DNA: Mutations Lesson
The DNA Code
By this point, you may be asking yourself
“What’s the point of all this? How do these nitrogen bases relate to me? ”
This is when you will learn how to “decipher the DNA code.”
After you learn the secret message, you will then learn what can happen when there is a mistake.
Sequence
Scientists now know which mRNA codons match each amino acid. This means that if you know the sequence of DNA or mRNA, you can figure out the sequence of amino acids that make a protein.
There are 20 kinds of amino acids, each of which is coded for by a three-nucleotide mRNA codon (such as CCG or UAG). With four letters, A, U, C, & G, a possible 64 mRNA codons can be formed; so most amino acids can have several codons (such as AAA, AAC, AAU and AAG).
The image below is a mRNA table and a mRNA codon wheel for determining which mRNA codons will code for each amino acid.
Don’t worry. You do not have to memorize these two charts. You should, though, be able to use it to decode the amino acid for a particular codon.
Watch the video below to learn all about mutations.
Types of Mutations
Watch the presentation below to learn more:
Mutations Challenge and Before You Go
Practice Time! Use the knowledge you learned from the lesson to complete the practice activities below.
Answer Key Links to an external site.
Before You Go - You Need To Know
The following key points are from the explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.
- What is a codon?
- Three nitrogen bases that code for an amino acid.
- What is a mutation?
- A mutation is a random change in the DNA sequence.
- What are 2 causes of a mutation?
- An error in DNA replication, transcription, or translation.
- Mutagen: Anything that causes a mutation, such as environmental factors.
IMAGES CREATED BY GAVS (SHUTTERSTOCK)