Lernkartei Biophysics (Seite 5 von 11)

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Lernende	15
Sprache	English
Kategorie	Medizin
Stufe	Universität
Erstellt / Aktualisiert	29.01.2019 / 12.02.2022
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214) Chemical shift in the NMR spectra is related to:

a) Chemical reaction due to interaction with the magnetic field

b) Modifications of local magnetic fields around protons by their chemical environment

c) Displacement of atoms within a chemical structure of a particle

d) Shift in the equilibrium of a chemical reaction

e) Change in the atomic spin due to a chemical reaction

215) Indicate the true sentence

a) Relaxation time T2 is longer than T1

c) Relaxation time T2 is longer than T1 for bones but T1 is longer for blood and muscles

b) Relaxation time T1 is longer than T2

d) Relaxation time T1 is longer than T2 for bones but T2 is longer for blood and muscles

e) Relaxation between T1 and T2 depends on the induction of magnetic field and may reserve a low or high B value

216) To determine images dependent mostly on proton density, the operator needs to set recordings at (abbreviations TR = repetition time, TE = time to echo)

a) Short TR and short TE

c) Short TR and long TE

d) Long TR and long TE

b) Long TR and short TE

e) Stationary recordings (without any magnetic field pulses) should be applied

217) In the harmonic movement a particle is oscillating around the equilibrium point and y denotes the distance of particle from the equilibrium point. The harmonic force (F) inducing the harmonic movement is described as follows (k is the spring constant):

a) F=sin(y)

b) F=-ky – Hooke’s law

c) F=cos(ky)

d) F=k*IN

e) F=k/y

218) Choose the correct statement for the neuromuscular junction:

a) Presence of neurotransmitter within synaptic cleft lasts longer than the postsynaptic potential

b) Presence of neurotransmitter within the synaptic cleft lasts longer than the action potential in the sarcolemma

c) Presence of neurotransmitter with the synaptic cleft lasts shorter than the postsynaptic potential

d) Presence of neurotransmitter within the synaptic cleft lasts shorter than the post- synaptic potential but is longer than the action potential

e) Time duration of neurotransmitter presence within the synaptic cleft is unknown

219) Indicate the phenomena that do not contribute to electrodiffusion:

a) Migration in the magnetic field

b) Diffusion

c) Movement of anions through the pore of GABA receptors at a chemical synapse

d) Movement of ions down the chemical gradient

e) Movement of ions driven by non-homogenous electrical field

221) Ultrasound beam is propagated through a soft tissue and enters one indicated below. Indicate when the reflection will be minimal:

a) air

b) cartilage

c) lungs

d) soft tissue

e) bones

222) At a defined frequency (1000 Hz) how much the sound intensity needs to be increased to increase the sensation of sound loudness by 200%.

a) Sound Intensity must be increased by 200 %.

b) Sound Intensity must be increased by 300%

c) Sound Intensity must be increased by 1000%

d) Sound Intensity must be increased by 5000%

e) Sound Intensity must be increased by 10000%

223) Two sounds were found to be characterized by the same basal frequency but different weights of higher harmonics. When listening these sounds we will report that

a) Sounds are characterized by the same timber

b) Sounds are Characterized by the same pitch

c) The perception of these sounds is exactly the same

d) Cannot be specified because the sound perception depends on the emission angle

e) Cannot be specified because sound perception depends on individual features

225) The major role of the outer hair cells in the Corti apparatus is

a) Transmit signals to spiral ganglion cells

b) To amplify the oscillations at the basilar membrane

c) To transmit electrical signal to the inner hair cells

d) To create negative feedback protecting the Corti apparatus form damage in case of excessive stimuli

e) To cause the membrane depolarization whereas the inner cells induce hyperpolarization

226) Electric charge q is moving with velocity v in the magnetic field characterized by induction B. Assuming that velocity vector is perpendicular to the induction vector B, the force acting on the charge will have the orientation:

a) Parallel to B

b) Parallel to v

c) Antiparallel to B

d) Antiparallel to v

e) Perpendicular both to v and B

227) In which conditions a proton in the presence of external magnetic field (B0) is in the state characterized by the highest energy (µ is the magnetic moment of the proton)

a)When B0 is perpendicular to µ

b) When B0 is parallel to µ

d) When B0 is antiparallel to µ and absorbs energy quantum

c) When B0 is antiparallel to µ

e) When there is a dipole-like interaction with another proton

228) Indicate the correct definition of the magnetic field induction (B) unit (abbreviation: N-newton, A- amper, m – metre)

a) 1 Tesla = N/(Am)

b) 1 Tesla = N/m

c) 1 Tesla = A/N

d) 1 Tesla = Nm

e) 1 Tesla = AN

229) Order the tissues with respect to proton densities (from highest to lowest).

a) Muscles, Brain WM, Brain GM, CSF, Bones

b) Bones, Muscles, CSF, Brain WM, Brain GM

c) Muscles, CSF, Brain GM, Brain WM, Bones

d) Brain WM, Brain GM, Muscles, CSF, Bones

e) CSF, Muscles, Brain WM, Brain GM, Bones

230) Magnetization M is

a) Vectorial sum of magnetic moments

b) Is an intrinsic feature of ferromagnetic materials which distinguishes them from other materials

c) Is the current in the coils of NMR apparatus, responsible to inducing magnetic field

d) Is a synonym of magnetic moment

e) Is the value of magnetic moment in the case of homogenous magnetic field

231) Relaxation time T1 describes the process (symbols: Ms is the component of magnetization M parallel to external magnetic field B0)

a) In which the Mx is being dissipated

b) In which synchronicity of magnetic moments precession is increased

c) In which the value of Mx is being rebuilt after a pulse of electromagnetic wave with magnetic field perpendicular to B0

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

e) In which atoms start synchronous oscillations

233) Electric field is applied to invert the MZ and then the time course of magnetic changes are measured

b) rf 90° pulse is applied to rotate MZ to the transverse plane (perpendicular to Bz) and the kinetics of rebuilding of MZ is measured

c) BO is reduced and increased again to assess the kinetics of changes in MZ va…

d) The frequency of Larmor’s precession is established

e) The increase in the crystal temperature is measured after rf 90°

234) What happens to the membrane capacitance of a cell if both its surface area and thickness increase two fold (two times)?

a. Membrane capacitance does not change

b. Membrane capacitance increases 2 fold

c. Membrane capacitance decreases 2 fold

d. Membrane capacitance decreases 4 fold

e. Membrane capacitance increases 4 fold

235) Indicate the effect of the inward (from outside towards inside the cell) current of anions flowing through the cytoplasmic membrane

a. Enlargement of the membrane thickness

b. Change in the value of the electric field intensity but no change in the membrane voltage

c. Change in the value of the membrane voltage but no change in the intensity of electric field

d. Change in the membrane potential towards negative values

e. Increase in the membrane capacitance

236) The considered system can be found in the two states: state S1 characterized by the energy U1 and state S2 characterized by the energy U2. If U1 > U2 then

a) State S1 is more likely to occur than the state S2

b) State S2 is more likely to occur than the state S1

c) The S1 and S2 states may occur with equal probability

d) To characterize the occurrence probabilities of these states we would need to know the values of their spin

e)The entropy of S1 is larger than entropy of S2

237) If the intracellular concentration of a cation is larger than the extracellular one, the Nernst equilibrium potential for this ion is:

a) Negative

b) Negative only for bivalent cations

c) Positive

d) Positive only for bivalent cations

e) Depends on the intensity of the active transport

239) Indicate the effect of hydrogen bonding water

a) Increase in boiling temperature

b) Decrease in boiling temperature

c) Increase in volume

d) Increase in local pressure

e) Decrease in melting temperature

241) When the function of the f channels in the SA node is increased:

- Heartbeat frequency is decreased

- Heartbeat frequency is increased

- Heartbeat frequency is not changed: but the duration of the action potential is prolonged

- Heartbeat frequency is not changed: but the amplitude of action potential is prolonged

- The Nernst potential for potassium ions will change

242) The first principle of thermodynamics for ideal gas states that the change of internal energy of a closed system is equal to

- Product of entropy and temperature of the system

- Heat supplied

- Sum of heat and free energy

- Sum of energy of interaction between particles

- Sum of heat and work excerted on or by the system

243) Indicate where are localized hirachial pacemakers in the heart

- Purkijne fibers, SA node, ventricular muscles

- SA node, atrial muscles, Purkijne fibers

- SA node, AV node, Purkijne fibers

- SA node, atrial muscles, ventricular muscles

- Atrial muscles, SA node, ventricular muscles from the heart septum (think it said so)

244) The sample contains 2000 atoms of radioactive isotope whose half-life is 50 years. Radioactive decays will reduce the initial number of radioactive atoms to 125 after:

- 100 years

- 187,5 years

- 200 years

- 250 years

- 375 years

245) Radiation-induced ionization of gas occurs in

- Scintillation – counter : scintillator which generates photons of light in response to incident radiation

- Photographic film: for film

- Geiger – counter

- Semiconductour counter

- Galvanometer : A galvanometer is a type of sensitive ammeter: an instrument for detecting electric current

246) Van der Waals attractive interactions are due to:

- Covalent reactions

- Dipole interactions

- Hydrogen bonds

- Short distance strong (rigid) repulsion

- Energy supplied by external force when decreasing the system entrophy

247) After a light absorption by a photoreceptor the membrane potential:

- Depolarized due to opening of voltage-gated sodium channels

- Hyperpolarized due to opening of voltage gated calcium channels

- Depolarized due to opening of cation selective channels activated by cAMP

- Hyperpolarized due to closure of cation selective channels activated by cAMP

- Hyperpolarized due to closure of cation selective channels activated by cGMP

248) The force of electrostatic interaction between two electrical charges is:

- Prop. to the distance between electrical charges

- Inversely prop. to the distance between electrical charges -

- Prop. to the product of the two electrical charges

- Prop. to the square of the distance between electrical charges

- Inversely prop. to the sixth power of the distance

249) The energy of interaction between two dipoles is:

- Prop. to the square of the distance between electrical charges

- Prop. to the distance between electrical charges

- Inversely prop. to the sixth power of the distance

- Inversely prop. to the distance between electrical charges

- Inversely prop. to the square of the distance between electrical charges

253) The energy of interaction between two dipoles is:

A. Proportional to the square of the distance between electrical charges

B. Proportional to the distance between electrical charges

C. Inversely proportional to the sixth power of the distance

D. Inversely proportional to the distance between electrical charges

E. Inversely proportional to the square of the distance between electrical charges

254) Van der Waals attractive interactions are due to

A. covalent reactions

B. dipole interactions

C. hydrogen bonds

D. short distance strong (rigid) repulsion

E. energy supplied by external force when decreasing the system entropy

255) Radiation-induced ionization of gas occurs in:

A. scintillation counter

B. photographic film

C. galvanometer

D. Geiger counter

E. semiconductor counter

256) The sample contains 2000 atoms of radioactive isotope whose half-life is 50 years. Radioactive decays will reduce the initial number of radioactive atoms to 125 after:

A. 100 years

B. 187,5 years

C. 200 years

D. 250 years

E. 375 years

257) During MRI scan a patient is placed in the constant magnetic field of a scanner and the protons in patient’s body absorb pulses of electromagnetic radiation whose frequency is typical for:

A. X-ray

B. infrared

C. radio waves

D. ultraviolet

E. microwaves

260) The NMR phenomenon is related to:

A. emission of ultrafiolet radiation

B. emission of gamma rays from atomic nuclei

C. absorption of quanta of electromagnetic radiation correlated with change in the spin moment orientation

D. absorption of infrared radiation

E. absorption of energy carried by ultrasounds

262) The intensity of the electrical field (E = U/d, U – voltage, d – distance) within the biological membrane is close to:

A. 10 ^-5 V/m

B. 1 V/m

C. 100 mV/m

D. 10^7 V/m

E. 10^3 V/m

263) The phenomenon of viscosity is related to:

A. elastic deformations of blood vessels

B. friction (and energy transfer) between liquid layers showing a laminar flow

C. difficulties in the blood flow because of vessel’s occlusion

D. adhesion of fluids to the vessel’s walls due to molecular interactions

E. sticking of fluid due to excessive bonding (polimerization)

265) After action potential generation in the axon:

A. a second action potential can be generated immediately

B. a second action potential can be generated after a refractory period

C. a second action potential can be generated after approx. 10 s

D. a second action potential can be generated almost immediately but shows a smaller amplitude

E. a second action potential can be generated after approx. 1 s

Biophysics

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