How does a mutation in the gene for a protein affect the protein?

What gene mutation is this?

• leu thr ala asn. The gene has a mutation and is changed to the sequence below GAC GGA CGA TTA What kind of mutation is this? What is the new mRNA strand produced by this mutated gene? Does the mutation affect the protein produced? (explain) (Yes i know it's cheating, yes i know i should do my own homework, i did the other 70something problems on my own but i'm stuck on this one and would appreciate help, thankyou)

• Answer:

  The DNA gets copied into mRNA. Remember that G pairs with C and A pairs with U so the mRNA sequence for above can be copied like so:- DNA GAC GGA CGA TTA mRNA CUG CCU GCU AAU If you google images for genetic code, you can read the mRNA sequence to find the amino acids. For example CUG is Leu. The whole thing is:- Leu Pro Ala Asn As you can see, one amino acid has changed from the original leu thr ala asn. Compare the pro to the thr sequences to find out what has changed. It looks like the original A for thr has changed to a C to make it pro. This is a "simple base substitution" or "point mutation". So to answer your questions What kind of mutation - "simple base substitution" or "point mutation". New mRNA strand - CUG CCU GCU AAU Does the mutation affect the protein. - yes because one amino acid is different