DNA transcription and Translation

Transcription

DNA ➡️ mRNA

Where it happens (Transcription)

In the nucleus

Goal of Transcription

Copy the instructions from DNA to make mRNA (messenger RNA)

Initiation (Transcription)

RNA polymerase binds to the promoter region on the DNA.

Unwinding (Transcription)

DNA strands separate to expose the template strand.

Elongation (Transcription)

RNA polymerase adds RNA bases (A, U, C, G) that are complementary to the DNA.

Termination (Transcription)

When it hits a terminator sequence, RNA polymerase stops.

mRNA is released

It's now ready for translation!

Translation

mRNA ➡️ Protein

Where it happens (Translation)

In the cytoplasm (at a ribosome)

Goal of Translation

Read the mRNA and build a protein

Initiation (Translation)

mRNA binds to the ribosome. A tRNA with the matching anticodon brings the start amino acid (usually methionine).

Elongation (Translation)

tRNA brings amino acids to the ribosome by matching its bases to mRNA. The ribosome joins the amino acids into a chain.

Termination (Translation)

A stop codon tells the ribosome to stop. The new protein is released.

RNA base replacement

In RNA, U (uracil) replaces T (thymine)!