Question

What reasoning allowed you to make your choice for the previous question(the last question I uploaded) (i.e., "....what type of amino acid would you NOT expect to find in the trans-membrane portion of ....")?

Select one:

a.
A hydrophobic molecule would be attracted to the hydrophobic fatty acids within the phospholipid bilayer

b.
A hydrophilic molecule would be attracted to the hydrophobic fatty acids within the phospholipid bilayer

c.
A hydrophobic molecule would be attracted to the hydrophilic fatty acids within the phospholipid bilayer

d.
A hydrophilic molecule would be attracted to the hydrophilic fatty acids within the phospholipid bilayer

Answer 1

The correct answer is (d) "A hydrophilic molecule would be attracted to the hydrophilic fatty acids within the phospholipid bilayer."

The trans-membrane portion of a membrane protein passes through the hydrophobic region of the phospholipid bilayer, which is made up of hydrophobic fatty acid tails. Therefore, amino acids that are hydrophobic or have hydrophobic side chains, such as alanine, valine, leucine, isoleucine, phenylalanine, tryptophan, and methionine, are typically found in the trans-membrane portion of membrane proteins. On the other hand, amino acids that are hydrophilic or have hydrophilic side chains, such as arginine, lysine, histidine, aspartic acid, glutamic acid, serine, threonine, asparagine, and glutamine, are typically found on the outer or inner surfaces of the membrane, where they can interact with the aqueous environment. Therefore, we would NOT expect to find hydrophilic amino acids in the trans-membrane portion of a membrane protein.

Step-by-step explanation: