Transcription is a process of duplication of information coded in deoxyribonucleic acid (DNA) by synthesis of an appropriate ribonucleic acid (RNA). Later on this RNA will be used to synthesize proteins. The transcription is performed by RNA-polymerize. During transcription the double spiral of DNA is untwined and RNA is synthesized on one of the strands (so called template strand) of the DNA. In contrast to DNA replication during transcription just some genes are transcribed. The length of the transcribed RNA depends on the length of the protein chain which is coded in the RNA. Various types of RNA participate in protein synthesis in different ways. Messenger RNA serves as a matrix in protein synthesis so in another way it is called a matrix RNA (mRNA). Ribosomal RNA together with proteins forms ribosomes. Transfer RNA (tRNA) delivers amino acids to the ribosomes where protein synthesis is performed. The animation is operated by the "Start"/"Stop" and the "Reset" buttons. A group of switches is applied to choose a way to vary a scale. If you choose "manually" then another group of switches appears to let you to choose a scale of an image.