Passive and Active Transport in Biology

Diffusion requires energy input to move molecules from regions of higher concentration to lower concentrations.

Osmosis involves the movement of water molecules across a semipermeable membrane.

In osmosis, water moves from an area of high solute concentration to low solute concentration.

Diffusion occurs through the random movement of particles.

Active transport relies solely on the concentration gradient between two compartments.

Oxygen diffuses from the bloodstream to the lungs.

_________ is the process of molecular motion from regions of higher concentration to regions of lower concentration.

Diffusion continues until the system reaches _________, meaning both sides have equal concentrations of the substance.

The mechanism behind diffusion is the random motion of molecules, allowing them to spread from areas of high concentration to areas of low concentration through __________.

Osmosis is a special type of diffusion that involves the movement of ________ molecules across a semi-permeable membrane.

Osmosis involves the movement of water molecules from low solute concentration to high ________ concentration.

Water molecules in osmosis follow the concentration gradient of solvents, trying to balance the ________ pressure on either side of the membrane.

Unlike other passive transport processes, dissolved salts usually remain within the cell, creating an excess of solute on one side and solvent (water) on the other. The net flow of water molecules across the selectively permeable barrier is driven by differences in solute concentration between the solutions separated by the membrane. This process is known as ______.

One advantage of passive transport is that it doesn't require energy expenditure, making it an efficient method for the cell to transport substances across its membrane. Additionally, it can facilitate the rapid exchange of molecules between the cytoplasm and the extracellular fluid, allowing for quick adjustments to environmental changes. On the downside, passive transport relies entirely on the concentration gradient of the transported substance. Once the concentration becomes balanced, there is no net flow of molecules, limiting the efficiency of the ______ over time.

Active transport, on the other hand, is a process that requires energy to transport molecules across the cell membrane against their concentration gradient. This energy is derived from adenosine triphosphate (ATP), a molecule that stores chemical energy. Through active transport, cells can establish and maintain concentration gradients of molecules, regardless of their initial concentration difference. This versatility makes active transport an indispensable tool for a wide array of physiological ______.

There are two main types of active transport: primary and secondary. Primary active transport involves the direct binding of ATP to the carrier protein and uses the released energy to actively transport molecules across the membrane. Secondary active transport utilizes pre-existing concentration gradients to drive the transport of other molecules. This process occurs when a carrier protein binds to a substrate and simultaneously releases its bound ATP molecule, using the energy released to transport another solute against its concentration ______.

While active transport provides the ability to move molecules against their concentration gradient, it does so at the cost of energy consumption. Efficient energy conversion is critical to maintain proper functioning, as energy wasteful pathways may disrupt normal cellular activities. Nevertheless, active transport is a key player in many physiological processes, such as establishing electrochemical gradients, maintaining plasma membrane potentials, and ______.

Diffusion occurs through the random movement of particles. Diffusion requires energy input to move molecules from regions of higher concentration to lower concentrations. Oxygen diffuses from the bloodstream to the lungs. In ______, water moves from an area of high solute concentration to low solute concentration. Osmosis involves the movement of water molecules across a semipermeable membrane. Active transport relies solely on the concentration gradient between two ______.