Cartes mémoires Biophysics 2 (Seite 1 von 2)

Cartes-fiches	41
Langue	English
Catégorie	Médecine
Niveau	Université
Crée / Actualisé	09.02.2020 / 01.03.2020
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Human ear shows the highest sensitivity for sounds characterized by:

a) Homogeneous timbre

b) Frequency between 10 – 20000 HZ

c) Frequency of approximately 1000 Hz

d) Frequency of approximately 3000 Hz

e) Frequency of approximately 10000 Hz

Blood velocity in the vessels can be estimated when applying:

a) fMRI

b) Infrared waves

c) Measurements of pulse frequency at different sites

d) Calculations of the acoustic resistances

e) Doppler effect

Indicate proper statement regarding X and gamma rays

a) gamma rays are corpuscular and X rays are electromagnetic

b) gamma rays are electromagnetic and X rays are corpuscular

c) gamma and X-rays are both corpuscular but consist of different elementary particles

d) gamma and X-rays have both electromagnetic nature

e) gamma and X rays have the same frequency spectrum

The feature that a lens focuses the light not at a focal point but at a blurred spot is referred to as:

a) chromatic aberration

b) spherical aberration

c) astigmatism

d) diffraction

e) refraction

Typically, the wavelength of absorbed photon is:

a) Longer than that of the emitted one

b) Equal to that of the emitted one

c) Shorter than that of the emitted one

d) Is shortened due to radiationless transitions

e) Equal to the Larmor’s precession frequency

The energy of interaction between the magnetic moment and the external magnetic field is minimal when:

a) Magnetic moment and magnetic field are antiparallel

b) Magnetic moment and magnetic field are parallel

c) Magnetic moment and magnetic field are perpendicular

d) The angle between magnetic moment and magnetic field is 135 degrees

e) The energy of interaction does not depend on the angles between these quantities

In the MRI scanning, the gradients of magnetic field are used to:

a) Enhance the intensity of the signal

b) Facilitate the phenomenon of magnetic resonance

c) To get rid of radiationless transitions in the nuclei

d) To enable examination of a defined tiny part (slice) of the patient’s body

e) To facilitate the T2 relaxation time

Indicate in which units is measured the ECG signal:

a) Volts/time

b) Ampers/time

c) Volts

d) Ampers

e) Tesla

Indicate where in the heart tissue, the propagation of excitability occurs with the lowest velocity

a) sinoatrial node

b) atrial muscles

c) atrioventricular node

d) ventrical muscles

e) Purkynje fibers

Sensory neurons are typically:

a) Characterized by extensive axonal arborization

b) multipolar

c) unipolar

d) forming synapses on cell bodies

e) forming synapses on glial cells

In the electrolyte, local intensity of electric field

a) Is proportional to the local potential difference per unit distance

b) Is proportional to the density of ions

c) Is inversely proportional to the temperature

d) Is proportional to the pressure

e) Is proportional to the resistance of the electrolyte

Assuming that the membrane voltage is 100 mV and the membrane thickness is 10 nm, the intensity of electric field is:

a) 100 mS (S – simens)

b) 1000 mA (A – amper)

c) 10^9 V/m

d) 10 mS

e) 1000 µS

The intracellular concentration of chloride ions is increased while the extracellular one remains unchanged. Indicate how this change will affect the value of the equilibrium potential for chloride ions (V_Cl).

a) VCl decreases (changes towards values) negative

b) VCl increases (changes towards positive values)

c) Impossible to determine because the concentration values are unknown

d) VCl will show oscillatory changes

In an electrophysiological experiment the number of moles of electrical charges per membrane surface unit and per unit time is determined. The name of the physical quantity measured in this experiment is:

a) current

b) current density

c) local potential difference

d) surface potential

e) chemical potential

The phenomenon of diffusion is quantitatively described by:

a) Fick’s law

b) Bernoulli law

c) Ohm’s law for electrolytes

d) Van der Vaals interactions between ions flowing in the electrical field

e) Conservation principle for electric charges

Indicate a typical width of the synaptic cleft (distance between pre- and postsynaptic membrane) of a chemical synapse:

a) 1 µm

b) 30 nm

c) 0.5 µm

d) 5 µm

e) 1 nm

The speed of the acoustic wave in an elastic medium is: (E - volume elasticity module, r- medium density)

a) Proportional to the square root of E

b) Proportional to E

c) Proportional to 

d) Inversely proportional to 

e) Proportional to the square root of temperature

The sound velocity is measured in the air, water and in a metallic crystal. The sound velocity is found to be:

a) Highest in the air and smallest in the crystal

b) Highest in the water and smallest in the air

c) Highest in the crystal and smallest in the water

d) Highest in the crystal and smallest in the air

e) Highest in the air and smallest in the water

The sound intensity is defined as:

b) Energy/time

c) Energy/surface

d) Energy/(surface·time)

e) Equivalent to energy

In the photoelectric effect the ionization of atom takes place because:

a) Photon induces emission of electrons from orbitals

b) Photon induces emission of electrons from the nucleus

c) alpha particle induces emission of electrons from orbitals

d) alpha particle induces emission of electrons from nucleus

e) gamma ray is being transformed into the electron and positron

Indicate a correct statement

a) electromagnetic waves with wavelength immediately below the visible range are referred to as infraviolet

b) electromagnetic waves with wavelength immediately above the visible range are referred to as infrared

c) electromagnetic waves with wavelength immediately above the visible range are referred to as ultrared

d) electromagnetic waves with wavelength immediately above the visible range are referred to as ultraviolet

e) X rays can be defined as infrared

Which neurotransmitter is released by the mammalian rod cells in the retina:

a) cyclic GMP

b) cyclic AMP

c) acetylocholine

d) glutamate

e) GABA

Indicate how the energy of interaction between a charge and dipole depend on distance (r) between them:

a) Proportional to r2

b) Proportional to r4

c) Proportional to r8

d) Inversely proportional to r2

e) Inversely proportional to r4

The property of the sodium-potassium pump referred to as “electrogenic” is related to the fact that:

a) The pump is passively transporting ions

b) The functioning of the pump directly determines the value of the resting membrane potential

c) The pump is voltage-dependent

d) The pump in each cycle carries a net electric charge through the membrane

e) The pump has a capacity to ionize the organic polymers

The direct impact of the electrogenic action of the sodium-potassium pump on the value of the resting membrane potential is:

a) Equal to zero as the resting potential is totally set by the passive transport

b) Crucial because electrogenicity of sodium-potassium pumps is the basic mechanism of the resting membrane potential

c) To contribute to approximately 5-10% of the value of the resting membrane potential

d) Not known

e) Is maximum at the equilibrium potential for chloride ions

When a negatively charged ion (anion) crosses the membrane from inside to outside of the membrane, the value of the membrane potential will:

a) Not be affected at all

b) Depolarize

c) Hyperpolarize

d) First hyperpolarize and then depolarize

e) First depolarize and then hyperpolarize

A robust excess of extracellular potassium concentration ([K]_out) is known to lead to the cardiac arrest. Indicate most important cause of this effect:

a) A large increase in [K]out leads to membrane hyperpolarization

b) A large increase in [K]out leads to excessive activation of sodium potassium pumps

c) A large increase in [K]out leads to membrane depolarization which induces sodium channel inactivation and thereby membrane refraction

d) A large increase in [K]out causes depolarization and very frequent generation of action potentials which, in turn, dismantles ion concentration gradients

e) A large increase in [K]out causes structural instability of the ionic channels

Indicate the fastest mechanism of communication between two cells

a) Transmission in the chemical glutaminergic synapse

b) Transmission in the chemical GABAergic synapse

c) Release of modulators affecting the second messengers

d) Transmission in the electrical synapse

e) Covalent bonding with the extracellular matrix proteins

Nicotinic Acetylcholine receptors are:

a) anionoselective

b) cationoselective

c) selective for both anions and cations but to a different extent

d) inwardly rectifying

e) activated by intracellular nucleotides

Indicate the name of the disorder characterized by the following symptoms: muscle fatigability, deficit of acetylcholine receptors at the muscular endplates :

a) myothonia

b) fast channel myasthenic syndrom

c) myasthenia gravis

d) intoxication with strychnine

e) Alzheimer disease

In myothonia congenita the skeletal muscle fibers are:

a) Damaged because of the autoimmune action against the epitopes localized on their surface

b) Excessively excitable

c) Showing severe deficit in the excitability

d) Aberrantly innervated

e) Characterized by reduced number of acetylcholine receptors at the endplates

Indicate the type of channel responsible for a slow depolarization of the diastolic potential in the sino-atrial node

a) Voltage-gated sodium channel

b) Chloride channel

c) Inward rectifier potassium channel

d) Hyperpolarization-activated, cyclic nucleotide gated channel

e) Delayed rectifier potassium channels

The unipolar electrode is placed above the excitable tissue in which the action potential propagates as indicated by the arrow and distribution of charges. What happens with the signal measured with the electrode when the excitation frontline is reaches the point immediately below the electrode ?

a) Signal reaches its positive amplitude (maximum)

b) Signal reaches its negative amplitude (minimum)

c) Signal value becomes equal to zero

d) Signal suddenly increases but not reaching maximum

e) Cannot be established basing on this information

Which electrocardiogram wave can be attributed to the atrial diastole

Q

R

S

T

none

If we measure, for the sake of experiment, the blood pressure to a subject in the standing position and the cuff is placed on the part of the arm kept high above the head, then the measured values of systolic/diastolic pressures will read:

a) Normal (i.e. approximately 120/80 Hg)

b) Markedly lower than normal (both systolic and diastolic)

c) Markedly higher than normal (both systolic and diastolic)

d) Vein pressure will be higher and arterial pressure will be lower

e) Vein pressure will be lower and arterial pressure will be higher

Indicate the orders of magnitude for number of photoreceptors and ganglion cells in the human eye retina

a) 10^9 photoreceptors and 10^6 ganglion cells

b) 10^5 photoreceptors and 10^6 ganglion cells

c) 10^7 photoreceptors and 10^4 ganglion cells

d) 101^1 photoreceptors and 10^5 ganglion cells

When the degree of order in the isolated system increases

a) The entropy increases

b) The free energy of the system decreases

c) The chemical potential increases

d) The chemical potential decreases

e) The entropy decreases

When cells are suspended in a hypotonic solution:

a) They tend to swell due to solvent transport into the cytoplasm

b) They tend to swell due to ion transport into the cytoplasm

c) They tend to shrink due to solvent transport into the cytoplasm

d) They tend to shrink due to ion transport into the cytoplasm

e) Osmotic pressure occurs but the volume of cells does not change

The incoming acoustic stimulus has induced a deformation of the basilar membrane very close to the oval window. We may deduce that the detected voice

a) Is characterized by a low frequency

b) Is characterized by a high intensity level

c) Is characterized by a high frequency

d) Is characterized by a low intensity level

e) Is characterized by a short time duration

Relaxation time T1 describes the process (symbols: M_z is the component of magnetization M parallel to external magnetic field B_o)

a) In which the Mz is being dissipated

b) In which synchronicity of magnetic moments precession is increased

c) In which the value of Mz is being rebuilt after a pulse of electromagnetic wave with magnetic field perpendicular to Bo (so called 90o pulse)

d) In which a deformed atomic lattice is returning to its resting state

e) In which atoms start synchronous oscillations

Biophysics 2

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