BIOL 2401 cell transport and permeability

Active transport

Transport of a substance acrosss aselectively permeable membrane that requires ATP

passive transport

Transport of a substance across a selectively permeable membrane that does not require ATP

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration. (moves particles via solids liquids gases)

selectively permeable

a property of cell membranes that allows some substances to pass through, while others cannot

concentration gradient

The concentration of a solute is higher on one side of the membrane than the other

molecular weight

the sum of the atomic weights of all the atoms in a molecule

Osmosis

The movement of water across a selectively permeable membrane from an area of higher concentration to an area of lower concentration. (moves water)

hypertonic solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution (egg example: water exits the egg, causing it to shrink)

Crenate

when a cell shrinks due to water loss

hypotonic solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution (egg example: water enters the egg, causing it to swell)

Filtration

The movement of a substance through a cells plasma membrane from high to low concentration. Requires a carrier molecule and ATP (moves both water and particles)

isotonic solution

two solutions having the same osmotic pressure across a semipermeable membrane (egg example: the water enters and exits the egg, keeping the egg the same size)

Brownian motion

The visible movement of large particles being hit by invisible small molecules.

kinetic energy

energy of motion

what will happen to the speed of movement of dust particles if we add heat

The speed of movement will increase due to the added thermal energy.

methylene blue 320g, potassium permanganate 158g. What can you infer about the diffusion rates?

Methylene blue, being heavier, will diffuse slower than potassium permanganate in a solution.

Increased temperature

Faster diffusion rate

Decreased temperature

Slower diffusion rate

Higher Surface Area: Volume ratio

Increased diffusion rate

Lower Surface Area: Volume ratio

Decreased diffusion rate

The rate at which substances are exchanged

Surface Area

Smaller concentration gradient

will decrease diffusion rate

Larger concentration gradient

will increase the diffusion rate

Relationship between molecular weight and diffusion

lighter=?

faster diffusion rate

Relationship between molecular weight and diffusion

heavier=?

slower diffusion rate