Understanding DNA Mutations: Point and Frame Shift Changes Explained
This informative piece explores the two main types of mutations in DNA: point mutations and frame shift mutations. Point mutations involve the substitution of a single nucleotide, which may be silent or lead to an amino acid change. Frame shift mutations, caused by nucleotide insertions or deletions, shift the entire DNA/RNA sequence and can significantly alter proteins. The piece also addresses the impact of somatic and germ cell mutations on future generations and highlights mutagens, environmental agents that harm DNA.
Understanding DNA Mutations: Point and Frame Shift Changes Explained
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Presentation Transcript
Defined: one nucleotide is substituted for another Often repaired by spellchecker enzyme May lead to amino acid change See animation May not lead to any change (Silent Mutation) Ex: DNA “CCC” is mutated into “CCG” Same amino acid is created (glycine) Gene: Point Mutations T A C A G T G G T C A A A DNA U G U C A C A C A G U U U mRNA cysteine glutamine histidine glutamine phenylalanine Amino acids
Gene: Frame Shift Mutation C A C A G T G G T C A A A DNA • Defined: insertion/deletion of a nucleotide • Entire sequence of DNA/RNA after the mutation is shifted (see animation) • Much more serious to the final protein G U G U C A C C A G U U U mRNA cysteine histidine glutamine phenylalanine Amino acids histidine serine leucine
Gene: Frame Shift Mutation C A C A G T G G T C A A A DNA U G U C A C C A G U U U G mRNA histidine glutamine phenylalanine cysteine Amino acids glutamine proline valine
Impact on Offspring • Somatic cell mutations • Affect only the individual • Not passed on to future generations • Ex: Muscle cell mutation • Germ cell mutations • Germ cells create egg and sperm by meiosis • May be passed to future generations
Mutation Causes • Mutagen: agents in the environment that can change DNA • Speed up replication process • Break apart nucleotides • Ex: UV sunlight breaks hydrogen bond between thymine (T) and adenine (A)
Kobe Kuiz • How are proteins affected if the DNA code is mutated? Example: ATTCGAGG is mutated to ATTCGTGG • What is the difference between a point mutation and frame shift mutations? • When are mutations passed on to future generations? • What is a mutagen and how do they cause problems?
