cell membranes

The two sides of a cell membrane face different environments and carry out different functions.

Cell membranes are asymmetrical. Which of the following is the most likely explanation for the membranes asymmetrical nature?

the concentration gradient; ATP

The force driving simple diffusion is _____, while the energy source for active transport is _____

increasing the percentage of unsaturated phospholipids in the membrane

The membranes of winter wheat are able to remain fluid when it is extremely cold by _____.

small and hydrophobic

What kinds of molecules pass through a cell membrane most easily?

There is random movement of substances into and out of the cell.

When a cell is in equilibrium with its environment, which of the following occurs for substances that can diffuse through the cell?

cell-cell recognition

an animal cell lacking glycoproteins on the external surface of its plasma membrane would likely be impaired in which function?

aquaporins

which of the following allows water ti move much faster across cell membranes?

sodium ions moving down their electochemical gradient provides energy to pump sucrose into cells

which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

passive transport

which of the following processes includes all others?