Question
Which of the following is NOT a part of the plasma membrane of a cell? a. Integral proteins b. Glycoproteins c. Plasma proteins d. Peripheral proteins
Answer
4.6
(262 Votes)
Euan
Elite · Tutor for 8 years
Answer
c
Explanation
The plasma membrane of a biological cell consists of various components namely: integral proteins, glycoproteins, peripheral proteins and phospholipids, among others. Integral proteins are integrated completely into the membrane structure, and their hydrophobic membrane-spanning regions interact with the hydrophobic region of the phospholipid bilayer. Glycoproteins are proteins that have an oligosaccharide chain (glycan) covalently attached to their polypeptide side-chains - they reside in the plasma membrane as well. Peripheral proteins are proteins that adhere only temporarily to the biological membrane with which they are associated. However, plasma proteins, despite their name, are not components of plasma membranes. Instead, they refer to proteins found in blood plasma, the liquid portion of the blood. Therefore, plasma proteins are not a part of plasma membrane of a cell.