Animal cells maintain a concentration gradient of certain charged particles acro
ID: 3510888 • Letter: A
Question
Animal cells maintain a concentration gradient of certain charged particles across their plasma membranes. The cell pictured here experiences a gradient of positively charged Na+ (sodium) ions, positively charged K+ (potassium) ions, and negatively charged particles collectively referred to as A- (anions).
These three gradients exist because the plasma membrane is _____(1)_______. Only specific charged particles can pass through ___(2)______ protein such as the voltage-gated Na+ channel and only when the channel is open.
(1) Choice: a. selectively permeable b. impermeable to all molecules c. impermeable to non-polar molecules
(2) Choice: a. an active transport b. a peripheral membrane c. a passive transport
Based on the total concentration of charge on each side of the cell, the outside of the cell has __________ positive charge than the inside of the cell. A) More B) Less
Remember that ions are electrically attracted to particles of opposite charge and are repelled by particles of the same charge. By electrical attraction alone, in what direction would K+ tend to move if movement were possible? _______ A) into the cell B) outside the cell
By diffusion alone, in what direction would K+ ions tend to move if movement were possible? A) Out of the cell B). into the cell
If a gated K+ channel in the membrane opened up, in what direction would K+ move? A) Out of the cell B) Into the cell C) Depends on the relative strengths of diffusion and electrical attraction
The tendency of K+ ion to move across the plasma membrane depends on the ___________. A) electrochemical gradient B) Osmotic potential C) turgor pressure.
Voltage-gated K+ channel (closed) Voltage-gated Na+ channel (closed) 1 -Anions (negatively charged proteins, nucleic acids, and other large molecules)Explanation / Answer
Plasma membrane is selectively permeable.
Specific charged particles pass through peripheral membrane.
Outside of the cell has more positive charge.
By electrical attraction, K+ ions move outside of the cell.
By diffusion, K+ ions move outside of the cell.
Relative strengths of diffusion and electrochemical potential.
Electrochemical gradient.