Nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome. The repeated units may be short and arranged tandemly (in series) or long and dispersed in the genome. replication The process of making a copy of something. replication fork A Y-shaped point on a replicating DNA molecule where new strands are growing. repressible enzyme An enzyme whose synthesis is inhibited by a specific metabolite. repressor reprimere, to press back, keep back] A protein that suppresses the transcription of a gene.