Mutations Flashcards
Chapter 3 Lesson 5 (21 cards)
What is a mutation?
A change in the DNA sequence.
Are mutations good or bad?
It can be good, bad, or neutral.
Mutations can introduce genetic diversity, which helps evolution.
But they can also cause diseases if they interfere with important proteins.
What is a point mutation?
Affects one or a few bases in the DNA. Small-scale.
What is a Chromosomal Mutation?
Affects large chunks of DNA or whole chromosome structure. Big changes.
What is a substitution?
One base is replaced by another.
What is an insertion?
One or more bases are added to the DNA.
What is a deletion (point mutation)?
One or more bases are removed.
What is a frameshift mutation?
A shift in the reading frame due to insertion or deletion.
Changes every codon after the mutation → totally different amino acids → wrong protein.
What are the types of point mutation?
Substitution, Insertion, Deletion & Frameshift
What is a missense mutation?
One base change causes one amino acid to change.
What is a nonsense mutation?
One base change turns an amino acid codon into a stop codon → protein is cut short.
What is a silent mutation?
A base changes, but the amino acid stays the same.
This happens because the genetic code is redundant (e.g., GAA and GAG both code for Glutamic acid).
What are the 4 Chromosomal Mutations?
chromosomal deletion, chromosomal duplication, chromosomal inversion ,translocation
What is chromosomal deletion?
A piece of chromosome is lost.
What is chromosomal duplication?
A section is copied and added again.
What is chromosomal inversion?
A section is flipped and reinserted.
What is translocation?
A piece breaks off and attaches to another chromosome.
How do Spontaneous Mutations Happen?
Mistakes during DNA replication.
DNA copying machinery isn’t perfect.
How are Mutations Induced?
Induced means caused by outside factors. (mutagens)
What are Mutagenic Agents?
UV radiation, chemicals, metals (arsenic, chromium, nickel), radioactive decay.
Some examples of Mutation Impacts on Humans
Cystic Fibrosis – mutation causes thick mucus in lungs.
Sickle Cell Anemia – point mutation changes shape of red blood cells.
Cancer – mutations in genes that control cell growth.
