Bio: cell membrane
Terms in this set (30)
the movement of molecules form areas of higher concentration to areas of lower concentration
When sugar is mixed with water, equilibrium is reached when
the dissolved sugar molecules are evenly distributed throughout the solution.
The rate of diffusion is affected by what?
temperature, size of molecules, and steepness of the concentration gradient.
True or False:The molecules in a solid lump of sugar do not move.
True or False:Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.
Water molecules across the membrane from an area of high concentration to an area of lower concentration
What will pass through a cell membrane most easily?
Small nonpolar molecules
A red cell paced in a hypertonic medium will _________.
True or False:A 5% urea solution is hypertonic to a 10% urea solution.
True or False:I f a cell is placed in an isotonic medium, there will be no net movement of water.
What does facilitated diffusion require?
When does facilitated diffusion occur?
In either direction(in or out) dependjng on the concentration gradient of the molecule
What is facilitated diffusion used to transport?
Sugars and amino acids
True or False:Unlike simple diffusion, facilitated diffusion requires energy expenditure by the cell.
True or False:Facilitated diffusion requires a specific transporter for a specific molecule.
What happens when the acetylcholine recepter sites are not occupied?
The sodium channels remain closed
What happens when the acetylcholine binds to the receptor sites?
The sodium channels open.
When the sodium channels open, it causes what to happen?
Sodium ions to diffuse through and enter the cell.
True or False:The sodium channels in the cell membrane have receptor sites for acetylcholine.
True or False:The sodium channels in the cell membrane have receptor sites for acetylcholine. This channel is formed by a channel protein.
What does the sodium-potassium pump function to pump?
Sodium ions out of the cell and potassium ions into the cell.
What is the source of energy used to power the sodium-potassium pump?
Breakdown of ATP
During one cycle, the sodium-potassium pump binds and moges what?
3 Na+ and 2 K+
True or False:The sodium-potassium pump is a trans-membrane protein.
True or False:The binding and release of sodium or potassium ions are due to conformational changes in the protein.
What are Phagocytes not attracted to?
In Phagocytosis the digested contents are eliminated by what?
What does a lysosome contain?
Contains lysozyme and proteases which digest bacteria.
True or False:Complement factor C3b coats a bacterium and binds to C3b receptors on Phagocytes, making the bacterium more suseptible to being phagocytized.
True or False:A phagosome containing the engulfed bacteria combines with a lysosome containing enzymes to produce a phagolysosome.