How are molecules transported across the plasma membrane?

How are molecules transported across the plasma membrane?

Facilitated diffusion is a process by which molecules are transported across the plasma membrane with the help of membrane proteins. A concentration gradient exists that would allow ions and polar molecules to diffuse into the cell, but these materials are repelled by the hydrophobic parts of the cell membrane.

How are nonpolar molecules transported in a cell?

Nonpolar molecules (ex: CO2 & O2) move across the lipid bilayer down the concentration gradient diffusion Large molecules such as glucose move down the concentration gradient with the help of proteins facilitated diffusion Diffusion of water molecules through the cell membrane down (with) the concentration gradient osmosis

How does active transport work against an electrochemical gradient?

The electrical and concentration gradients of a membrane tend to drive sodium into and potassium out of the cell, and active transport works against these gradients. To move substances against a concentration or electrochemical gradient, the cell must utilize energy in the form of ATP during active transport.

How are large molecules move down the concentration gradient?

Large molecules such as glucose move down the concentration gradient with the help of proteins facilitated diffusion Diffusion of water molecules through the cell membrane down (with) the concentration gradient osmosis Movement of substances against the concentration gradient; requires energy

How is a proton gradient used in membrane transport?

A proton gradient is an interconvertible form of energy that can ultimately be used by the transport protein to move particles across the cellular membrane. 2

How does sodium thiopental diffuse across the membrane?

Sodium Thiopental Structure at right), can diffuse across the membrane. 8 Sodium thiopental is a barbiturate frequently used in the methods of lethal injection. 9 Sodium thiopental is a negatively charged particle and proceeds across the blood brain barrier to neuronal synaptic clefts.