Biology Diffusion Lab

indicator

a substance that changes color in the presence of the substance it indicates

concentration

amount of a substance in a certain place

hypertonic

higher concentration

the plastic baggie is permeable to which substance?

iodine

which substance moved, the iodine or starch?

iodine moved

hypotonic

lower concentration

diffusion

natural tendency for molecules to move from areas of high concentration to low concentration

does a cell use energy when molecules diffuse in or out of the cell down the concentration gradient?

no

main difference between osmosis and diffusion?

osmosis only occurs with water molecules

osmosis

passage of h20 through a semi-permeable membrane from an area of high concentration to low concentration

is the plastic baggie selectively permeable

yes (because the iodine goes through but not the starch)

what did this lab observe?

the diffusion of a substance across a semi-permeable membrane

why is iodine an indicator?

it changes color in the presence of the substance it indicates