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Biophysics MCQs PMU 1st YR/2nd Sem

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Biophysics mcqs
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Pregunta 1

Pregunta
Action potential of neurons is mainly a result of
Respuesta
  • Na and K
  • Na and Mg
  • Ca and K

Pregunta 2

Pregunta
Strength of ion currents during action potential is related to
Respuesta
  • Duration of hyperpolarisation action potential phase
  • Equilibrium potentials of ions
  • Distance from point of stimulation

Pregunta 3

Pregunta
During action potential which quantity is altered
Respuesta
  • Permeability of membrane for diffusion types of ions
  • Diametric permeability of membrane
  • None

Pregunta 4

Pregunta
Membrane potential operated channels are on
Respuesta
  • active fixed value
  • permanently active
  • active in certain range in membrane potential

Pregunta 5

Pregunta
Mark correct
Respuesta
  • all the ion channels
  • all the ion channels let pass
  • ion flow depends on ion type and membrane potential

Pregunta 6

Pregunta
Ion channel blockers
Respuesta
  • Universal
  • Specific to given channels
  • Chemical substances attached to the channel during action potential

Pregunta 7

Pregunta
Ion channels are filled with
Respuesta
  • water
  • air
  • lipid

Pregunta 8

Pregunta
Action potential is
Respuesta
  • alteration of electric polarity of the membrane when cell moves
  • membrane response to over-threshold irritation
  • nonelectric quantity with chemical nature

Pregunta 9

Pregunta
At physiological condition cell membrane is
Respuesta
  • solid structure
  • gas
  • liquid-crystal structure

Pregunta 10

Pregunta
Membrane hyperpolarization leads to
Respuesta
  • elevation of the membrane potential
  • decrease of the membranes potential
  • alteration of membrane charge sign

Pregunta 11

Pregunta
Membrane depolarization leads to
Respuesta
  • Elevation of membrane potential
  • Decrease of membrane potential
  • Noe

Pregunta 12

Pregunta
Resting potential of cell membrane is measured in
Respuesta
  • Megavolts
  • Volts (v)
  • Millavolts (mv)

Pregunta 13

Pregunta
Action potential duration ten times of
Respuesta
  • seconds
  • milliseconds
  • nanoseconds

Pregunta 14

Pregunta
Which term is not related to action potential
Respuesta
  • Overshoot
  • Entropy
  • Depolarisation
  • Threshold

Pregunta 15

Pregunta
During the action potential
Respuesta
  • cation currents from intercellular to extracellular
  • cation currents from extracellular to intercellular
  • none of above

Pregunta 16

Pregunta
The first law or principle of thermodynamics(TD) is defined for
Respuesta
  • covered TD system
  • closed TD system
  • opened TD system

Pregunta 17

Pregunta
The ionophores are
Respuesta
  • ions used in medicine
  • transport molecules
  • ions after the ion polarisation

Pregunta 18

Pregunta
Blocking of Na/K pump working non-electrogenous in stage
Respuesta
  • make depolarization of cell membrane
  • make hyperpolarisation of cell membrane
  • make no alteration of cell membrane

Pregunta 19

Pregunta
The administration of the blocker tetradotoxin led to alteration of following stage of action potential
Respuesta
  • repolarisation phase
  • shape and type of trace potentials
  • depolarisation phase

Pregunta 20

Pregunta
Electrochemical potential is measured by
Respuesta
  • direct method with non polarized electrodes
  • by the disperse phase velocity in constant electric field
  • direct method- electrophoresis with constant electric field

Pregunta 21

Pregunta
In Boltzmann equation
Respuesta
  • entropy is directly proportional to the temperature
  • entropy logarithmically depends on the thermodynamic probability
  • entropy is directly proportional to the thermodynamical probability

Pregunta 22

Pregunta
The filaments of muscles are based on
Respuesta
  • actin fibers
  • troponin globules
  • myosin fibers

Pregunta 23

Pregunta
In cell membranes are present
Respuesta
  • hydrophobic interactions omly
  • hydrophilic interactions only
  • both types

Pregunta 24

Pregunta
The basic condition for arising of membrane potential
Respuesta
  • 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

Pregunta 25

Pregunta
The classic electrophoresis is performed by
Respuesta
  • a constant current
  • alternated current
  • magnetic field

Pregunta 26

Pregunta
Smooth muscles are two types
Respuesta
  • phasic and tonic
  • tonic and synergic
  • phasic and antagonistic

Pregunta 27

Pregunta
In smooth muscle
Respuesta
  • 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

Pregunta 28

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

Pregunta 29

Pregunta
In order to make ATP (adenosine triphophate) in muscles, creatine phosphate (CP) transfers ________________ to adenosine diphosphate (ADP)
Respuesta
  • Oxygen
  • Phosphate
  • Adenosine

Pregunta 30

Pregunta
A sacromere is part of a
Respuesta
  • Myofibril
  • Myofilament
  • Endomysium
  • Perimysium

Pregunta 31

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

Pregunta 32

Pregunta
As a skeletal muscle contracts
Respuesta
  • 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

Pregunta 33

Pregunta
The period of contraction of a typical ventricular muscle fiber is
Respuesta
  • 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

Pregunta 34

Pregunta
The transverse tubular system of skeletal muscle
Respuesta
  • 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

Pregunta 35

Pregunta
During the plateau (phase 2) of the ventricular action potential
Respuesta
  • 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

Pregunta 36

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

Pregunta 37

Pregunta
The sequence for smooth muscle contraction is....
Respuesta
  • 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

Pregunta 38

Pregunta
The neuron action potential starts with
Respuesta
  • Na+ influx
  • Na+ eflux
  • N+ influx

Pregunta 39

Pregunta
The membrane potential after accessing its maximal valve by constant condition
Respuesta
  • Remain stable in time
  • Decrease exponentially
  • Slowly close resting membrane potential

Pregunta 40

Pregunta
The trans-membrane proteins in difference with peripheral
Respuesta
  • do transversal diffusion
  • have hydrophilic and hydrophobic parts
  • possess mainly enzymes activity

Pregunta 41

Pregunta
The most punctual definition of membrane potential valve is defined with the equation of
Respuesta
  • Goldman
  • Nernst
  • Bernstein

Pregunta 42

Pregunta
Sodium-potassium pump in electrogenic condition
Respuesta
  • depolarized cell membrane
  • repolarized cell membrane
  • hyperpolarized cell membrane

Pregunta 43

Pregunta
TTX tetrodoxin is a blocker of
Respuesta
  • potassium channels
  • sodium channels
  • calcium channels

Pregunta 44

Pregunta
The contraction of striated muscle
Respuesta
  • faster than smooth muscle
  • slower than smooth muscle
  • equal to smooth muscle

Pregunta 45

Pregunta
Thin filaments of muscle
Respuesta
  • Actin fibers
  • Troponin
  • Myosin fibers

Pregunta 46

Pregunta
Striated muscles are characterized
Respuesta
  • perodically alter
  • equal to zero membrane potential
  • stable resting

Pregunta 47

Pregunta
Source of calcium needed for contraction striated muscle (rapid transition)
Respuesta
  • Extracellular
  • Endoplasmic Reticulum
  • Motor Neurons

Pregunta 48

Pregunta
Hyperpolarisation phase of striated muscles
Respuesta
  • Preliminary to the stiulus
  • Repeats twice after each action potential occurs
  • Is missing

Pregunta 49

Pregunta
Mark the correct expression
Respuesta
  • 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

Pregunta 50

Pregunta
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
Respuesta
  • True
  • False

Pregunta 51

Pregunta
Source of calcium needed for contraction striated muscle tissue (rapid transition) is
Respuesta
  • Extracellular
  • Endoplasmic Reticulum
  • Motor Neurons

Pregunta 52

Pregunta
Contraction of smooth muscle is _____________ than that of skeletal muscle
Respuesta
  • slower
  • faster
  • equal

Pregunta 53

Pregunta
The trans-membrane transport (transdiffusion) is similar to
Respuesta
  • A filtration
  • A passive membrane transport
  • An active membrane transport

Pregunta 54

Pregunta
Smooth muscle's slow wave is defined by
Respuesta
  • Concentration of Na+, K+ and Ca2+
  • Concentrations of Na+, K+ and Ca2+ pump
  • Concentrations of Na+, K+ and Na/K pump

Pregunta 55

Pregunta
Order the polarizations according to their time of appearing
Respuesta
  • Ionic, Dipolar, Macrostructural
  • Surface, Dipolar, Ionic
  • Surface, Macrostructural, Dipolar

Pregunta 56

Pregunta
The membrane potential after reaching maximum value
Respuesta
  • Remains constant in time
  • Is altered slowly to submaximal value
  • Decreases to zero

Pregunta 57

Pregunta
The membrane lipids are
Respuesta
  • amphiphilic
  • formed glycocalcs
  • have many transport function

Pregunta 58

Pregunta
The lipids are
Respuesta
  • transmembrane
  • membrane receptor
  • organized in layers

Pregunta 59

Pregunta
The plateau phase of myocardial cells is determined by
Respuesta
  • Concentrations of Ca2+ and Na+
  • Concentrations of Ca2+ and K+
  • Concentrations of Na

Pregunta 60

Pregunta
Membrane potential depends on
Respuesta
  • temparature of the thermodynamic system
  • viscosity of the medium
  • medium's protein/lipid ration
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