Simple Version : nucleotides are chemical compounds that can store information in a certain order, a bit like the binary code. There are 4 different nucleotides (letters), that make up your DNA or Deoxy-ribo Nucleic Acid). Genes are chunks of DNA that makes sense! Genes are ‘transcribed’ into RNA ( Ribo Nucleic Acid- a subtle variation of DNA). The formation of RNA is essential for the manufacture of proteins. Proteins are the biochemical compounds that have functional activity. As an example, hormones are proteins, and hormones can influence your sugar rate or push towards running away in case of danger.
Extremely Simple Version : take a bunch of dispersed letters ( makes no sense), gather them together ( makes no sense), write some nice sentences with them ( maybe i’m understanding something!), these words will flow into your mind, being translated and processed into something you’ll understand ( Yeah!) generating, maybe, an idea or a feeling, pushing towards a certain behavior or biological process.