CB10: Molecular genetics & disease Flashcards
Define mutagenesis.
The process by which mutations occur.
Define mutation.
A change in the genetic code/genome.
What are the 3 main types of mutations?
- Point mutations
- Deletions
- Insertions
What are point mutations caused by?
DNA Polymerase & some chemicals
What are deletions caused by?
Radiation, transposons & some chemicals
What are insertions caused by?
Radiation, transposons & some chemicals
How does DNA Polymerase cause mutations?
DNA Polymerase can make errors so there is a base mismatch leading to a transversion or transition.
What type of mutation does spontaneous depurination/decay cause?
Transversion or transition
What type of mutation does radiation cause?
Insertions & deletions
What type of mutation do chemicals cause?
Point mutations, insertions & deletions
What type of mutation does oxidative damage cause?
Transversion
What type of mutation do transposons cause?
Insertions or deletions
What are transposons?
A type of gene that can move autonomously across the genome.
How do mutations cause cancer?
Accumulation of mutations & mutations in DNA repair modify the cell cycle leading to tumour growth.
How does a mutation in the telomerase gene lead to tumour growth?
It makes the cell immortal
What mutation makes the cell immortal?
A mutation in the telomerase gene.
How does chloramphenicol work against bacteria?
It inhibits the enzyme peptyl transferodase in prokaryotes. The charged tRNA molecule then seems unable to bind to the A site of the ribosome.
How does streptomyocin work against bacteria?
It causes misreading that interferes with the binding of the codon & anticodon during translation.
How does puromycin work against bacteria?
It causes premature chain termination during translation.
How does tetracycline work against bacteria?
It prevents the tRNA from binding to the A site of the ribosome.
How does penicillin work?
It inhibits the enzyme involved in the catalysis of bacterial cell wall formation. Without a cell wall, the bacterium fills with water and the cell lyses.
How do plasmids contribute to antibiotic resistance?
They replicate independently and can be transferred from bacteria to bacteria. They can have multiple resistance gene.
