The movement of molecules through a membrane by filtration requires __________Blank.
Multiple Choice
atmospheric pressure
hydrostatic pressure
osmotic pressure
barometric pressure
The correct answer and explanation is :
The correct answer is: hydrostatic pressure.
Explanation:
Filtration is the process by which molecules move through a membrane due to a pressure gradient. This movement occurs from an area of higher pressure to an area of lower pressure, and it does not require energy input (ATP) because it is a passive transport mechanism.
Understanding Hydrostatic Pressure in Filtration
Hydrostatic pressure refers to the force exerted by a fluid against a membrane or a boundary. This force is typically generated by blood pressure in biological systems or by gravity in other filtration processes. In the human body, the filtration process mainly occurs in the kidneys, where blood pressure forces water and solutes through the glomerular membrane into the renal tubules for urine formation.
Why Not the Other Options?
- Atmospheric Pressure – This refers to the pressure exerted by the weight of the air above a surface. It does not play a direct role in membrane filtration within biological systems.
- Osmotic Pressure – This is related to the movement of water across a membrane due to a difference in solute concentration. It is the driving force for osmosis, not filtration.
- Barometric Pressure – This is another term for atmospheric pressure, which affects weather and altitude but does not drive filtration across membranes.
Real-Life Example:
- In the kidneys, blood pressure creates hydrostatic pressure that pushes water, glucose, and ions through the capillary walls into the nephron, while larger molecules like proteins remain in the blood.
- Coffee filtration also works on a similar principle, where gravity provides hydrostatic pressure to push water through coffee grounds.
Thus, hydrostatic pressure is the key force behind filtration in both biological and mechanical systems.