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Biophysics MCQs PMU 1st YR/2nd Sem

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Biophysics mcqs
Med Student
Quiz por Med Student , atualizado more than 1 year ago
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Criado por Med Student aproximadamente 8 anos atrás
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Resumo de Recurso

Questão 1

Questão
Action potential of neurons is mainly a result of
Responda
  • Na and K
  • Na and Mg
  • Ca and K

Questão 2

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

Questão 3

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

Questão 4

Questão
Membrane potential operated channels are on
Responda
  • active fixed value
  • permanently active
  • active in certain range in membrane potential

Questão 5

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

Questão 6

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

Questão 7

Questão
Ion channels are filled with
Responda
  • water
  • air
  • lipid

Questão 8

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

Questão 9

Questão
At physiological condition cell membrane is
Responda
  • solid structure
  • gas
  • liquid-crystal structure

Questão 10

Questão
Membrane hyperpolarization leads to
Responda
  • elevation of the membrane potential
  • decrease of the membranes potential
  • alteration of membrane charge sign

Questão 11

Questão
Membrane depolarization leads to
Responda
  • Elevation of membrane potential
  • Decrease of membrane potential
  • Noe

Questão 12

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

Questão 13

Questão
Action potential duration ten times of
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  • seconds
  • milliseconds
  • nanoseconds

Questão 14

Questão
Which term is not related to action potential
Responda
  • Overshoot
  • Entropy
  • Depolarisation
  • Threshold

Questão 15

Questão
During the action potential
Responda
  • cation currents from intercellular to extracellular
  • cation currents from extracellular to intercellular
  • none of above

Questão 16

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

Questão 17

Questão
The ionophores are
Responda
  • ions used in medicine
  • transport molecules
  • ions after the ion polarisation

Questão 18

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

Questão 19

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

Questão 20

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

Questão 21

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

Questão 22

Questão
The filaments of muscles are based on
Responda
  • actin fibers
  • troponin globules
  • myosin fibers

Questão 23

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

Questão 24

Questão
The basic condition for arising of membrane potential
Responda
  • 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

Questão 25

Questão
The classic electrophoresis is performed by
Responda
  • a constant current
  • alternated current
  • magnetic field

Questão 26

Questão
Smooth muscles are two types
Responda
  • phasic and tonic
  • tonic and synergic
  • phasic and antagonistic

Questão 27

Questão
In smooth muscle
Responda
  • 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

Questão 28

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

Questão 29

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

Questão 30

Questão
A sacromere is part of a
Responda
  • Myofibril
  • Myofilament
  • Endomysium
  • Perimysium

Questão 31

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

Questão 32

Questão
As a skeletal muscle contracts
Responda
  • 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

Questão 33

Questão
The period of contraction of a typical ventricular muscle fiber is
Responda
  • 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

Questão 34

Questão
The transverse tubular system of skeletal muscle
Responda
  • 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

Questão 35

Questão
During the plateau (phase 2) of the ventricular action potential
Responda
  • 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

Questão 36

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

Questão 37

Questão
The sequence for smooth muscle contraction is....
Responda
  • 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

Questão 38

Questão
The neuron action potential starts with
Responda
  • Na+ influx
  • Na+ eflux
  • N+ influx

Questão 39

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

Questão 40

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

Questão 41

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

Questão 42

Questão
Sodium-potassium pump in electrogenic condition
Responda
  • depolarized cell membrane
  • repolarized cell membrane
  • hyperpolarized cell membrane

Questão 43

Questão
TTX tetrodoxin is a blocker of
Responda
  • potassium channels
  • sodium channels
  • calcium channels

Questão 44

Questão
The contraction of striated muscle
Responda
  • faster than smooth muscle
  • slower than smooth muscle
  • equal to smooth muscle

Questão 45

Questão
Thin filaments of muscle
Responda
  • Actin fibers
  • Troponin
  • Myosin fibers

Questão 46

Questão
Striated muscles are characterized
Responda
  • perodically alter
  • equal to zero membrane potential
  • stable resting

Questão 47

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

Questão 48

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

Questão 49

Questão
Mark the correct expression
Responda
  • 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

Questão 50

Questão
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
Responda
  • True
  • False

Questão 51

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

Questão 52

Questão
Contraction of smooth muscle is _____________ than that of skeletal muscle
Responda
  • slower
  • faster
  • equal

Questão 53

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

Questão 54

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

Questão 55

Questão
Order the polarizations according to their time of appearing
Responda
  • Ionic, Dipolar, Macrostructural
  • Surface, Dipolar, Ionic
  • Surface, Macrostructural, Dipolar

Questão 56

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

Questão 57

Questão
The membrane lipids are
Responda
  • amphiphilic
  • formed glycocalcs
  • have many transport function

Questão 58

Questão
The lipids are
Responda
  • transmembrane
  • membrane receptor
  • organized in layers

Questão 59

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

Questão 60

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

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