Question

What is the thickness of plasma membrane (unit membrane)?

• A. 75 $\mathring{A}$
• B. 100 $\mathring{A}$
• C. 125 $\mathring{A}$
• D. 150 $\mathring{A}$

Answer 1

The correct option is A 75 $\mathring{A}$

• The plasma membrane is approximately 75$\mathring{A}$ in thickness. As with most intracellular membranes,
• it is seen as a trilaminar structure, termed as the unit membrane, with outer darker lines approximately 20$\mathring{A}$ wide and an inner lighter line, approximately 35$\mathring{A}$ wide.
• The structure was elucidated by the use of techniques like transmission electron microscopy and free-fracture. Thus, the correct answer is option A.