Question

what are aquaporins? 13. sodium/potassium pump (2.7) what is the na/k pump and what is its significance to the cell? what is membrane potential or polarity? 14. tonicity (2.8) define osmosis. create a chart and define hypotonic, hypertonic and isotonic.

Explanation:

Aquaporins are membrane - bound proteins that form channels in the cell membrane, facilitating the rapid passage of water molecules across the membrane. The Na/K pump is an enzyme (ATP - ase) that actively transports 3 sodium ions out of the cell and 2 potassium ions into the cell, maintaining the cell's electrochemical gradient which is crucial for functions like nerve impulse transmission and muscle contraction. Membrane potential or polarity is the electrical potential difference across the cell membrane due to the unequal distribution of ions. Osmosis is the diffusion of water across a semi - permeable membrane from an area of lower solute concentration to an area of higher solute concentration. A hypotonic solution has a lower solute concentration than the cell, causing water to move into the cell (cell may swell or burst). A hypertonic solution has a higher solute concentration than the cell, causing water to move out of the cell (cell may shrink). An isotonic solution has the same solute concentration as the cell, resulting in no net movement of water.

Answer:

Aquaporins are membrane - bound water - channel proteins. The Na/K pump is an enzyme that actively transports sodium and potassium ions, maintaining cell electrochemical gradients. Membrane potential is the electrical difference across the cell membrane. Osmosis is water diffusion across a semi - permeable membrane. Hypotonic: lower solute concentration than cell. Hypertonic: higher solute concentration than cell. Isotonic: same solute concentration as cell.