Set of flashcards Biophysics (Page 5 of 5)

Flashcards	177
Language	English
Category	Medical
Level	University
Created / Updated	07.02.2020 / 08.02.2020
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269) mechanism of accommodation is related to the properties of

A. retina

B. cornea

C. corti apparatus

D. lens

E. ganglion cells

270) When the action potential reaches its maximal (peak) value, the membrane potential reaches
approximately:

A. 40 µV

B. -40 µV

C. 40 mV

D. -40 mV

E. 0 V

271) When the action potential reaches its minimal value (hyperpolarization), the neuronal membrane is

A. mosty permeable for anions

B. mosty permeable for calcium ions

C. mosty permeable for chloride ions

D. mosty permeable for sodium ions

E. mosty permeable for potassium cations

323) The main dangerous products of water radiolysis are

a. Free radicals and hydrogen peroxide

b. Free radicals and hydrogen oxide

c. Carbonyl groups and hydrogen peroxide

d. Free electrons and carbonyl groups

324) In photodynamic therapy the energy of light is absorbed by

a. Protein molecule and used for conformational change

b. Single oxygen atom, which becomes thus activated

c. Water molecule and used to become free radicals

d. Photosensitizing molecule and used for the production of single oxygen

325) Amorphus silicon is used in active matrix panels in the following purpose

a. To convert ionization radiation into visible light

b. To use the energy of light release electrons

c. To cover the surface of panel

d. To protect cesium iodide against ionization radiation

326) Comparing the energies carried by different ionization radiations (α,β, γ, X) we obtain

a. γ >β> α>X

b. α> β> γ>X

c. α> γ> β>X

d. α> β>X> γ

328) Hounsfield units are used

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

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

c. In computed tomography to convert the… grey scale (-1000 is for air, 0 for water…)

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

329) In confocal microscopy an image of a certain…

a. Laser light and pin hole

b. Beam of electrons and magnetic focusing

c. Monochromatic light and quantum optics

d. Visible light and inverted optics

330) The molecular mechanism of diffusion is based on

a. Random, thermal walk of molecules

b. Force acting on molecules due to the concentration difference

c. Electrical force acting on changed molecules

d. Collisions of heavier and lighter molecules

331) The osmotic pressure can be described as

a. Pressure difference across selective membrane preventing the electrodiffusional flow

b. Pressure difference across semipermeable membrane preventing the diffusional flow of solute

c. Pressure difference across the semipermeable membrane preventing the diffusional flow of solute

d. Pressure difference across the selective membrane preventing the flow of solute

332) At Nernst equilibrium the electric field causes the migration flow

a. Of magnitude and direction identical as diffusion flow

b. Of magnitude identical but direction opposite to diffusion flow

c. Of magnitude smaller than diffusion flow and direction opposite to the diffusion flow

d. Of magnitude bigger than diffusion flow and direction opposite to diffusion flow

333) when comparing simple diffusion and facilitated diffusion the right conclusion is

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

b. there are no differences between both flows

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

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

334) Sodium Potassium pump is an active transport mechanism because

a. Ions are transported in the direction opposite to concentration gradient

b. The amount of charge transported into the cell is not equal to that transported outwards

c. Transport is driven by energy obtained from ATP hydrolysis

d. All answers are right

335) Comparing the membrane permeability for different ions in the.. one can write

a. PX>PNa and PX>PCl

b. PX>>PCl and PX>PNa

c. PNa>>PX and PX > PCl

d. PX <PNa and PX>>PCl

338) Functional components of ligand-gated channels are

a. Voltage sensor, ligand binding site, activation filter

b. Voltage sensor, ligand binding site, selectivity filter

c. Ligand binding site, activation gate, selectivity filter

d. Voltage sensor, activation gate, selectivity filter

340) Depolarization phase of action potentials of different cells may be caused by

a. Sodium or potassium currents

b. Sodium or calcium currents

c. Potassium or calcium currents

D. All of the above

Biophysics

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