Final answer:
Tissue samples for RNA work are kept in liquid nitrogen to prevent RNA degradation by RNases. The ultra-low temperatures inactivate enzymes and help maintain RNA integrity for gene expression studies.
Step-by-step explanation:
We store tissue samples for RNA work in liquid nitrogen to preserve the integrity of the RNA. RNA is inherently unstable and can degrade quickly due to the presence of enzymes called RNases, which are abundant in nature and can even be found on human skin.
These enzymes are challenging to inactivate. By storing samples in liquid nitrogen, we achieve a temperature much lower than -196°C, which effectively halts enzymatic activity and preserves the RNA in its original state. This is essential for accurate gene expression studies. Additionally, RNA must be kept away from RNases during extraction, which involves using buffers and enzymes to protect the RNA and separate it from other cellular components.