Mutation Types and Effects

Dr. Leblanc introduces unit 7 on mutagenesis and repair, focusing on DNA sequencing errors. The lecture covers the types of mutations, including point mutations, transitions, transversions, and frameshift mutations, and their effects on coding and non-coding regions. It also discusses suppressor mutations and their role in genetic repair. The lecture emphasizes the evolutionary significance of mutations, despite their often deleterious nature, and the various repair mechanisms that have evolved.

What is the primary role of mutations in evolutionary biology?

• They eliminate harmful traits.

• They always cause diseases.

• They prevent genetic diversity.

• They provide allelic variations.

Which term describes a mutation that changes a mutant allele back to the wild type?

• Reverse mutation

• Point mutation

• Forward mutation

• Silent mutation

What type of mutation results in a change in a single base pair?

• Frame shift mutation

• Point mutation

• Insertion mutation

• Nonsense mutation

In sickle cell anemia, what is the result of the single base pair substitution?

• Formation of normal red blood cells

• Increased oxygen levels in blood

• Production of a non-functional protein

• Crystallization of hemoglobin molecules

What is a silent mutation?

• A mutation that deletes a nucleotide

• A mutation that introduces a stop codon

• A mutation that does not change the amino acid sequence

• A mutation that changes the amino acid sequence

What happens in a frame shift mutation?

• The reading frame of the gene is altered

• A stop codon is introduced

• The gene is duplicated

• A single nucleotide is changed

How does a frame shift mutation affect protein synthesis?

• It results in a longer protein

• It causes premature stop codons

• It has no effect on the protein

• It only affects the first amino acid

What is the effect of a mutation in the promoter region of a gene?

• It has no effect on transcription

• It can either increase or decrease transcription

• It always increases transcription

• It stops transcription completely

What are suppressor mutations?

• Mutations that mitigate the effect of the first mutation

• Mutations that occur only in non-coding regions

• Mutations that have no effect on the first mutation

• Mutations that enhance the effect of the first mutation

What is the difference between intragenic and intergenic suppressors?

• Both occur in different genes

• Both occur in the same gene

• Intragenic suppressors occur in the same gene, intergenic in different genes

• Intragenic suppressors occur in different genes, intergenic in the same gene