I don't really understand, please help!
Thank you :)
2007-11-08 14:15:33 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Biology
some molecules are small enough to pass through the membrane, but others are too large , or cant pass through the bilipid layer, so they need gates to allow them in..
=]
2007-11-08 14:20:49 · answer #1 · answered by brazilianlek 3 · 1⤊ 0⤋
The cell membrane (with the noted characteristics which allow for selected passage of various nutrients and molecules) enables the cell to maintain an internal environment that is different from its external environment.
2007-11-08 22:47:18 · answer #2 · answered by Doctor J 7 · 0⤊ 0⤋
Cells have a cell membrane that is selectively preamble because certain molecules need to enter into the cell for life processes to occur.
Some of those things are like water and certain types of energy.
2007-11-09 00:02:40 · answer #3 · answered by Y 3 · 0⤊ 1⤋
the person above me is absolutly correct.
some molecules are just too big to pass through, OXYGEN can cross with NO problem, WATER however, CANNOT cross through this plasma membrane (phospholipid bilayer containing cholesterol and proteins) so the cell uses the PROTEINS to make passages for certain molecules to pass. AQUAPOURINS are the special name given for the proteins that allow a passage across the plasma membrane for WATER.
hope this helps!! good luck girl!!
2007-11-08 22:34:35 · answer #4 · answered by Ash 4 · 0⤊ 0⤋