Topic 3 - Genetic Variants And Their Effects Flashcards
What are genetic variants?
Small changes in the order of bases that make up a strand of DNA
What is the difference between genotype and phenotype?
Genotype refers to the genes present in the DNA, while phenotype refers to the visible effects of those genes
What happens to coding DNA when a genetic variant occurs?
It alters the sequence of bases, changing the sequence of amino acids and thus the final structure of the protein
What is the role of RNA polymerase in relation to non-coding DNA?
RNA polymerase binds to non-coding DNA, and changes in this DNA can affect the amount of RNA polymerase that binds
How does a genetic variant in non-coding DNA affect mRNA production?
If less RNA polymerase can bind, less mRNA is formed, affecting the structure of the final protein
What are the three types of mutations that can occur in DNA?
- Insertion 2. Deletion 3. Substitution
What is the effect of insertion mutations?
Changes the way the DNA sequence is read, potentially altering all amino acids coded for after the insertion
What is the effect of deletion mutations?
Changes the way the DNA sequence is read, potentially altering all amino acids coded for after the deletion
What happens during substitution mutations?
It may change one amino acid in the sequence or may not change the amino acid at all
How does a change in the type/sequence of amino acids affect proteins?
It affects the way the protein folds and therefore its structure
Do most mutations alter the protein significantly?
Most mutations do not alter the protein or only do so slightly
What can be a serious effect of mutations on proteins?
The substrate may not fit into the active site, preventing the protein from functioning
What can happen to structural proteins due to mutations?
They may lose their shape
Can mutations occur in the non-coding parts of DNA?
Yes, they can affect whether the genes are expressed
Fill in the blank: A genetic variant will alter the sequence of bases (e.g ACT > AGT) and therefore will change the sequence of _______.
amino acids
