Question

What type of membrane proteins are integral proteins that move ions or molecules across plasma membrane?

Answer 1

Answer:

Channel proteins and Carrier proteins

Explanation:

These are type of membrane proteins that transcend the entire length of  phosphoslipid  bi- layer  in the plasma membrane.They facilitate the movement of ions  and molecules across  the walls of the plasma membranes.

Generally, substances like glucose, amino acids, are too large to pass through the phopholipid bilayers. Likewise ions of  potassium, sodium calcium, because of their polarities can not pass through either. They are ferried across the phospholipid by  group of protein structures called channel proteins. Some are also transported across by carrier  proteins.  The process by which these protein structures  aided the  diffusion of substances across the phospholipid bilayer is called Facilitated diffusion.

Channel proteins are pores, that are filled with water molecules with the entrance  well gated.  That is the entrance  is controlled by part in the inner structure  of the protein  which can open or close the pores  like a gate to control the movement of ions across it. e.g Sodium channels are gated for  movement  of sodium ions by voltage or ligands(chemicals) during  nervous  transmission to elicits action potential. Like wise Potassium channels allow  diffusion of potassium ions across the phospholipid bilayers. it gates are shut when sodium channels are open; this  regulate ion exchange.

Their structures are well fixed in shape , specific  to the substance or ions being  transported;and the rate of diffusion  depends on  the like hood of opening of the gate or closure.

Carrier molecules  also in the membranes  do not have a fixed shape, and their transport  direction is determined by the direction of concentration gradients. Thus they can flip on either sides of the membranes to aid diffusion across. Their movement can  be both passive and active, and the rates  of diffusion depends on the number of available carrier proteins in the membrane. They are also specific to the ions they transport.And are not gated,

Therefore these two membrane integral  proteins  facilitate movements of substances across the phospholipild bilayers