What would happen if there was a substitution of one base for another in one of Mrna codon?

What would happen if there was a substitution of one base for another in one of Mrna codon?

Although a base substitution alters only a single codon in a gene, it can still have a significant impact on protein production. In fact, depending on the nature of the codon change, base substitutions can lead to three different subcategories of mutations.

What happens when a codon is substituted?

A substitution is a mutation that exchanges one base for another (i.e., a change in a single “chemical letter” such as switching an A to a G). Such a substitution could: change a codon to one that encodes a different amino acid and cause a small change in the protein produced.

What happens to the amino acid sequence if there is a base substitution in the third position of the second codon?

Silent: If abase substitution occurs in the third position of the codon there is a good chance that a synonymous codon will be generated. Thus the amino acid sequence encoded by the gene is not changed and the mutation is said to be silent.

What are the effects of substitution mutation?

A substitution mutation can cause the following: Change in the coding of amino acids codon to a particular stop codon resulting in an incomplete protein, which is usually non-functional. Can cause Silent mutations where a codon change can encode the same amino acid resulting in no changes in the protein synthesized.

What happens when a stop codon is reached prematurely?

Thus, nonsense mutations occur when a premature nonsense or stop codon is introduced in the DNA sequence. When the mutated sequence is translated into a protein, the resulting protein is incomplete and shorter than normal. Consequently, most nonsense mutations result in nonfunctional proteins.

What happens in substitution mutation?

A substitution is a mutation that exchanges one base for another (i.e., a change in a single “chemical letter” such as switching an A to a G). Such a substitution could: change a codon to one that encodes a different amino acid and cause a small change in the protein produced.

Which is a stop codon instead of an amino acid?

The new codon specifies a STOP codon instead of an amino acid, so translation will be terminated early resulting in a shortened protein. The codon UAU encodes tyrosine. A mutation changes the codon to UAA, which specifies a stop codon rather than an amino acid.

How does a mutation affect the codon sequence?

One type of base is substituted for a different base, so it does alter the codon sequence. However, the new codon still encodes the same amino acid, so the mutation is silent because it does not alter amino acid sequence. What is a missense mutation- does the mutation alter the codon sequence?

Can a base substitution be a silent mutation?

First, the base substitution can be a silent mutation where the altered codon corresponds to the same amino acid. Second, the base substitution can be a missense mutation where the altered codon corresponds to a different amino acid. Or third, the base substitution can be a nonsense mutation where the altered codon corresponds to a stop signal.

How does a mutation change the codon UAU?

The new codon specifies a STOP codon instead of an amino acid, so translation will be terminated early resulting in a shortened protein. The codon UAU encodes tyrosine. A mutation changes the codon to UAA, which specifies a stop codon rather than an amino acid. What type of mutation has occurred? Nonsense mutation