Background: DNA represents the architectural blueprint for all living systems, encoding specific instructions in the sequence of its four nitrogen-containing base pairs that are necessary for building the organism.

During the process of transcription, the information in the DNA codons of a gene is transcribed into RNA.

A change in the DNA sequence, for example as a result of a "mistake" during DNA replication, is defined as a mutation. Mutations may result in a change in the "blueprint," which may then change the resulting protein product.

Assignment details for part one:

Transcribe and translate EACH of the three following DNA gene sequences. Turn these in using the graphic organizer. The letters represent the DNA N-base sequences of the genes.

The first is the original gene. The next two are mutations of the original. Note that the changes (mutations) are shown in red.

Original Gene sequence 3'-T A C C C T T T A G T A G C C A C T-5

Mutated gene sequence 1 3'-T A C G C T T T A G T A G C C A T T-5'

Mutated gene sequence 2 3'-T A A C C T T T A C T A G G C A C T-5'

Also, answer the following questions:

• What is the significance of the first and last codons of an mRNA transcript?
• What meaning do these mRNA codons have for protein synthesis?
• Did the mutations result in a change in the final proteins? If so, describe the change.
• In general, why might a change in amino acid sequence affect protein function?