Living part of a cell (10)
I believe the answer is:
protoplasm
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">living part of a cell</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for protoplasm that I've seen before include "Living part of a cell" , "Basis of life" , "lively stuff" .)