Biology, 7Th Grade, Chapter 6

Front 1

Diffusion

Back 1

The net movement of particles of a substance from where they are more concentrated to where they are less concentrated.

Front 2

Equilibrium

Back 2

When molecules are even throughout a space. I.e., # of dye molecules moving one direction = to # moving in another direction.

Front 3

Osmosis

Back 3

The passive transport of water across a selectively permeable membrane.

Front 4

Selectively permeable
"membrane"

Back 4

Allows some substances to cross the membrane more easily than others. Blocks the passage of other substances altogether. i.e. window screen air in/mosquitos out.

Front 5

Membrane

Back 5

All cells, plant and animal, contain a cell membrane that controls what enters and leaves the cell.

Front 6

Passive transport

Back 6

No energy is expended. Only random movement of molecules is necessary to move them across the membrasne. Molecules move from places of higher concentration to lower concentration.

Front 7

Active transport

Back 7

When a cell expends energy to move molecules or ions across a membrane. Specific transport proteins pumps a solute across a membrane, usually opposite from way it travels in diffusion.

Front 8

Endocytosis

Back 8

Cell takes in large particles by engulfing them endo"within" cyto "cell". Substances taken into cell within vesicles that bud inward without passing through the cell membrane. Larger membrane sacs are also formed by endocytosis when food particles are ingested.

Front 9

Exocytosis

Back 9

Exo =external cyto = cell
Reverse of endocytosis. Cells eject waste products (protein products)from inside the cell. Vesicle containing proteins fuses with plasma membrane and spills contents outside the cell.

Front 10

facilitated diffusion

Back 10

"facilitate = to help"
A form of passive transport. Transport proteins "help" transport or diffuse into or out of the cell.

Front 11

hypertonic

Back 11

"hyper" above
In osmosis, a solution with a higher concentration of solute is hypertonic. In saline solution = less water than salt.

Front 12

hypotonic

Back 12

"hypo" below
In osmosis, a solution with a lower concentration of solute is hypotonic. In saline solution = more water than salt.

Front 13

isotonic

Back 13

isos = equal
Solutions in which the concentrations of solute are equal.

Front 14

vesicle

Back 14

Small membrane sacs that specialize in moving products into and out of a cell.

Front 15

Water balance

Back 15

in animal cells: cell gains water and may pop. Aquatic animals require mechanism to get rid of water.

Plants: Cell becomes firm, walls are stronger and pressure keeps plant from taking in too much water. Plant in isotonic enviroment has no water flow and will wilt.

Front 16

Relate diffusion and equilibrium

Back 16

Diffusion is the movement of molecules from more to less concentrated. As diffusion happens, eventually the number of molecules moving in either direction are equal = equilibrium.

Front 17

How does passive transport occur?

Back 17

By random movement of molecules with no energy used.

Front 18

Relate osmosis to solute concentration.

Back 18

Osmosis changes the solute concentration because eventually the higher solute is distributed evenly which becomes isotonic.

Front 19

How is active transport different from passive transport.

Back 19

active transport requires energy and "helper" vesicles.

Front 20

How do large molecules move across a membrane.

Back 20

Unlike small particles, large particles depend on being packaged in veicles (small membrane sacs) that move products in, out and within a cell.