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Biophysics mcqs

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Biophysics MCQs PMU 1st YR/2nd Sem

Question 1 of 60

1

Action potential of neurons is mainly a result of

Select one of the following:

  • Na and K

  • Na and Mg

  • Ca and K

Explanation

Question 2 of 60

1

Strength of ion currents during action potential is related to

Select one of the following:

  • Duration of hyperpolarisation action potential phase

  • Equilibrium potentials of ions

  • Distance from point of stimulation

Explanation

Question 3 of 60

1

During action potential which quantity is altered

Select one of the following:

  • Permeability of membrane for diffusion types of ions

  • Diametric permeability of membrane

  • None

Explanation

Question 4 of 60

1

Membrane potential operated channels are on

Select one of the following:

  • active fixed value

  • permanently active

  • active in certain range in membrane potential

Explanation

Question 5 of 60

1

Mark correct

Select one of the following:

  • all the ion channels

  • all the ion channels let pass

  • ion flow depends on ion type and membrane potential

Explanation

Question 6 of 60

1

Ion channel blockers

Select one of the following:

  • Universal

  • Specific to given channels

  • Chemical substances attached to the channel during action potential

Explanation

Question 7 of 60

1

Ion channels are filled with

Select one of the following:

  • water

  • air

  • lipid

Explanation

Question 8 of 60

1

Action potential is

Select one of the following:

  • alteration of electric polarity of the membrane when cell moves

  • membrane response to over-threshold irritation

  • nonelectric quantity with chemical nature

Explanation

Question 9 of 60

1

At physiological condition cell membrane is

Select one of the following:

  • solid structure

  • gas

  • liquid-crystal structure

Explanation

Question 10 of 60

1

Membrane hyperpolarization leads to

Select one of the following:

  • elevation of the membrane potential

  • decrease of the membranes potential

  • alteration of membrane charge sign

Explanation

Question 11 of 60

1

Membrane depolarization leads to

Select one of the following:

  • Elevation of membrane potential

  • Decrease of membrane potential

  • Noe

Explanation

Question 12 of 60

1

Resting potential of cell membrane is measured in

Select one of the following:

  • Megavolts

  • Volts (v)

  • Millavolts (mv)

Explanation

Question 13 of 60

1

Action potential duration ten times of

Select one of the following:

  • seconds

  • milliseconds

  • nanoseconds

Explanation

Question 14 of 60

1

Which term is not related to action potential

Select one of the following:

  • Overshoot

  • Entropy

  • Depolarisation

  • Threshold

Explanation

Question 15 of 60

1

During the action potential

Select one of the following:

  • cation currents from intercellular to extracellular

  • cation currents from extracellular to intercellular

  • none of above

Explanation

Question 16 of 60

1

The first law or principle of thermodynamics(TD) is defined for

Select one of the following:

  • covered TD system

  • closed TD system

  • opened TD system

Explanation

Question 17 of 60

1

The ionophores are

Select one of the following:

  • ions used in medicine

  • transport molecules

  • ions after the ion polarisation

Explanation

Question 18 of 60

1

Blocking of Na/K pump working non-electrogenous in stage

Select one of the following:

  • make depolarization of cell membrane

  • make hyperpolarisation of cell membrane

  • make no alteration of cell membrane

Explanation

Question 19 of 60

1

The administration of the blocker tetradotoxin led to alteration of following stage of action potential

Select one of the following:

  • repolarisation phase

  • shape and type of trace potentials

  • depolarisation phase

Explanation

Question 20 of 60

1

Electrochemical potential is measured by

Select one of the following:

  • direct method with non polarized electrodes

  • by the disperse phase velocity in constant electric field

  • direct method- electrophoresis with constant electric field

Explanation

Question 21 of 60

1

In Boltzmann equation

Select one of the following:

  • entropy is directly proportional to the temperature

  • entropy logarithmically depends on the thermodynamic probability

  • entropy is directly proportional to the thermodynamical probability

Explanation

Question 22 of 60

1

The filaments of muscles are based on

Select one of the following:

  • actin fibers

  • troponin globules

  • myosin fibers

Explanation

Question 23 of 60

1

In cell membranes are present

Select one of the following:

  • hydrophobic interactions omly

  • hydrophilic interactions only

  • both types

Explanation

Question 24 of 60

1

The basic condition for arising of membrane potential

Select one of the following:

  • difference of ion concentration on the two sides of them

  • difference of temperature concentration on two sides of the membranes

  • "one way" permeability of the membrane

Explanation

Question 25 of 60

1

The classic electrophoresis is performed by

Select one of the following:

  • a constant current

  • alternated current

  • magnetic field

Explanation

Question 26 of 60

1

Smooth muscles are two types

Select one of the following:

  • phasic and tonic

  • tonic and synergic

  • phasic and antagonistic

Explanation

Question 27 of 60

1

In smooth muscle

Select one of the following:

  • Only phosphorylated myosin can bind to actin

  • Ca2+ calmodulin causes phosphorylation of myosin light chain kinase(MLCK)

  • Phosphorylated MLCK causes phosphorylation of myosin

  • A, B and C

  • None of the above

Explanation

Question 28 of 60

1

Each globular head group (often called a crossbridge) of a myosin molecule of skeletal muscle contains:

Select one of the following:

  • A binding site for the attachment of troponin

  • A binding site for the attachment of tropomyosin

  • An actin binding site and a myosin ATPase site

  • One site which binds troponin and another which binds tropomyosin

  • A site which is phosphorylated by protein kinase A(PKA), thereby allowing interaction with actin

Explanation

Question 29 of 60

1

In order to make ATP (adenosine triphophate) in muscles, creatine phosphate (CP) transfers ________________ to adenosine diphosphate (ADP)

Select one of the following:

  • Oxygen

  • Phosphate

  • Adenosine

Explanation

Question 30 of 60

1

A sacromere is part of a

Select one of the following:

  • Myofibril

  • Myofilament

  • Endomysium

  • Perimysium

Explanation

Question 31 of 60

1

Differences between striated (skeletal, cardiac) muscle and unstriated (smooth) muscle include:

Select one of the following:

  • only unstriated muscle is innervated by autonomic nervous system

  • only striated muscle exhibits pacemaker activity

  • striated muscle can contract in the absence of extracellular Ca2+, but unstriated muscle cannot

  • only unstratied muscle has gap junctions

  • none of the above are true

Explanation

Question 32 of 60

1

As a skeletal muscle contracts

Select one of the following:

  • The A bands become shorter

  • The I band become shorter

  • Adjacent Z lines become farther apart

  • The H zones don't change in size

  • The M lines become shorter

Explanation

Question 33 of 60

1

The period of contraction of a typical ventricular muscle fiber is

Select one of the following:

  • about the same as that of a typical slow skeletal muscle fiber

  • shorter than that of a typical atrial muscle fiber

  • slightly longer in duration than the action potential in the ventricular fiber

  • slightly shorter in duration than the action potential in the ventricular fiber

  • longer in duration than contraction in any smooth muscle cell

Explanation

Question 34 of 60

1

The transverse tubular system of skeletal muscle

Select one of the following:

  • has a very small lumenal volume and large surface area relative to the cytoplasmic volume and surface area of the fiber

  • propogates action potentials at about the same speed as the surface membrane

  • forms gap junctions with the sacroplasmic reticulum (SR)

  • never comes closer than about 1 micron from the SR membrane

  • does not contain voltage-gated Na+ channels

Explanation

Question 35 of 60

1

During the plateau (phase 2) of the ventricular action potential

Select one of the following:

  • Na+ channels remain open causing the continued depolarization

  • Ca2+ channels are mostly closed

  • K+ permeability of the membrane is greater than when the membrane is at rest

  • Both Ca2+ and K+ permeability of the membrane is lower than when the membrane is at rest

  • none of these

Explanation

Question 36 of 60

1

Contractility (or inotropic state) of cardiac muscle is increased by

Select one of the following:

  • increased stretch of cardiac muscle (e.g increased filling of the heart)

  • increased myoplasmic Ca2+ during systole

  • Ca2+ channel blockers

  • Decreased coronary blood supply

  • Both A and B will increase contractility

Explanation

Question 37 of 60

1

The sequence for smooth muscle contraction is....

Select one of the following:

  • increased cytosolic calcium, which binds to troponin, complex binds with myosin light-chain kinase which uses ATP to phosphorylate myosin cross-bridges, which bind to actin filaments, resulting in contraction

  • increased cytosolic calcium, which binds to calmodulin in cytosol, which binds with myosin cross-bridges resulting in contraction

  • increased cytosolic calcium, which binds to calmodulin in cytosol, which moves tromyosin from blocking active sites on actin filament, which binds with myosin cross-bridges, resulting in contraction

  • increase cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active actin filament, which binds with myosin cross-bridges resulting to contraction

Explanation

Question 38 of 60

1

The neuron action potential starts with

Select one of the following:

  • Na+ influx

  • Na+ eflux

  • N+ influx

Explanation

Question 39 of 60

1

The membrane potential after accessing its maximal valve by constant condition

Select one of the following:

  • Remain stable in time

  • Decrease exponentially

  • Slowly close resting membrane potential

Explanation

Question 40 of 60

1

The trans-membrane proteins in difference with peripheral

Select one of the following:

  • do transversal diffusion

  • have hydrophilic and hydrophobic parts

  • possess mainly enzymes activity

Explanation

Question 41 of 60

1

The most punctual definition of membrane potential valve is defined with the equation of

Select one of the following:

  • Goldman

  • Nernst

  • Bernstein

Explanation

Question 42 of 60

1

Sodium-potassium pump in electrogenic condition

Select one of the following:

  • depolarized cell membrane

  • repolarized cell membrane

  • hyperpolarized cell membrane

Explanation

Question 43 of 60

1

TTX tetrodoxin is a blocker of

Select one of the following:

  • potassium channels

  • sodium channels

  • calcium channels

Explanation

Question 44 of 60

1

The contraction of striated muscle

Select one of the following:

  • faster than smooth muscle

  • slower than smooth muscle

  • equal to smooth muscle

Explanation

Question 45 of 60

1

Thin filaments of muscle

Select one of the following:

  • Actin fibers

  • Troponin

  • Myosin fibers

Explanation

Question 46 of 60

1

Striated muscles are characterized

Select one of the following:

  • perodically alter

  • equal to zero membrane potential

  • stable resting

Explanation

Question 47 of 60

1

Source of calcium needed for contraction striated muscle (rapid transition)

Select one of the following:

  • Extracellular

  • Endoplasmic Reticulum

  • Motor Neurons

Explanation

Question 48 of 60

1

Hyperpolarisation phase of striated muscles

Select one of the following:

  • Preliminary to the stiulus

  • Repeats twice after each action potential occurs

  • Is missing

Explanation

Question 49 of 60

1

Mark the correct expression

Select one of the following:

  • all ion channels let pass ions from extra to intra cellular compartment

  • all ion channels let pass ions from intra to intra cellular compartment

  • ion flow depends on ion type and membrane potential

Explanation

Question 50 of 60

1

The membrane theory of excitation is based on the idea that stimulation of the surface membrane of an excitable cell causes a molecular restructuring that alters the membrane’s permeability and gives rise to transmembranous ion currents

Select one of the following:

  • True
  • False

Explanation

Question 51 of 60

1

Source of calcium needed for contraction striated muscle tissue (rapid transition) is

Select one of the following:

  • Extracellular

  • Endoplasmic Reticulum

  • Motor Neurons

Explanation

Question 52 of 60

1

Contraction of smooth muscle is _____________ than that of skeletal muscle

Select one of the following:

  • slower

  • faster

  • equal

Explanation

Question 53 of 60

1

The trans-membrane transport (transdiffusion) is similar to

Select one of the following:

  • A filtration

  • A passive membrane transport

  • An active membrane transport

Explanation

Question 54 of 60

1

Smooth muscle's slow wave is defined by

Select one of the following:

  • Concentration of Na+, K+ and Ca2+

  • Concentrations of Na+, K+ and Ca2+ pump

  • Concentrations of Na+, K+ and Na/K pump

Explanation

Question 55 of 60

1

Order the polarizations according to their time of appearing

Select one of the following:

  • Ionic, Dipolar, Macrostructural

  • Surface, Dipolar, Ionic

  • Surface, Macrostructural, Dipolar

Explanation

Question 56 of 60

1

The membrane potential after reaching maximum value

Select one of the following:

  • Remains constant in time

  • Is altered slowly to submaximal value

  • Decreases to zero

Explanation

Question 57 of 60

1

The membrane lipids are

Select one of the following:

  • amphiphilic

  • formed glycocalcs

  • have many transport function

Explanation

Question 58 of 60

1

The lipids are

Select one of the following:

  • transmembrane

  • membrane receptor

  • organized in layers

Explanation

Question 59 of 60

1

The plateau phase of myocardial cells is determined by

Select one of the following:

  • Concentrations of Ca2+ and Na+

  • Concentrations of Ca2+ and K+

  • Concentrations of Na

Explanation

Question 60 of 60

1

Membrane potential depends on

Select one of the following:

  • temparature of the thermodynamic system

  • viscosity of the medium

  • medium's protein/lipid ration

Explanation

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