AP BIOLOGY

Detailed explanation-1: -Transcription is carried out by an enzyme called RNA polymerase and a number of accessory proteins called transcription factors. Transcription factors can bind to specific DNA sequences called enhancer and promoter sequences in order to recruit RNA polymerase to an appropriate transcription site.

Detailed explanation-2: -RNA polymerase III transcribes the genes for tRNAs and for the smallest species of ribosomal RNA (5S rRNA). Some of the small RNAs involved in splicing and protein transport (snRNAs and scRNAs) are also transcribed by RNA polymerase III, while others are polymerase II transcripts.

Detailed explanation-3: -RNA polymerase (RNAP) is the essential enzyme responsible for transcribing the genetic information stored in DNA to RNA.

Detailed explanation-4: -The enzymes that perform transcription are called RNA polymerases. Like the DNA polymerase that catalyzes DNA replication (discussed in Chapter 5), RNA polymerases catalyze the formation of the phosphodiester bonds that link the nucleotides together to form a linear chain.

Detailed explanation-5: -RNA polymerase is used in transcription. This is the first step in gene expression in which a single strand of double-stranded DNA is used as a template to synthesize a complementary single-stranded RNA. RNA polymerase is responsible for synthesizing mRNA, and rRNA, which are used in translation.