RESULTS AND DISCUSSION

Explain what happens when the toad skin was immersed in Ringer’s Transport.

• Ringer’s solution is made up of NaCl, Cacl2 and

NaHCO2 that is used to isolate organs in vitro.

▫ When Na actively transports to extracellular fluids that lie

beneath the skin, the K will be pumped out.

▫ In the experiment, the skin bag was turned inside put so

that Na are transported from the inside to the surrounding

medium.

▫ The weight decreased, therefore the solution is hypertonic

Explain what happens when the toad skin was immersed in 1:1 ratio of Ringer’s solution:NaCN.

•When the toad skin was immersed, it had an

environment with equal concentrations of Na+.

▫Active transport is still going on, but the movement

of Na+ is going back and forth, thus it is in

equilibrium.

▫ In the set up, movement of molecules still occur but

the concentrations of solutes will stay the same as it

is in the skin bag.

Explain the effect of NaCN in active transport.

•Cyanide inhibits respiration.

▫By inhibiting respiration, you also inhibit active

transport because active transport requires

energy from ATP made in respiration.

▫Since anything that affects respiration, affects

active transport too, because it is an energy

requiring process.

Discuss the principle of active transport.

•Active transport describes what happens when

a cell uses energy to transport individual

molecules across the cell membrane.

▫The liquids in and out of the cells have different

substances.

▫Sometimes a cell has to work and use some energy to

maintain a proper balance of ions and molecules.

Discuss the principle of active transport.

▫Active transport happens across the cell membrane.

▫Proteins are positioned to cross the membrane so one

part is on the outside and one part in on the inside.

▫Only when they cross the bilayer are they able to move

molecules and ions in and out of the cell.

▫The membrane proteins are very specific, many times,

these proteins work against a concentration gradient.