Question

Plasmamembrane is made of

• A. proteins and carbohydrates
• B. proteins and lipids
• C. proteins, lipids and carbohydrates
• D. proteins, some nucleic acid and lipids.

Answer 1

The Correct Option is C

The question requires identifying the primary components that make up the plasma membrane. Let's analyze each component mentioned in the options to determine the correct answer.

Understanding the Plasma Membrane Composition

The plasma membrane, also known as the cell membrane, is a crucial part of a cell. It acts as a barrier and regulates what enters and exits the cell. The plasma membrane is primarily composed of three main types of molecules:

1. Proteins: These are essential for various functions including transport, structure, signaling, and adhesion. Proteins within the membrane can act as channels, receptors, or enzymes.
2. Lipids: The membrane consists predominantly of a bilayer of phospholipids. The hydrophobic (water-repelling) tails and hydrophilic (water-attracting) heads of phospholipids create a stable barrier that separates the cell from its environment.
3. Carbohydrates: These are generally attached to proteins and lipids on the extracellular side of the membrane, forming glycoproteins and glycolipids respectively. They play critical roles in cell-cell recognition and communication.

Explanation of Options

• Proteins and carbohydrates: While they are components of the plasma membrane, the absence of lipids in this option makes it incorrect.
• Proteins and lipids: This option misses out on carbohydrates, which are also a significant component of the membrane.
• Proteins, lipids and carbohydrates: This correctly includes all the major components of the plasma membrane, making it the right choice.
• Proteins, some nucleic acid and lipids: Nucleic acids are not a component of the plasma membrane; they are primarily involved in storing and expressing genetic information.

Conclusion

The plasma membrane is primarily composed of proteins, lipids, and carbohydrates. Therefore, the correct answer is proteins, lipids and carbohydrates.