Fundamentals 3 Flashcards
(20 cards)
What are the 4 classes of chromosomal structural change ?
- Deletion
- Duplication
- Inversion
- Translocation
What is deletion ?
The loss of part of all of a chromosome
What is duplication ?
Doubling of part or all of a chromosome
What is inversion ?
Break and repair that results in flipping around part of a chromosome
What is translocation ?
Putting a piece of a chromosome somewhere it is not normally found
What is transposon mobilisation ?
The process by which transposons move from one location to another within the genome.
What is a tranposon ?
Transposable elements which are pieces of DNA that jump around the genome, resulting in repetitive sequences
What can cause deletions ?
- Transposon mobilisation
- Incorrect repair of DNA double strand breaks
How are DNA double strand breaks repaired ?
- Homologous recombination- accurate
- Non-homologous end joining- error prone
What is monosomy ?
Where an individual is missing one chromosome from a pair of homologous chromosomes
Describe the structure of a chromosome
A chromosome has a p (petite) and q arm, which are divided by regions. These regions are divided by bands, and the bands are divided into sub-bands.
What are copy number variations (CNVs) ?
Where large segments of DNA are duplicated
What is paracentric inversion ?
The inversion does not include the centromere
What is pericentric inversion ?
The inversion includes the centromere
What is the Philadelphia chromosome?
A portion of the ABL1 gene on chromosome 9 is transferred to chromosome 22.
It fuses with the BCR gene on chromosome 22.
It causes cancer.
What is a silent mutation ?
There is a change in a single DNA base pair, forming a different codon, but the SAME amino acid is produced
What is a missense mutation ?
There is a change in a base pair that leads to a DIFFERENT amino acid being produced
What is a nonsense mutation ?
A change in a single base pair changes a codon for an amino acids into a STOP codon.
Results in truncation of the protein.
What are point mutations ?
A change in a single nucleotide base in the DNA sequence
What is disjunction ?
The pulling apart of chromosomes in cell division
