Question

Which of the following cell membrane components serves as recognition signals for interaction between cells
A. Recognition protein
B. Glycolipids or glycoproteins
C. Phospholipids
D. Integral proteins

Answer 1

Cell membrane is composed of bi-layer of phospholipids. The Interaction between cells is an important process for the growth and development of multicellular organisms. They communicate by sending and receiving signals.

Complete answer: Recognition proteins are the protein molecules that are embedded on the cell membrane. These facilitate intercellular communication. These proteins have specific sites known as active sites that have unique sites to fit specific signal molecules. On activation of these recognition proteins by some signal molecules, which can be any hormones, it changes the cell metabolism rate or cellular division.
Considering the other given options:
-Glycolipids or glycoproteins: These structures impart stability to the cell membrane by forming hydrogen bonds with the water molecules around. They also function as receptor molecules that bind to neurotransmitters or hormones.
-Phospholipids: The molecules help in functioning as a barrier to the membrane, controlling the entry and exit of molecules from the cells. The selectively permeable nature of the cell membrane is due to this phospholipid bilayer.
-Integral Proteins: These proteins help in the intercellular transportation of different essential substances. Some integral proteins act as receptors to certain hormones too.
Thus from the above-given options, the most appropriate and correct answer is A, that is, Recognition proteins function as a recognition signal for intercellular interactions.

Note: Many chronic diseases and disorders such as different types of cancers are caused due to defective signaling process or failure in effective intercellular communication. Certain infectious organisms such as certain types of viruses have the capability of interfering with these mechanisms and causing various diseases. Absence of these signals, the cells obtain the ability to grow uncontrollably leading to tumorous growth.