"My blood is the red sea"
meaning My blood is as red as the red sea.
"Thunder is a drum"
Meaning very loud
My cat is a bunny"
meaning very fluffy,
RNA molecules is produced. RNA polymerase is catalyzed while transcribing DNA molecules into RNAm
The figure of speech I'd like to think is hyperbole
Even though synonyms generally share the same meaning, they might not apply in the same context. So, if you want to use one specific word you should do that instead of trying to find a synonym that doesn't quite fit into the context you've established. An example is if you want to use the sentence "I was mad", meaning "I was angry", you could look for a synonym. One synonym is "absurd". However, this is a different type of mad, meaning crazy instead of meaning angry. "I was absurd" has an entirely different meaning than originally intended. This is why you should always double check the contextual meaning of the synonym you want to use.