3.9B and 3.10B **Biology and Higher Only** - Genetic Variants and their Effects Flashcards
What are genetic variants?
Genetic variants are small changes in the order of bases that make up a strand of DNA.
How do genetic variants affect proteins?
They can affect the structure of proteins in different ways, depending on whether they occur in coding DNA or non-coding DNA.
What is the difference between genotype and phenotype?
Genotype refers to the genes present in the DNA of an individual, whereas phenotype refers to the visible effects of those genes.
What happens when a genetic variant occurs in coding DNA?
A genetic variant will alter the sequence of bases and therefore will change the sequence of amino acids, altering the final structure of the protein produced.
How does a genetic variant in non-coding DNA affect phenotype?
A change in the order of bases in non-coding DNA can affect the amount of RNA polymerase that can bind to it, influencing mRNA formation and the structure of the final protein.
What are the types of mutations?
- Insertion: A base is inserted into the code.
- Deletion: A base is deleted from the code.
- Substitution: A base is substituted.
What is the effect of an insertion mutation?
It changes the way the code is read, potentially altering all amino acids coded for after the insertion.
What is the effect of a deletion mutation?
It changes the way the code is read, potentially altering all amino acids coded for after the deletion.
What is the effect of a substitution mutation?
It will only change one amino acid in the sequence or may not change the amino acid at all.
How do mutations affect protein structure?
A change in the type/sequence of amino acids will affect the way it folds and therefore the structure.
What is the general impact of most mutations?
Most mutations do not alter the protein or only do so slightly.
What can serious mutations cause?
They can change the shape of a protein, preventing substrates from fitting into the active site or causing structural proteins to lose their shape.
Can mutations occur in non-coding DNA?
Yes, there can be mutations in the non-coding parts of DNA that control whether the genes are expressed.
