How do transcription and translation differ?

Why

In a eukaryotic cell, RNA polymerase transcribes a gene into a primary RNA that may be capped, spliced and polyadenylated before export. Ribosomes then read the mature transcript to synthesize protein, after which folding, localization, modification and degradation determine its function. For example, stress can increase a transcript while translation is suppressed, producing less protein than expected.

To test regulation, measure mRNA with RT-qPCR or RNA-seq and protein with an appropriate immunoassay or targeted proteomics. If catalytic function matters, add an activity assay rather than assuming total protein is active protein. Distinguish the kinetics: mRNA may rise within minutes, whereas stable proteins accumulate slowly.

A cross-sectional correlation cannot by itself identify which step caused the difference. The answer is a sequence of processes, not a rule that doubling RNA doubles functional protein.