Practice question
Question
During cell fractionation, a researcher identifies:
Fraction X: a semi-fluid material in which numerous reactions needed to maintain the living state occur.
Particle Y: a non-membrane-bound RNA–protein structure found freely in X, attached to rough ER and inside mitochondria and chloroplasts.
How should X and Y be identified?
Explanation
The cytoplasm is the semi-fluid matrix and principal arena of cellular reactions. Ribosomes are non-membrane-bound RNA–protein particles occurring freely in the cytoplasm, on rough ER, and within mitochondria and chloroplasts.