Embed Size (px)
DESCRIPTION
Active transport usually happens across the cell membrane. There are thousands of proteins embedded in the cell's lipid bilayer. Those proteins do much of the work in active transport. They are positioned to cross the membrane so one part is on the inside of the cell and one part is on the outside. 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. One protein that moves glucose will not move calcium (Ca) ions. There are hundreds of types of these membrane proteins in the many cells of your body. Many times, proteins have to work against a concentration gradient. That term means they are pumping something (usually ions) from areas of lower to higher concentration. This happens a lot in neurons. The membrane proteins are constantly pumping ions in and out to get the membrane of the neuron ready to transmit electrical impulses.
Citation preview
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.
