Choose the correct answer
The macrophysics use the laws of classical physics. Our everyday experiences with macrophysical systems show us that their behavior is generally
Deterministic
The stochastic behavior of molecular systems can be transformed into a ... one by increasing the number of participating stochastic events or by limiting the degrees of freedom of the single reactions
Deterministic
Mutation in aquaporin-2 causes diuresis in some patients with
Diabetes mellitus
Water or urea
Diffuse across membranes albeit much more slowly than O2 and CO2
The negative sign in front of D in Fick's law specifies that particles flow
Down their concentration gradient
Pressure and volume are thermodynamic parameters. Their product is expressed in units of
Energy
A cube of ice is added to some hot water in a rigid, insulated container, which is then sealed. There is no heat exchange with the surroundings. What has happened to the total energy and the total entropy when the system reaches equilibrium?
Energy remains constant, entropy remains constant
Which of the following is/are reversible process(es)?
Evaporation of a liquid at constant temperature
The change in the Gibbs free energy for a particular process is -36 kJ. Thus, one can say for certain that the process is
Exothermic
A bacterium, containing sodium ions at a concentration of 0,1 mM lives in a pond that contains sodium ions at 0,005 mM. Evidently, sodium ions are entering the cell by
Facilitated diffusion
The graphs above describe which of the following transport mechanisms?
Facilitated diffusion
The amount if "low-molecular" intracellular iron are kept as small as possible by
Ferritin
The fundamental laws of diffusion were formulated by ... who in 1856 published the first biophysical text
Fick
Cholesterol within membranes functions as a(n) ... through its interactions with both hydrophobic and hydrophilic parts of phospholipids.
Fluidity buffer
Continued LDL uptake converts macrophages into
Foam cells are
... are the unstable, highly reactive compounds that damage lipids, proteins and DNA in our cells
Free radicals
All of the following processes lead to an increase in entropy EXCEPT
Freezing a liquid
Both enthalpy and entropy are combined to calculate the
Gibbs free energy
Due to ATP hydrolysis, the molecule A moves out of the cell. Molecule A then diffuses back into the cell. The energy accumulated into the concentration gradient of A is used to drive the transport of another molecule B into the cell. In the previous question the concentration of molecule B inside the cell must be ... the concentration of molecule b outside the cell
Greater than
A patient who has has a severe hemorrhage accidentally receives a large transfusion of distilles water directly into a major blood vessel. You would expect this mistake to
Have serious, perhaps fatal consequences because the red blood cells would swell and burst
The difference in the heat contents of products and reactants is called
Heat of a reaction
As compared fi the extra cellular space, the intracellular concentrations of axons contain
High K+, low Na+, low Cl-
Inalipidbilayer,... fatty acid tails face each other within the bilayer and form a region that excludes water.
Hydrophobic
If the electrical potential difference across a membrane changes from -70 to -80 mV, we call this change
Hyperpolarization
Iftheconcentrationofsolutesinacellislessthantheconcentrationofsolutes in the surrounding fluid, then the extracellular fluid is said to be:
Hypertonic
Suppose dS and dH ae both negative. The reaction is spontaneous if
IdHI < ITdSI
The action potential is conducted
In an all-or-none manner
In thermodynamic processes which of the following statements is not true
In an isochoric process the pressure remains constant
Chemical and electrical forces can act
In the same or opposite directions
When an inhibitor blocks Na+ active transport, the Intracellular concentration of Na+ ... and water enters osmotically, increasing the cell volume
Increases
A decrease in the resting membrane potential cam be brought about by
Increasing [K+]e
For a given chemical reaction, if there is no work done on or by the reaction, then there must be a change in
Internal energy
According to the laws of thermodynamics all processes occurring in nature are
Irreversible and unidirectional
The conclusion that it is impossible to completely convert heat into work without making any changes in the universe
Is the second law of thermodynamics
Which of the statements below describes the structure of the mitochondrion?
It's inner membrane, called cristae is folded
Suppose the biochemical reaction A ! B has a large and positive change in Gibbs free- energy under physiological conditions. Which of the following is the best estimate for the equilibrium constant?
Keq < 1
Under resting conditions, Na+ and K+ passively diffuse across the membrane through
Leak channels
According to the graph above, the molecule X is: (linear increase: diffusion rate of x into the cell in relation to extracellular concentration of X)
Lipid soluble and hydrophilic
In an irreversible process there is
Loss of heat
Borelli founded a school a school in Pisa of iatro-mathematics and iatrophysics in which the human body was perceived as a(n)
Mechanical machine
Iatro-physics has often been considered as a mechanistic forerunner of
Medical biophysics
The figure below shows the establishment of
Membrane equilibrium potential
The sum of all chemical reactions occurring inside a living cell is called
Metabolism
What is the term for the nutrients that are used by our body?
Metabolites
Two kinds of physical behavior meet at the molecular level of biological structures. On the one hand there are stochastic ... processes based on the individual behavior of atoms, molecules or supramolecular structures. On the other hand, there are ... processes based on the behavior of "large" bodies
Microphysical, Macrophysical
"Cristae" are found in which of the following cell organelles?
Mitochondrion
In contrast to isotropic systems like simple solutions in anisotropic systems, the ... or molecules in various directions is not identical but it is restricted in some directions and promoted in others
Mobility
The activity of the antioxidant defense system in the brain is
Moderate
... adhere to functionally deranged endothelium and then enter the intima, where they develop into macrophages
Monocytes
The word thermodynamics stems from two Greek words meaning
Movement of heat
When the potential difference across a membrane of a neuron equals the threshold potential,
Muscle relaxation will occur
The equilibrium potential of an ion
Must be determined experimentally
The balanced half-reaction for the reduction of nicotinamide adenine dinucleotide (NAD+) is
NAD+ + H+ + 2e —> NADH
The electrons that are transferred through the mitochondrial electron transport system initially belong to
NADH and FADH2
Because of it's large conductance, ... is often the dominant ion that determines the resting membrane potential
Na+
The membrane of a typical resting neuron is largely impermeable to
Na+
The dependence of resting membrane potential on ionic permeability and concentration is given quantitatively by
Nernst equation
In response to a stimulus, if the equilibrium membrane potential becomes more negative than the resting potential, we say that the membrane is
Non polarized
The resting membrane potential occurs because
Of the different ions concentrations across the membrane and the different membrane permeability to those ions
According to the second law of thermodynamics
One form of energy cannot be completely converted into another form
Facilitated diffusion can be carried by carriers and channels. These transporters permit net movement of molecules
Only down their electrochemical gradient
The spike of the action potential is caused by
Opening of the voltage gated Na+ channels
Which of the following membrane activities does NOT require the expenditure of external energy by the cell?
Osmosis
Which of the following transport mechanisms involves movement of water?
Osmosis
Heat flow is considered negative when heat flows ... a system, work is considered positive when work is done ... system
Out of, on
The membrane permeability is defined by the formula
P=Dk/d
Which of the following is an intensive property?
Pressure
Antioxidants
Prevent free radical damage
The maximum information the student gets from a grade Pass/Fail will be:
1 bit
The action potential duration in a typical nerve is about
1 millisecond
What is the molarity of sodium chloride in a solution containing 0,50 moles of sodium chloride in 500 mL of water?
1.0 M
A 10-fold concentration gradient of a monovalent ion such as K+ is equivalent, as a driving force, to an electrical potential difference of
10 mV
Suppose we have four distinguishable particles in one side of a two-compartment container. How many possible ways are there to distribute them between the two sides of the container? Consider container compartments as indistinguishable.
11
In the previous question, how many possible ways are there to distribute the particles between the two distinguishable sides of the container?
16
A block of steel with a mass of 1 kg is at a temperature of 60 C (csteel= 450J/kg/C). It is placed in contact with an identical block of steel at a temperature of 20 C. The heat energy of the combined system in Joules will be changed by
18000
Standard enthalpies occur at
25°C and 1.0 atm
Which of the following is TRUE about thermodynamics?
All of the above
Due to ATP hydrolysis, the molecule A moves out of the cell. Molecule A then diffuses back into the cell. The energy accumulated into the concentration gradient of A is used to drive the transport of another molecule B into the cell. The movement of molecule A out of the cell is an example of which transport?
Primary active transport
Which of the following transport processes is directly linked to ATP hydrolysis?
Primary active transport
The ionophore ... is a small peptide that forms a unique helix diner that spams the membrane, forming a channel pore
Valinomycin
An outstanding scientist in the history of biophysics is the German physicist and physiologist Hermann von helmholtz who laid the foundations for the fundamental theories of
Vision and hearing
The plasma membranes of different animal and plant cells contain aquaporins through which
Water can flow more rapidly inside the cell than by diffusing through the phospholipid bilayer
Entropy is a statistical measure of
disorder of a system
During the 1780s, Luigi Galvani performed experiments at the university of bologna involving frogs. The physics of electricity was thus studied in direct relationship with phenomena of
electrophysiology
Chemical reactions that absorb heat energy are called ... and have a ...
endothermic, positive
The first law of thermodynamics states that
energy is neither created nor destroyed
Whether a chemical reaction or physical change takes place depends on both the enthalpy and the... of the process
entropy
All of the following statements concerning entropy are true EXCEPT
entropy is zero for elements under standard conditions
Of the following, only ... is not a state function
heat
The energy of random molecular motion is called
heat
In an exothermic chemical reaction
heat is released as the reaction proceeds
In all irreversible processes, under the conditions U = const., V = const., n = const., the entropy ... and is ... in the stationary equilibrium
increases, minimum
Which of the following may produce ROS?
industrial chemicals
Increasing energy of light goes in the order
infrared, visible, ultraviolet
Biophysics is a/an ... science somewhere between biology and physics. It is connected with other disciplines, as well, such as mathematics, physical chemistry and biochemistry.
interdisciplinary
The partition coefficient is defined by the following formula
k=cme/ce
Biology claims to be a comprehensive science relating to all functions of ... systems.
living
Information is a form of energy which is called
negentropy
All of the following substances freely diffuse across biological lipid bilayer EXCEPT
nitric oxide
The subjects of biophysics are ... underlying all processes of living systems. Biophysics also studies the interactions of physical factors in physiological functions, which is a special subarea, called environmental biophysics.
physical principles
The above graph represents (linear increase: diffusion rate of x into the cell in relation to extracellular concentration of X)
simple diffusion
The Gibbs free energy provides information about the ... of a chemical reaction
spontaneity
The rate if movement of an ion through an ion-specific channel depends on all of the following EXCEPT
the activation state of the channel
Electric potential is defined as the potential energy of a positive test charge divided by
the magnitude of charge
The nature of biophysics is defined by ... rather than by the applied methods.
the scientific problems and approaches
Cells are said to be polarized because
There is an electrical potential difference across the membranes
Mass flux is defined as the amount of a substance that flows perpendicularly
Through a unit of surface per unit time
Iron is transported in plasma bounded to
Transferrin
The electrophoretic mobility of an ion is defined by the following equation
U = E/v
In a resting neuron the Ek is greater (-75 mV) than 'Em (-60 mV). The consequence is that
There us a net tendency for K+ to leak from the cells
Entropy is a function of
Thermodynamic probability
Which class of enzymes is NOT an oxidoreductase
Aldehyde dehydrogenase
A patient suffering from renal insufficiency has a plasma [K+]e = 7 mM. The equilibrium membrane potential for this ion will change to
- 92,6 mV
The change in the internal energy of a system that releases 15.0 J of heat and does 4.8 J of work on the surroundings is
-19,8 J
The standard enthalpy for the reaction 2Na2O2 (s) + 2H2O —> 4NaOH (s) + O2 (g) is dHo = -126 kJ. How much heat is released if 2 moles of NaOH are produced?
-252 kJ
The surface area of a spherical cell with a diameter of 10 microm is
3,14 x 10^-6 cm2
A 10-fold concentration gradient of Ca2+ can be balanced as a driving force by an electrical potential difference of
30 mV
The normal internal temperature of our bodies is 37 C. What is this temperature when expressed in units of Kelvins to the nearest power of ten?
310
(Na+ - K+) -ATPase exchanges
3Na+ for 2K+
If 5 J of energy is added to a system that does no external work, by how much will the internal energy of that system be raised?
5 J
The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is:
7900 J
Let us consider a crystal containing eight atoms at three different temperatures. If enough energy is added to the crystal to start just one of the atoms vibrating, the thermodynamic probability W will be
8
On the graph given below, global equilibrium is represented by
A
When a C-H bond is cleaved homolytically, the resulting intermediate is called
A carbocation
Conduction velocity is increased by
A myelin sheath
The second law of thermodynamics states that the total entropy of a closed system always increases dS ≥ 0, with dS = 0 only in the special case of
A reversible process
The best described cot ran sport system involving glucose and sodium is
A symport
Consider the following reactions: ATP4- + H2O ! ADP3- + H+ + HPO4 2-. Which of the following best predicts a pH increase of the equilibrium mixture?
ADP concentration increases
Which molecule is considered to be the energy currency of cells?
ATP
The brief electrical impulses produced by electrically excitable cells are called
Action potential
The movement of ions against the concentration gradient is
Active transport
A process in which the working substance neither receives nor gives heat to its surroundings during expansion or compression is called
Adiabatic process
The (Na+-K+)-ATPase is
An antiporter
In a Donnan equilibrium
An electrical potential difference is established because no ions can cross the membrane
Naturally occurring spontaneous irreversible processes, such as biological processes, always result in
An increase in entropy
Ice kept in a well insulated container is an example of which system?
An isolated system
Biological membranes as highly organized ... structures are always attractive subjects for biophysical investigations
Anisotropic
Phospholipids
Are found primarily in cell membranes in the body
Molecules, which have a very low partition coefficient
Are poorly absorbed because they cannot dissolve in the lipid membrane
... and alpha tocopherol may cooperate to minimize the rate of lipid peroxidation
Ascorbic acid
In comparison with mediated transport, transport through channels occurs
At the same rate
... bind to the external surface of (Na+-K+)-pump, thereby inhibiting transport
Cardio tonic steroids
The concentration of CO2 in the cell membrane near the intracellular side is higher than its concentration in the membrane near the extracellular side. CO2 will
Be transported into the cell
Which of the following describes the energy supply for facilitated diffusion?
Both a and b
Which of the following are forms of carrier-mediated transport?
Both facilitated diffusion and carrier-mediated active transport
Faraday's constant is measured in
C mol^-1
Active transport has all of the following characteristics EXCEPT it
Can occur without a carrier protein
Which of the following would be considered an age-related disease?
Cardiovascular disease
Ionophores include
Channel-forming and mobile antibiotics that act by passive transport
When the voltage-gated ion channels open, ions move through these channels under the influence of the
Combined effect id the electrical potential difference and the concentration gradients of the ions
The first law of thermodynamics states that energy is
Conserved during any process
In an isolated system during irreversible transformations, the Helmholtz free energy
Decreases until reaching some minimum value
A decisive stimulus has been given to biophysical research through the discovery of x-rays. It was attributable to close cooperation between physicists, biologists and medical scientists which laid the foundation of ... which made significant contributions to the growth of modern molecular biology
Radiation biophysics
The overall enthalpy of the reaction NH4NO3 —> N2O + 2H2O is dH = -36 kJ. This means that the decomposition of 1 mole of ammonium nitrate
Releases 36 kJ of heat
Faciliated diffusion
Requires a transmembrane protein
Active transfer differs from passive transport in that it
Requires external energy usually in the form of phosphate anhydride bonds
Which one of the following correctly indicates the relationship between the entropy of a system and the number of different arrangements, W, in the system?
S = k lnW
For a typical value of the resting potential of -80mV, the driving force on Na+ is ... that on K+
Same as
When a gas is in thermal equilibrium stat A, it has a definite entropy SA, which is a function of n, V, U. Due to the removal of a separator between the gas and the rest of the container, the system will irreversibly reach a new equilibrium state B, which has entropy Sb. The second law of thermodynamics says:
Sb>Sa
The sodium dependent transport of glucose is an example of
Secondary active transport
Some water is believed to criss membranes by
Simple diffusion
Simple diffusion may involve the movement of ... through the plasma membrane down a concentration gradient
Small nonpolar molecules
Biological membranes are normally permeable to
Small, hydrophobic molecules
At rest, the membrane potential is close to the Nernst Ian potential for
Sodium
The resting membrane potential of a neuron depends on
Sodium and potassium ions
In the cotransport of glucose and sodium ions
Sodium ions are transported down their concentration gradient
At rest, the ion distribution inside and outside of a neuron is such that ... ions are most abundant outside the cell, while ... ions are most abundant inside the cell
Sodium, potassium
Which of the following properties describes active transport but NOT facilitated diffusion?
Substances are transported against a concentration gradient
The absorption of glucose from the small intestine generally occurs via
Symport transport with Na+
The gibbs free energy is the maximum useful work (excluding PV work associated with volume changes of a system) that a system can do on the surroundings when the process occurs reversibly at constant
Temperature and pressure
The transfer of uncharged particles is due to
Temperature gradient
Numerous experiments have demonstrated that the immediate energy source for the resting membrane potential is
The active pumping of ions
The rate of diffusion is defined as
The amount of substance transferred per unit cross-sectional area
Ions are driven by their gradient of
The chemical potential
If the ion mobilities are the same,
The diffusion potential will be maximum
The Nernst Equation is used to find
The effect of changing ion concentration on the membrane potential
The thermodynamic force for electric current is
The electric potential gradient
The proton-motive force can be described as:
The energy storage as a combination of a proton and voltage gradient across the membrane
The second law of thermodynamics states that
The entropy of the universe is continually increasing
According to the Henderson equation, if there is no concentration gradient
The equilibrium membrane potential will be zero
Based on his physiological studies, Robert Mayer was able to formulate
The first law of thermodynamics
When 1.0 mole of ZnO (s) decomposes, dH = 348 kJ/mol. What does this tell you about the formation of ZnO (s)?
The formation of ZnO (s) is endothermic
Which of the following involves a decrease in entropy?
The freezing of liquid water into ice
A system does no work even when heat is added to it. Which of the following may happen to the system?
The internal energy of the system increases
The ionic current through a membrane is proportional to the difference (Em-Eeq) the constant of proportionality being
The ionic conductance
Which of the following laws of physics has become the foundation of thermodynamics?
The law of conservation of energy
Of the following product-favored processes, which are endothermic?
The melting of ice at temperatures greater than 0 C, C only
The electric field strength is equal to
The negative electric potential gradient
A sphere is rolling downhill. The driving force for this spontaneous movement is:
The negative gradient of the potential energy
In most axons, the myelin sheath is interrupted at intervals of about 1 millimeter of more. These interruptions are called
The nodes of Ranvier
The chemical properties of the elements are mainly due to
The number and distribution of the outer electrons
the subscript m of the phenomenological coefficient Lmn shows
The number of the corresponding flux.
The first reaction in the prolongation stage of lipid peroxide is
The reaction between s lipid and oxygen
The resting membrane potential of neurons mainly depends on
The resting membrane permeability to organic ions
In the equation X = -grad Ep, where X is a force vector and Ep is the gravitational potential energy, the sign minus shows that
The spontaneous movement occurs from a position with a higher potential energy to one with a lower potential energy.
We define a stationary state as a state in which
The structure and parameters of the system are time independent
A gas is enclosed in a metal container with a moveable piston on top. Heat is added to the gas by placing a candle flame in contact with the container's bottom. Which of the following is true about the temperature of the gas?
The temperature will go up no matter what happens to the piston
The mobility of uncharged particles can be defined as
The velocity of particles per unit force
The equilibrium potential of an ion is the potential
Which just balances the concentration gradient of the ion across the membrane
if the Gibbs free energy change of the reaction A ! B under standard conditions is dG0 = -50 kJ/mol, then the reaction
Will proceed spontaneously from left to right
the electron transport chain components involved in oxidative phosphorylation are located
Within the inner mitochondrial membrane
Which of the following is NOT a state variable
Work
Biophysics studies ... of biological organization, from molecular processes to ecological phenomena.
all levels
If a chemical reaction is spontaneous, the total entropy of the chemical system and its surroundings
always increases
Thermodynamic work is the product of
an intensive property and change in an extensive property
The word ... was invented by a synthesis of "biology" and "technics" at a conference in Dayton, USA, in 1960
bionics
Cybernetics deals with ... in men and machines
control and communications
Mathematically, the rate of free energy transfer can be expressed as
dG / dtdA
For a process at equilibrium, it is always true that
dG = 0
When a spontaneous process takes place, which one of the following is always positive?
dS surroundings
If entropy is exported out of the system then
dSe > 0
The entropy production in a system is given by the following term
dSi / dt
Thermodymically reactions are favorable if
dU < 0
For an isolated system the change in internal energy according to the 1st law of thermodynamics is
dU = 0
Because the internal energy U is a state variable and depends only on the state of the system but not on how the system has achieved the state, we can write
dU = U2 -U1
If a particular amount of charge dq is transported against an electric force, then the electric work done is:
dW = φdq
The change in enthalpy is the change in heat energy of a reaction and is calculated by
∑ (heat content of the reactants) -∑ (heat content of the reactants)
