In cotransport, a single ATP-powered pump that transports a specific solute drives the active transport of several other solutes. Normally, sodium in waste is reabsorbed in the colon, maintaining constant levels in the body, but diarrhea expels waste so rapidly that reabsorption is not possible, and sodium levels fall precipitously. To treat this life-threatening condition, patients are given a solution to drink containing high concentrations of salt and glucose. The solutes are taken up by sodium-glucose cotransporters on the surface of intestinal cells and passed through the cells into the blood. This simple treatment has lowered infant mortality worldwide.
What are the two forces that drive the diffusion of ions across the membrane?
So, there are two forces that drive the diffusion of ions across the plasma membrane—a chemical force (the ions' concentration gradient), and an electrical force (the effect of the membrane potential on the ions' movement).
Why a carrot left on the counter overnight would become limp?
due to the relatively low humidity around the counter, water would diffuse (via osmosis) out of the carrot, down the concentration gradient, this makes the carrot flaccid (limp) as plasmolysis occurs due to the lack of water.
What do ligands have to do with the endocytosis process and is this process an active or passive type of transport?
What do ligands have to do with receptor-mediated endocytosis? A ligand is a molecule that binds specifically to another molecule, usually a larger one. Human cells use receptor-mediated endocytosis to take in cholesterol for membrane synthesis and the synthesis of other steroids.
How can phospholipids with unsaturated hydrocarbon chains affect membrane fluidity?
What affect do phospholipids with unsaturated hydrocarbon chains have on the membrane fluidity? It increases fluidity because of more kinks.
Can I eat old carrots?
When carrots have gone bad, they become mushy and slimy and should not be eaten.
What is Cotransport in biology?
A cotransporter (symporter) is a carrier protein that allows the transport of two different species (a solute and an ion) from one side of the membrane to the other at the same time [44,45]. From: Transport in Biological Media, 2013.
What components does Cotransport involve?
Cotransport involves the hydrolysis of ATP by the transporting protein. A cotransport protein is most commonly an ion channel. Cotransport proteins allow a single ATP-powered pump to drive the active transport of many different solutes. The sodium-potassium pump is an example of a cotransport protein.More items...
How do endocytosis and exocytosis allow movement of materials in and out of the cell?
Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell. Exocytosis describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell.
What functions do endocytosis and exocytosis carry out for the cell?
Endocytosis and exocytosis are the processes by which cells move materials into or out of the cell that are too large to directly pass through the lipid bilayer of the cell membrane.
How do the unsaturated fatty acids of the complex lipids contribute to the fluidity of a membrane?
If unsaturated fatty acids are compressed, the “kinks” in their tails push adjacent phospholipid molecules away, which helps maintain fluidity in the membrane. The ratio of saturated and unsaturated fatty acids determines the fluidity in the membrane at cold temperatures.
Which structural feature of the cell membrane allows molecules such as oxygen and carbon dioxide to diffuse into and out of the cell?
The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.
What effect do double bonds have on phospholipid hydrocarbon tails and on the fluidity of the membrane?
Double bonds have little effect on membrane fluidity. Double bonds increase the ability of hydrocarbon tails to pack together into a rigid mass, which makes the bilayer less fluid. Double bonds increase the ability of hydrocarbon tails to pack together into a rigid mass, which makes the bilayer more fluid.