Membrane Transport Biology 12 October 9, 2008
Posted by ctorrie in Charles Bloom Life.trackback
Cell Membrane
In the above diagram identify molecule X and state what is unique about its structure.
Give the name of molecule Y. Where would it be synthesized and give two functions for this molecule with respect to membrane transport.
CHAOS 
Well, i originally was going to answer the following, but i didn’t know if my answer is right so im scared.
In the text book Location X is referred to as the Hydrophilic regions and the Hydrophobic region. However i am not certain that is correct. I think that the answer might be that they are phospholipids.
Now im positive im going to get this second part wrong, i have been researching though,
It would be synthesized in the phospholipid bilayer, the top region is a polar group and each of the tails are saturated and unsaturated. Because of a double bond their are kinks in some of the tails, which allows packaging and the movement in the lateral plane of the membrane.
I dont know, i dont really think i answered that question, but oh well it’s worth a shot.
Meghan,
You are correct molecule X is a phospholipid and you are also correct it consists of the round hydrophyllic head and the hydrophobic tails… the heads are exposed to the watery environment of the cytoplasm and the extracellular fluid (fluid outside the cell) where as the tails give the membrane support. Nothing to be scared of ;-). That is what is unique about its structure it has two different regions each of which serve a different purpose to the functioning of the membrane.
Molecule Y is a separate question. What is it? Where would it by synthesized and what are its functions?
Cheers,
Mr. Torrie
Well, Molecule Y is simple a protein molecule. Im pretty sure that the protein molecule has many different functions such as cell-recognition, channel, carrier, receptor and enzymatic. I think those are all part of the same category. Then all of those diffent functions have its own type of synthesis? For example Cell-Recognition, these are glycoproteins unique to the cell. They make up a cellular fingerprint by which cells can recognize one another. Im pretty sure that is how you give an example of synthesis? One molecule (glycoproteins) binding together to make two or more molecules(cellular fingerprint)?
Meghan,
You have a very thorough answer… nice work. In this case because there are no lipids or carbohydrates attached to the protein it is not a receptor protein. It is as you said a channel or carrier protein. Channel proteins are responsible for facilitated transport where no energy is required to move molecules like glucose and amino acids into the cell from high to low concentration. Where are all proteins synthesized?
Awesome job, cheers
hmm, i think all proteins are synthesized in the cell right? more detailed, the golgi body? im not too sure about that one.
Y is an integral protein.