lower than the energy of van der Waals forces and higher than energy of covalent forces

is higher than energy of van der Waals forces and lower than the energy of covalent forces

Biophysics 2

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