AP BIOLOGY

Detailed explanation-1: -DNA is double-stranded, but only one strand serves as a template for transcription at any given time. This template strand is called the noncoding strand. The nontemplate strand is referred to as the coding strand because its sequence will be the same as that of the new RNA molecule.

Detailed explanation-2: -Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). DNA safely and stably stores genetic material in the nuclei of cells as a reference, or template.

Detailed explanation-3: -The goal of transcription is to make a RNA copy of a gene’s DNA sequence. For a protein-coding gene, the RNA copy, or transcript, carries the information needed to build a polypeptide (protein or protein subunit).

Detailed explanation-4: -The template strand is the one that RNA polymerase uses as the basis to build the RNA. This strand is also called the non-coding strand or the antisense strand. The non-template strand has the identical sequence of the RNA (except for the substituion of U for T).

Detailed explanation-5: -The RNA pol “walks” along the DNA molecule reading each base, finding the complementary RNA nucleotide, and adding it to the growing RNA strand. The RNA is ALWAYS built in the 5’ to 3’ direction, so it ALWAYS reads the template strand in the 3’ to 5’ direction.