RNA polymerase is the enzyme that synthesizes RNA from a DNA template during transcription. It binds promoter sequences (often alongside transcription factors) to start reading DNA and building a complementary RNA strand, the first step in turning genes into proteins.
RNA polymerase is the enzyme that does transcription. It reads a strand of DNA (the template strand) and builds a matching RNA molecule, base by base. This is step one of the central dogma, the flow of genetic information from DNA to RNA to protein (EK 6.3.A.2).
Before it can start, RNA polymerase has to land in the right spot. It binds to a DNA sequence called the promoter, often with help from transcription factors (EK 6.6.A.1). Those promoter and enhancer sequences can sit upstream or downstream of where transcription actually begins. Once RNA polymerase is locked in, it moves along the DNA and synthesizes RNA. That RNA can be mRNA (which carries instructions to the ribosome), tRNA, or rRNA, depending on the gene.
RNA polymerase is the engine behind gene expression, which lives mostly in Unit 6: Gene Expression and Regulation. It directly supports AP Bio 6.3.A (how information flows from DNA to RNA to protein) and AP Bio 6.6.A (how transcription factors binding promoter regions affects gene expression). Here's the big idea: cells don't change their DNA to become different cell types, they change which genes get transcribed. Control where and when RNA polymerase fires, and you control the cell's phenotype (EK 6.6.B.1). That connects straight to the course theme of how organisms transmit and express genetic information.
Keep studying AP Biology Unit 6
Transcription Factors and Promoters (Unit 6)
RNA polymerase rarely works alone. Transcription factors bind promoter and enhancer sequences to recruit or block the polymerase, so they're the on/off switches and RNA polymerase is the machine they control.
Signal Transduction (Unit 4)
A signaling cascade that ends in the nucleus often works by activating transcription factors. Those factors then change whether RNA polymerase transcribes a gene, which is how an outside signal ends up altering protein production inside the cell.
Translation and the Ribosome (Unit 6)
RNA polymerase makes the mRNA; the ribosome reads it. In prokaryotes the two overlap, so a ribosome can start translating an mRNA while RNA polymerase is still transcribing it (EK 6.4.A.2).
Reverse Transcription in HIV (Unit 6)
HIV runs the central dogma backward to insert its genome into your DNA, but once it's integrated, your own RNA polymerase transcribes the viral genes. The virus hijacks your transcription machinery to make new viral proteins.
Expect RNA polymerase in questions about where transcription starts and what happens when you block it. One classic stem describes a compound that stops RNA polymerase from moving past the promoter in a prokaryote, then asks how that changes translation. Since prokaryotic translation happens on the mRNA as it's being made, blocking the polymerase shuts down both transcription and the translation riding along with it. You'll also see RNA polymerase in HIV questions: after viral RNA is reverse transcribed and integrated, the host cell's own machinery (including RNA polymerase) transcribes the viral genes. You won't usually calculate anything here. The skill is explaining cause and effect: if you change the polymerase or its access to the promoter, what happens downstream to RNA and protein?
Both are enzymes that build a nucleic acid off a DNA template, but they do different jobs. DNA polymerase copies DNA into DNA during replication. RNA polymerase copies DNA into RNA during transcription, and unlike DNA polymerase, it doesn't need a primer to start.
RNA polymerase synthesizes RNA from a DNA template strand during transcription, the first step of the central dogma.
It binds promoter sequences, often together with transcription factors, to start transcription (EK 6.6.A.1).
Controlling when and where RNA polymerase transcribes a gene is how cells produce different proteins and become different cell types (EK 6.6.B.1).
In prokaryotes, transcription and translation happen at the same time, so blocking RNA polymerase also stops the translation occurring on that mRNA (EK 6.4.A.2).
HIV integrates into your genome, then relies on your own RNA polymerase to transcribe its genes into new viral RNA.
RNA polymerase makes RNA; DNA polymerase makes DNA. Don't mix them up.
It builds an RNA strand from a DNA template during transcription. After binding a promoter (sometimes with transcription factors), it reads the template strand and synthesizes complementary RNA, which is the first step in making a protein.
No. RNA polymerase makes RNA from a DNA template during transcription, while DNA polymerase copies DNA into more DNA during replication. RNA polymerase also doesn't need a primer to get started, but DNA polymerase does.
Transcription factors and negative regulatory molecules control whether RNA polymerase can bind the promoter and transcribe a gene (EK 6.6.A.1 and 6.6.A.2). By turning that access on or off, cells decide which genes get expressed, which shapes the cell's phenotype.
In prokaryotes, ribosomes start translating an mRNA while it's still being transcribed (EK 6.4.A.2). If you stop RNA polymerase at the promoter, no mRNA is made, so there's nothing for the ribosome to translate.
Once HIV is reverse transcribed and integrated into the host genome, the host cell's RNA polymerase transcribes the viral genes. The virus relies on your machinery to produce new viral RNA and proteins.