Gene Sequence of DNA or RNA which codes for molecule that has function. Product include: SiRNA, rRNA, miRNA, tRNA, mRNA. Gene Expression, information from a Gene is used in the synthesis of functional gene products. Molecular Levels Level one:1-DNA, 2-TranscriptionLevel Two - 1-RNA, 2-Translation, 3-RNACommon transcription factor motifs- Zinc finger - Helix-loop-helix (HLH) - Leucine zipper (LZ) - HMG box (high mobility group ) - Shared feature - Structurally stable framework - Specific DNA recognizing sequences are correctly positioned, Repression of Transcription Cells also possess negative regulatory elementsMechanisms: - Binding to promoter elements. - Blocking assembly of the preinitiation complex. - Inhibiting binding or functioning of transcriptional activators. - Modifying DNA and its interaction with nucleosomes. Some transcription factors activate some genes and repress others.