Biophysics 2

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J. N.

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J. N.

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This flashcard set covers advanced biophysics topics at the university level, focusing on membrane potentials, ion channels, and cellular interactions. It delves into the mechanisms of action potentials, the role of sodium and potassium pumps, and the properties of sound waves and electromagnetic fields. Medical students and researchers will find this set particularly useful for understanding the biophysical principles underlying cellular and physiological processes, as well as the applications of these principles in medical diagnostics and treatments.

Cartes-fiches

Utilisateurs

Langue

Anglais

Catégorie

Médecine

Niveau

Université

Créé / Mis à jour

09.02.2020 / 01.03.2020

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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

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

Find the true statement

a) Spin-lattice interaction is described by T1 relaxation time and spin-spin interaction by T2 relaxation time

b) Spin-lattice interaction is described by T2 relaxation time and spin-spin interaction by T1 relaxation time

c) The intensity of the external magnetic field Bo reduces the T1 relaxation time and increases the T2 relaxation time

d) The intensity of the external magnetic field Bo reduces the T2 relaxation time and increases the T1 relaxation time

e) The increase in the crystal temperature is measured after the 90o pulse

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Biophysics 2

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