Passive Transport

Question 1

Move solutes across the cell membrane without expenditure of energy.

• Diffusion, osmosis, and filteration are examples

Answer 1

Passive Transport

Question 2

The tendency of molecules or ions to move from an area where they are in higher concentration to an area where they are in lower concentration, that is, down or along their concentration gradient

Answer 2

Diffusion

Question 3

• A particle distribution process
• Nonpolar and lipidsoluble substances diffuse directly through the lipid bilayer.
• Such substances include oxygen, carbon dioxide, and fat-soluble vitamins
• This process is based on the tendency of particles (molecules or ions) to scatter evenly throughout the environment in a defined space.
• Eliminates the concentration gradient
• Unassisted diffusion of lipid-soluble or very small particles

Answer 3

Simple Diffusion

Question 4

The difference between the high and low concentrations of the particles

Answer 4

Concentration gradient

Question 5

• When the particles bounce off of each other until they are evenly distributed within the defined space.
• There is no longer a concentration gradient and hence, no net movement

Answer 5

Equilibrium

Question 6

• Refers to how far a particle must move to achieve equilibrium.
• The smaller the ____, the quicker the concentration gradient is eliminated.

Answer 6

Distance

Question 7

• Affects how fast a particle can diffuse.
• The smaller the particle, the faster it moves and therefore the quicker the concentration gradient is eliminated

Answer 7

Particle size

Question 8

• Heat.
• Increase in Kinetic Energy, eliminates concentration diffusion faster

Answer 8

Temperature

Question 9

• Refers to the difference between the areas with the highest and lowest concentration of substance.
• The greater the difference, the steeper the concentration gradient and the faster diffusion proceeds.

Answer 9

Gradient size

Question 10

• Affects how easily a solute can get through the plama membrane.
• Because cell membranes are compromised predominateley of lipids, particles that are ______ _______ such as dissolved gases, steroid hormones, and certain vitamins, can pass freely through the plama membrane.

Answer 10

Lipid solubility

Question 11

• Can either attract or repel certain solutes.

Answer 11

Electrical forces

Question 12

• The diffusion of solvent, such as a water, through a selectively permeable membrane that is freely permeable to water, but not freely permeable to solutes.
• eliminates concentration differences between two compartments much more quickly than diffusion of solutes.

Answer 12

Osmosis

Question 13

• The ability of a solution to cause osmosis of water (movement of water through a membrane)
• SOLUTES SUCK
• Expressed in mmHg
• The force with which water moves through a membrane into a solution with a higher solute concentration (lower water concentration)
• Negative pressure because of dissolved solutes
• “sucks” the water across the membrane

Answer 13

Osmotic pressure

Question 14

The force of pushing against a fluid

Answer 14

hydrostatic pressure

Question 15

• The total concentration of solutes in an aqueous solution, or more specifically, the total number of individual atoms, ions, and molecules in the solution.
• Measured in moles of solute/L of solvent

Answer 15

Osmolarity

Question 16

• The ability of a solution to change the shape or tone of cells by altering their internal water volume
• based on how the solution affects cell volume, which depends on (1) the solute concentration and (2) whether or not the plasma membrane is permeable to the solute.
• “tension”

Answer 16

tonicity

Question 17

• The same tonicity
• Solution with the same concentration of non-penetration solutes as those found in cells
• When a cell is placed in ____ solution, it retains its normal shape, and exhibits no net loss or gain of water.
• For every water molecule that leaves the cell, one replaces it from the solution
• Solutes cannot leave, only water can

Answer 17

Isotonic

Question 18

• A solution that causes water to move inside the cell
• solutions that are more dilute (contain a lower concentration of nonpenetrating solutes) than the cell’s cytoplasm
• when cells are placed in ___ solution, they swell as water rushes into them.
• Distilled water is the most extreme example because it contains no solutes, water continues to enter cells until they finally burst or lyse
• contain less solute (more water)

Answer 18

Hypotonic

Question 19

• Solutions with a higher concentration of nonpenetrating solutes compared to the cytoplasm of the cell
• Solution that contains more solute, less water
• cell looses water by osmosis
• Cell shrinks (crenation)

Answer 19

Hypertonic

Question 20

• Elevated Sodium concentration in the plasma
• when more water is lost than sodium, so the sodium concetration of the plasma increases
• causes the bodu’s cells to shrink
• Shrinkage of neurons results in dysfunction of the central nervous system where sodium and potassium balance are especially crucial.

Answer 20

Hypernatremia

Question 21

• Occurs if one becomes overhydrated with pure water without replacing electrolytes–this dilutes the plasma membrane
• Water moves into cells, causing them to swell

Ex: causes you to act drunk

Answer 21

Hyponatremia

Question 22

• The process that forces water and solutes through a membrane or capillary wall by fluid or hydrostatic pressure.
• Like diffusion, it involves a gradient
• Pressure gradient that pushes solute-containing fluid (filtrate) from a higher pressure area to a lower pressure area

Answer 22

Filtration

Question 23

Transmembrane integral proteins that are specific for transporting certain polar molecules or classes of molecules, such as sugars and amino acides, that are too large to pass through membrane channels.

Answer 23

Carriers

Question 24

Transmembrane proteins that transport substances, usually ions or water, through aqueous channels from one side of the membrane to the other.

Answer 24

Channels

Question 25

* Certain molecules (glucose and other sugars, amino acids, and ions) are transported passively even though they are unable to pass through the lipid bilayer * they move through the membrane * transported substances either (1) binds to protein carries in the membrane and is ferried across or (2) moves through water-filled proten channels

Answer 25

facilitated diffusion

Question 26

Water also moves freely and reversibly through water-specific channels constructed by transmembrane proteins called\_\_\_, which allow single-file diffusion of water molecules.

Answer 26

Aquaporins (AQPs)