osmosis Flashcards
What is osmosis?
Osmosis is the net movement of water molecules from a region of lower solute concentration to a region of higher solute concentration.
Why does osmosis occur?
Osmosis occurs because solutes dissolve by forming intermolecular bonds with water molecules, restricting the movement of water. This creates a lower concentration of free water molecules in regions of higher solute concentration.
Is osmosis an active or passive process?
Osmosis is a passive process, meaning it does not require energy.
Can water molecules pass through cell membranes?
Yes, water molecules can pass through cell membranes because they are small enough and hydrophilic (water-attracting), allowing them to move freely in and out of most cells.
What are aquaporins?
Aquaporins are specialized water channels in some cells that greatly increase membrane permeability to water. They allow water molecules to pass through more efficiently, such as in the kidney nephron and plant roots.
How does the aquaporin channel facilitate water movement?
At its narrowest point, the aquaporin channel is only slightly wider than a water molecule, so water passes through in single file. Additionally, the positive charges at the narrow point prevent H+ ions from passing through.
Why do water molecules move towards regions of higher solute concentration during osmosis?
Water molecules move toward areas of higher solute concentration because those areas have fewer free water molecules due to the solutes forming intermolecular bonds with water, creating a gradient that encourages water to flow towards the more concentrated area.
