Diffusion And Osmosis

Question 1

What explains the additional structural components in the lipid bilayer that assists in transport of water soluble compounds, such as glucose and amino acids across the plasma membrane?

Answer 1

Fluid mosaic model of plasma or cell membrane

Question 2

What is the movement of large molecules across but not through the cell membrane?

Answer 2

Vesicular transport

Question 3

What is the random movement of molecules or ions or small particles in solution toward a uniform distribution throughout available volume?

Answer 3

Simple diffusion

Question 4

Is simple diffusion passive or active transport?

Answer 4

Passive transport

Question 5

What is the principle driving force for passive diffusion of an uncharged solute across the plasma membrane

Answer 5

The difference in concentration

Question 6

Net flux of a molecule is directly proportional to?

Answer 6

The size of the chemical driving force (concentration gradient)

Question 7

If an ion is involved, the met flux is proportional to both what?

Answer 7

The chemical and electrical driving forces (electrochemical gradient)

Question 8

Describe Fick’s law

Answer 8

Rate of diffusion across a plane is proportional to the concentration gradient across the plane and to the area of the plane

Question 9

What causes the diffusion constant to decrease?

Answer 9

Increase in size of the molecule
Decrease in solution temperature
Increase in viscosity of solvent

Question 10

What has the strongest influence on permeability?

Answer 10

Lipid solubility, because most substances in body are hydrophilic and don’t easily cross lipid bilayer

Question 11

What factors are included in the permeability coefficient (P)?

Answer 11

Membrane thickness, diffusion coefficient of solute within membrane, solubility of the solute in membrane

Question 12

What affect does molecule size have on permeability?

Answer 12

The smaller the molecule the faster it penetrates

Question 13

An electrical potential difference across a cell membrane will cause?

Answer 13

Movement of ions even if there is not a concentration gradient

Question 14

Describe osmosis

Answer 14

Movement of water across cell membranes

Question 15

What is the driving force for osmosis?

Answer 15

Osmotic pressure difference acorns cell membrane

Question 16

Osmosis occurs from a solution of _______ to ______

Answer 16

High water concentration to low water concentration

Question 17

Does water move up or down its concentration gradient during osmosis?

Answer 17

Down

Question 18

Osmotic pressure is determined by?

Answer 18

Number of particles dissolved in a solution (the concentration of all solutes)

Question 19

What does the Van’t Hoff equation calculate?

Answer 19

Osmotic pressure in biological systems

Question 20

Osmotic pressure of a solution is directly proportional to?

Answer 20

The osmotic ally effective concentration or osmolar concentration

Question 21

The osmolarity of a solution is determined by?

Answer 21

The concentration of osmotically active particles

Question 22

Water is in steady state balance across cell membranes only when?

Answer 22

Osmolality inside and outside the cell is the same

Question 23

What is the effect of ADH?

Answer 23

Renal retention of water and vascular smooth muscle contraction

Question 24

Define isoosmotic

Answer 24

Total osmotic pressure of solution is equal to that of the cell or another solution (no water movement in or out of cell)

Question 25

Define hyperosmotic

Answer 25

Solution has greater osmotic pressure than the cell or another solution (water moves out of cell and cell shrinks in volume) ICF volume decreases

Question 26

Define hypoosmotic

Answer 26

If the solution has less osmotic pressure than the cell or another solution (water moves into cell and swells in cell volume)

Question 27

Permeant changes are?

Answer 27

Temporary changes in osmotic pressure

Question 28

Transient changes in cell volume occur via?

Answer 28

Response to changes in extracellular concentration of permeant solutes

Question 29

Adding a permeant solute such as urea or glycerol to ECF will do what?

Answer 29

Increase ECF osmolality

Question 30

What is the must abundant lipid in the membrane of cells?

Answer 30

Phospholipids