DNA is transcribed to messenger RNA (mRNA), and the mRNA is translated to proteins on the ribosomes. A sequence of three nucleotides on an mRNA molecule is called a codon. As you can see in the table, most codons specify a particular amino acid to be added to the growing protein chain. In addition, one codon (shown in blue) codes for the amino acid methionine and functions as a “start” signal. Three codons (shown in red) do not code for amino acids, but instead function as “stop” signals.
| U | C | A | G | ||||||
| U | UUU | Phe | UCU | Ser | UAU | Tyr | UGU | Cys | U |
| UUC | UCC | UAC | UGC | C | |||||
| UUA | Leu | UCA | UAA Stop | UGA Stop | A | ||||
| UUG | UCG | UAG Stop | UGG | Trp | G | ||||
| C | CUU | Leu | CCU | Pro | CAU | His | CGU | Arg | U |
| CUC | CCC | CAC | CGC | C | |||||
| CUA | CCA | CAA | Gln | CGA | A | ||||
| CUG | CCG | CAG | CGG | G | |||||
| A | AUU | Ile | ACU | Thr | AAU | Asn | AGU | Ser | U |
| AUC | ACC | AAC | AGC | C | |||||
| AUA | ACA | AAA | Lys | AGA | Arg | A | |||
| AUG | Met or start |
ACG | AAG | AGG | G | ||||
| G | GUU | Val | GCU | Ala | GAU | Asp | GGU | Gly | U |
| GUC | GCC | GAC | GGC | C | |||||
| GUA | GCA | GAA | Glu | GGA | A | ||||
| GUG | GCG | GAG | GGG | G | |||||
Part A - Understanding the genetic code
Use the table to sort the following ten codons into one of the three bins, according to whether they code for a start codon, an in-sequence amino acid, or a stop codon.
Drag each item to the appropriate bin.
View Available Hint(s)for Part A
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