What Is A Mutation printable pdf download

Name: _______________________________

Date: ________________________________

What is a mutation?

A mutation is a permanent, heritable change in the DNA sequence of a gene. When a mutation occurs, one

or several bases can be added, deleted, or replaced. Mutations in a gene's DNA sequence can alter the

amino acid sequence of the protein encoded by the gene.

How does this happen? Like words in a sentence, the DNA sequence of each gene determines the amino

acid sequence for the protein it encodes. This sequence is read, or "translated," in groups of three

nucleotide bases, with each three-letter "word," or codon, specifying a single amino acid in a protein.

What causes mutations? Mutations often happen when mistakes occur during replication. Many mutations

are caused by mutagens like UV light, radiation, and certain chemical toxins.

How often do mutations happen? Mutations are rare events. The average rate of mutations is one in a

million replications.

Are you a mutant? Since DNA replication takes place in your body so many times during your lifetime, at

least one of your cells contains a mutation.

Activity 1. Mutate a sentence!

We can think about DNA gene sequence as a sentence made up entirely of three-letter words. In the DNA

sequence, each three-letter word is a "codon," specifying a single amino acid in a protein. Have a look at

this sentence:

Thesunwashotbuttheoldmandidnotgethishat

If you were to split this sentence into individual three-letter words, you would probably read it like this:

The sun was hot but the old man did not get his hat.

This sentence represents a gene. Each letter corresponds to a nucleotide base, and each word represents a

codon. Only one of the three possible "reading frames" translates into an understandable sentence. In the

same way, only one three-letter "reading frame" within a gene codes for the correct protein. Now, go back

to the original sentence.

The sun was hot but the old man did not get his hat.

What if you shifted the three-letter "reading frame?" In the space below, show how you can change the

"reading frame" of the above sentence by inserting or deleting letters within the sentence. The result should

be a “nonsense” sentence.

In the space below, make a mutation that maintains or changes the meaning of the sentence without

creating such nonsense.

What Is A Mutation