USTET Science Practice Test 2025 - Free Science Practice Questions and Study Guide

Transcription is the process through which a complementary RNA sequence is synthesized from a DNA template. During transcription, the enzyme RNA polymerase binds to a specific region of the DNA strand, known as the promoter, and unwinds the DNA helix. It then reads the nucleotide sequence of the DNA and synthesizes a single-stranded RNA molecule by pairing the DNA bases with their complementary RNA bases. For instance, if the DNA template has an adenine (A), the RNA will have a uracil (U) instead of thymine (T), pairing it with cytosine (C), guanine (G), or thymine (T) appropriately. This process is crucial for gene expression, as it produces messenger RNA (mRNA) which carries the genetic information needed for protein synthesis.

Other processes such as replication involve copying the entire DNA molecule to ensure accurate duplication prior to cell division, mutation refers to changes in the DNA sequence which may affect function, and translation is the process by which the RNA sequence is used to synthesize proteins. Each of these processes has its distinct role in genetics and cellular function, but only transcription specifically creates RNA from a DNA template.