AP BIOLOGY

Detailed explanation-1: -Upon recruitment of RNA polymerase III, the SUP4 tRNA gene promoter opens in two segments, one surrounding the transcription start site and the other located ∼7 bp upstream (Kassavetis et al. 1992).

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: -Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins). RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule. Transcription ends in a process called termination.

Detailed explanation-4: -RNA polymerase synthesizes an RNA transcript complementary to the DNA template strand in the 5’ to 3’ direction. It moves forward along the template strand in the 3’ to 5’ direction, opening the DNA double helix as it goes.