Transcription & Translation

How RNA Becomes a Protein

Transcription

• This is the process from which mRNA makes a copy of the DNA base sequence

• *REMEMBER* URACIL (U) pairs with A, not T.

• Ex. DNA: AATCGGATTmRNA: UUAGCCUAA

• A group of 3 nitrogenous bases (A, U, C, G in RNA) code for one amino acid.

• Each group of 3 bases is called a codon• Ex. The codon UUU results in the amino acid

phenylalanine being placed in a protein

Example

• Use your codon table provided to determine which amino acid is being coded for:

• CCA • AGU • GGA

Translation

• The process by which the tRNA matches the appropriate amino acid to the mRNA

• *NOTE* the amino acid is determined by the mRNA NOT the tRNA

DNA Process mRNA Codon Process tRNA Anticodon

Amino Acid

TTT Transcription AAA Translation UUU Lysine

ACG Transcription UGC Translation ACG Cysteine

Start Codon

• AUG Methionine• Tells the RNA where to begin copying from the

DNA• This is called the “start codon”

Stop Codon

• UAA Stop• UAG Stop• UGA Stop• Tells the RNA where to stop copying from the

DNA• Called the “stop codon”

Example• In the sequence of DNA, determine the mRNA

codon, find the start sequence, the stop sequence and determine the proteins involved.

• *Once you find the start and stop codon on your mRNA strand, circle it*

• DNA: C A T A C A A A T C T A T T G C• mRNA:• Amino Acids: