Biologlish! Singular nouns, Plural, Adjectives

This new batch (Session 2009/2010) have learnt Science and Mathematics in English since Form One! In a recent quiz, I asked them about the 'nuclear structure' in different types of cell. Most of them couldn't figure out what the he** is this 'nuclear' thing all about (nuclear bomb? nuclear plant? nuclear energy?).
Initially, I was shocked when the supposedly easy questions has become a deep trap for these students in order to get good marks. Good marks will boost their confidence and will encourage them to study earlier. Well, I did have a motivational session mith them soon after!

In the recent session, I became an English teacher, pointing out the different words/terms in English referring to one particular noun (in Biology).
e.g. 1: nucleus (singular) --> nuclei ('noo - clee - eye', plural) --> nuclear (adjective, descriptive word that precede a noun - e.g. nuclear envelope. nuclear material, nuclear pores).
e.g. 2: mitochondrion (s.) --> mitochondria (p.) --> mitochondrial (adj.) - e.g. mitochondrial membranes
e.g. 3: stoma (s.) -> stomata (p.) --> stomatal (adj.) - e.g. stomatal opening
How about these singulars? ...fungus, cell, hormone, bacterium, ...

Until next posting...