Question 1

Fick’s second law of diffusion follows from the first law if you apply

Accepted Answer

A)  The continuity equation 
B)  Poiseuille’s equation 
C)  LaPlace’s Law 
D)  The conservation of mom entum 
E)  The random walk 
A)  The continuity equation 
B)  Poiseuille’s equation 
C)  LaPlace’s Law 
D)  The conservation of mom entum 
E)  The random walk A

Question 2

The major reason that the apparent diffusion coefficient of Ca2+ in muscle cell cytosol is much lower than in water is that

Accepted Answer

A)  The cytosol is more viscous than water 
B)  The re are obstacles to the free movement of Ca2+ in the cytosol that aren't present in water 
C)  Cytosol contains fixed proteins that bind Ca2+, slowing its movement 
D)  The cytosol moves most electrolytes, but not Ca2+, around by convection 
E)  Ca2+ causes solidification or gelling of the cytosol 
A)  The cytosol is more viscous than water 
B)  The re are obstacles to the free movement of Ca2+ in the cytosol that aren't present in water 
C)  Cytosol contains fixed proteins that bind Ca2+, slowing its movement 
D)  The cytosol moves most electrolytes, but not Ca2+, around by convection 
E)  Ca2+ causes solidification or gelling of the cytosol C

Question 3

Which of the following are appropriate units for a diffusion coefficient?

Accepted Answer

A)  cm s-1 
B)  Joules s-1 
C)  N s-1 
D)  cm 2 s-1 
E)  cm 3 s-1 
A)  cm s-1 
B)  Joules s-1 
C)  N s-1 
D)  cm 2 s-1 
E)  cm 3 s-1 D

Question 4

Diffusion of a small non-electrolyte (D = 0.5 x 10-5 cm2s-1) across a 50 µm cell takes about

Accepted Answer

A)  2.5 milliseconds 
B)  25 milliseconds 
C)  2.5 seconds 
D)  25 seconds 
E)  250 seconds 
A)  2.5 milliseconds 
B)  25 milliseconds 
C)  2.5 seconds 
D)  25 seconds 
E)  250 seconds

Question 5

In the random walk derivation of Fick’s Second Law, the diffusion coefficient was equated to

Accepted Answer

A) $ \lambda^{2} / 2 t_{c} $ B) kt /$\beta$ C) $\lambda$ / tc D) $ \lambda^{2}$ / E) tc / $\lambda$ A) $ \lambda^{2} / 2 t_{c} $ B) kt /$\beta$ C) $\lambda$ / tc D) $ \lambda^{2}$ / E) tc / $\lambda$

Question 6

If Ca > Cb and a > b, where a and b are x-coordinates, then

Accepted Answer

A)  The gradient of C is negative and diffusive flux is positive, going from a to b 
B)  The gradient of C is positive and diffusive flux is negative, going from a to b 
C)  The gradient of C is negative and diffusive flux is negative, going from b to a 
D)  The gradient of C is positive and diffusive flux is negative, going from a to b. 
E)  The gradient of C is negative and diffusive flux is positive, going from b to a. 
A)  The gradient of C is negative and diffusive flux is positive, going from a to b 
B)  The gradient of C is positive and diffusive flux is negative, going from a to b 
C)  The gradient of C is negative and diffusive flux is negative, going from b to a 
D)  The gradient of C is positive and diffusive flux is negative, going from a to b. 
E)  The gradient of C is negative and diffusive flux is positive, going from b to a.

Question 7

Consider two spherical cells that are identical in all respects except that cell one has a radius that is 20% greater than the radius of cell 2 (r1 = 1.2 r2). One substance is transported into the cell pass ively. The relative flux of the material across the membranes of the two cells is given as

Accepted Answer

A)  J1 = 1.2 J2 
B)  J1 = 1.44 J2 
C)  J1 = J2 
D)  J1 = 1.728 J2 
E)  Cannot be determined from the information given. 
A)  J1 = 1.2 J2 
B)  J1 = 1.44 J2 
C)  J1 = J2 
D)  J1 = 1.728 J2 
E)  Cannot be determined from the information given.

Question 8

If the gradient of the flux is negative, it means that

Accepted Answer

A)  The concentration at the point where the gradient is negative must be increasing with time. 
B)  The concentration is at steady state. 
C)  The flux is positive. 
D)  The concentration at any point is decreasing with distance. 
E)  The concentration is constant. 
A)  The concentration at the point where the gradient is negative must be increasing with time. 
B)  The concentration is at steady state. 
C)  The flux is positive. 
D)  The concentration at any point is decreasing with distance. 
E)  The concentration is constant.

Question 9

According to the Stokes-Einstein equation, if the radius of one particle is twice the radius of a second particle ( r1 = 2 r2) , then the relative value of their diffusion coefficients should be

Accepted Answer

A)  D 1 = 2 D2 
B)  D 1 = D2 / 2 
C)  D 2 = D2 / 4 
D)  D 1 = D2 / 8 
E)  D 1 = D2 / 16 
A)  D 1 = 2 D2 
B)  D 1 = D2 / 2 
C)  D 2 = D2 / 4 
D)  D 1 = D2 / 8 
E)  D 1 = D2 / 16

Question 10

The diffusion coefficient of Na+, K+ and many more solutes is slower in cytosol than in water because

Accepted Answer

A)  The cytosol is more viscous than water 
B)  There are obstacles to the free movement of ions in the cytosol that aren’t present in water 
C)  Cytosol contains fixed proteins that bind ions, slowing their movem ent 
D)  The cytosol moves most electrolytes around by convection 
E)  Ca2+ causes solidification or gelling of the cytosol 
A)  The cytosol is more viscous than water 
B)  There are obstacles to the free movement of ions in the cytosol that aren’t present in water 
C)  Cytosol contains fixed proteins that bind ions, slowing their movem ent 
D)  The cytosol moves most electrolytes around by convection 
E)  Ca2+ causes solidification or gelling of the cytosol

Question 11

Consider two spherical cells that are identical in all respects except that cell one has a radius that is 20% greater than the radius of cell 2 (r1 = 1.2 r2). One substance is transported into the cell passively. The relative flow of the material across the membranes of the two cells is given as

Accepted Answer

A)  Q 1 = 1.2 Q 2 
B)  Q 1 = 1.44 Q 2 
C)  Q 1 = Q2 
D)  Q 1 = 1.728 Q 2 
E)  Cannot be determined from the information given 
A)  Q 1 = 1.2 Q 2 
B)  Q 1 = 1.44 Q 2 
C)  Q 1 = Q2 
D)  Q 1 = 1.728 Q 2 
E)  Cannot be determined from the information given

Question 12

The Stokes -Einstein equation is valid only if the diffusing particles are

Accepted Answer

A)  At equilibrium (there is no concentration gradient) 
B)  Warm 
C)  Cold 
D)  Spheres 
E)  Newtonian 
A)  At equilibrium (there is no concentration gradient) 
B)  Warm 
C)  Cold 
D)  Spheres 
E)  Newtonian

Exam 4: Diffusion

Fick’s second law of diffusion follows from the first law if you apply

The major reason that the apparent diffusion coefficient of Ca2+ in muscle cell cytosol is much lower than in water is that

Which of the following are appropriate units for a diffusion coefficient?

Diffusion of a small non-electrolyte (D = 0.5 x 10-5 cm2s-1) across a 50 µm cell takes about

In the random walk derivation of Fick’s Second Law, the diffusion coefficient was equated to

If Ca > Cb and a > b, where a and b are x-coordinates, then

Consider two spherical cells that are identical in all respects except that cell one has a radius that is 20% greater than the radius of cell 2 (r1 = 1.2 r2). One substance is transported into the cell pass ively. The relative flux of the material across the membranes of the two cells is given as

If the gradient of the flux is negative, it means that

According to the Stokes-Einstein equation, if the radius of one particle is twice the radius of a second particle ( r1 = 2 r2) , then the relative value of their diffusion coefficients should be

The diffusion coefficient of Na+, K+ and many more solutes is slower in cytosol than in water because

Consider two spherical cells that are identical in all respects except that cell one has a radius that is 20% greater than the radius of cell 2 (r1 = 1.2 r2). One substance is transported into the cell passively. The relative flow of the material across the membranes of the two cells is given as

The Stokes -Einstein equation is valid only if the diffusing particles are

Physical Foundations Ii: Electrical Force Potential Capacitance and Current

Chemical Foundations I: Chemical Energy and Intermolecular Forces

Chemical Foundations Ii: Concentration and Kinetics

Electrochemical Potential and Free Energy

Cell Structure

Dna and Protein Synthesis

Protein Structure

Biological Membranes

Passive Transport and Facilitated Diffusion

Active Transport: Pumps and Exchangers

Osmosis and Osmotic Pressure

Cell Signaling

ATP Production I: Glycolysis

Atp Production Ii: Tca Cycle and Oxidative Phosphorylation

Atp Production Iii: Fatty Acid Oxidation and Amino Acid Oxidation

Origin of the Membrane Potential

The Action Potential

Propagation of the Action Potential

Skeletal Muscle Mechanics

Contractile Mechanisms in Skeletal Muscle

Neuromuscular Junction and Ec Coupling

Muscle Energetics Fatigue and Training

Smooth Muscle

Organization of the Nervous System

Cells Synapses and Neurotransmitters

Cutaneous Sensory Systems

Spinal Reflexes

Balance and Control of Movement

the Chemical Senses

Hearing

Vision

Autonomic Nervous System

Overview of the Cv System and Blood

Plasma and Red Blood Cells

White Blood Cells and Inflammation

The Heart As a Pump

Cellular Basis of Cardiac Contractility

the Cardiac Function Curve

Vascular Function: Hemodynamics

Microcirculation and Solute Exchange

Regulation of Perfusion

Integration of Cardiac Output and Venous Return

Regulation of Arterial Pressure

Mechanics of Breathing

Lung Volumes and Airway Resistance

Gas Exchange in the Lung

Oxygen and Carbon Dioxide Transport

Acid Base Physiology I Bicarbonate Buffers and Respiratory Compensation

Control of Ventilation

Anatomy and Renal Overview

Glomerular Filtration

Tubular Reabsorption and Secretion

Concentration and Dilution of Urine

Mouth and Esophagus

The Stomach

Intestinal and Colonic Motility

Pancreatic and Biliary Secretion

Digestion and Absorption of the Macronutrients

Energy Balance and Regulation of Food Intake

General Principles of Endocrinology

Hypothalamus and Pituitary Gland

The Thyroid Gland

The Endocrine Pancreas

The Adrenal Cortex

The Adrenal Medulla

The Calcitropic Hormones

Calcium and Phosphorus Homeostasis Ii

The major reason that the apparent diffusion coefficient of Ca²⁺ in muscle cell cytosol is much lower than in water is that

Diffusion of a small non-electrolyte (D = 0.5 x 10^-5 cm²s^-1) across a 50 µm cell takes about

If C_a > C_b and a > b, where a and b are x-coordinates, then

According to the Stokes-Einstein equation, if the radius of one particle is twice the radius of a second particle ( r₁ = 2 r₂) , then the relative value of their diffusion coefficients should be

The diffusion coefficient of Na⁺, K⁺ and many more solutes is slower in cytosol than in water because