Biophysics 2

To find electrical axis of the heart one should use... 

ECG curve presents the dependence of 

Which type of neurons are typically unipolar? 

The intensity of electrical field is defined as:

Typical value of the electrical field intensity in the biological membrane is: 

Indicate the effect of the outward (from inside towards outside the cell) cations flowing through the cytoplasmic membrane

What happens to the membrane capacitance if its thickness increases two folds( two times)

The current density (j) is defined as

The phenomenon of migration in the electrical field in electrolytes is quantitatively described by:

Apply the Fick’s law to solve the fallowing problem. The flux density J of particles is locally flowing in condition of a local concentration difference C according at the distance X. the distribution of particles changed and the local concentration doubled (2C) at the distance was reduced twice (0,5X). Indicate the value of the flux density after the change of the particle distribution: Ficks law: J= -D (deltaC/deltaX) 

Let us assume that the width of synaptic cleft is 100 nanometers and that diffusion coefficient in neurotransmitter in the electrolyte within the cleft is 10^-9m^2. Indicate how long it will take for the neurotransmitter to diffuse through the cleft (ms is millisecond): t=X2/2D (D=diffusion coefficient=10-9 m2/s in aqueous solution)(X=distance)

For 10nm the time is t=10^-8s, for 100nm time is t=10^-5s

What fenomena contribute to electrodiffusion: 

Sound and ultrasound:

Which tissues in a human’s body have the ability to totally reflect the ultrasound beam because of significantly different value of their acoustic impedance:

Which type of ionizing radiation is produced upon a radioactive decay of natural isotopes:

Which tissue in a human body have the highest value of the mass absorption coefficient for ionizing radiation: - eye and blood has lowest (0,1/0,17)

 A visible light is:

The electric signal generated by a photoreceptor cell upon exposure to a visible light: 

Which physiologically-relevant nuclei listed below are paramagnetic: 

 The sound velocity in air and water are: 

Considering the flow of ideal fluid through cylindric vessel, how much will increase the velocity of the fluid flow if the vessel’s diameter is reduced 3 times (we assume that the pressure including the flow does not change).

If we measure, for the sake of experiment, the blood pressure as a subject in the standing position and the cuff is placed on the leg close to the foot, then the measured values of systolic/diastolic pressures will read:

The phenomenon of viscocity in liquids can be described as fallows:

When a viscous fluid is transported through a cylindrical vessel of constant diameter and under a constant pressure, the fluid velocity:

Parameter Q defines the volume of viscous liquid transported per unit time through a cylindrical vessel. If the radius and the length of the vessel are reduced by 50% how much the parameter Q will change (assuming that all other parameters including pressure and liquid viscosity remain the same)? 

When the laminar flow converts to turbulent one?- turbulent flow happens when v1 is less than v2

The velocity of propgation of the pulse wave along the arterial vessels is: 

The bipolar cells in the retina contains ON and OFF bipolar cells. Choose the proper description of these cell types:

Receptive field of a bipolar cell is: 

What happens to the optical power of a lens if its curvature radii gets 50% shorter? 

For a thick lens (as in the eye) the distance between the image and the lens is measured as:

The optical power of the eye system is approximately: 

The closed system consisting of the ideal gas is expanding (increasing its volume) without exchanging heat with the environment. The internal energy of this system is:

When in the isolated system entropy increases: 

In the equilibrium state: 

In the state of equilibrium in the closed system the free enthalpy (total heat content of a system) dG=F+pv in equaliblrium values of F ang G assum minimal values:

For the open system the chemical potential (μ) for a given compound can be described as:

According to Van’t Hoff’s law:

The considered system can be found in the 2 states: state S1 characterized by the energy U1 and state S2 characterized by energy U2. If U1<U2

Indicate how the energy of interactions between 2 point charges depend on the distance (r) between these charges