Bacterial Genetics Flashcards
What is natural selection?
A method of evolution
What is spontaneous mutation?
Base substitution (point mutation)
What is missense mutation?
Changes the base; ALWAYS changes the protein
What is nonsense mutation?
Stops the protein early where it’s not supposed to stop; Changes the DNA and RNA to an early STOP codon
What is a silent mutation?
Change the DNA and RNA but the amino acid stays the same
Which mutation adds/deletes nucleotides?
Frame shift mutation
What are the radiation mutations?
UV light and ionizing
What does UV light cause?
Thymine diner forming that distorts the DNA
Although UV light doesn’t cause mutation what does it do?
When the body goes to repair it, it mispairs with the wrong bases
What does ionizing do?
Causes the DNA to break in spots and causes it to mutate
What new traits can genetic change add?
Mutations and gene transfer
Are bacteria static or dynamic in the genes they can express during their lifespan?
Dynamic— 1) gene regulation
2) mutation
3) gene transfers
What is base incorporation?
Where one wrong base is put into place
How do you repair a base incorporation mutation
DNA polymerase proofreads & mismatch repair
Name what happens in the steps for base incorporation repair
1) an enzyme cuts the strand with the wrong base & takes it out
2) DNA polymerase synthesizes a new strand & puts it in
Name the repairs of thymine dimers
Light repair
Excision or dark repair
SOS repair
What is SOS repair
It’s the emergency repair. It kicks in when you have lots of thymine dimers where the other systems are overwhelmed.
They try to replicate across the thymine dimers & repair but they can’t proofread
What is genetic recombination
When you get DNA from 2 sources combing together in an organism & the product is called recombinants
What can bacteria transfer
Chromosome segments: narrow host range
Plasmids
If transfers occur, what does it need to be passed on to progeny
Origin of replication
What is homologous recombination
Finds a similar area in the chromosome & it physically kicks out the original base & base pairs with the other strand; may give the cell new characteristics
HAVE to be similar species to do homologous recombination
Can plasmids self replicate
Yes. & they can jump from one species to another
Name the methods of transfer
Transformation
Transduction
Conjugation
Describe Transformation
Transfer “NAKED” DNA to competent cells
Only 1 strand enters so not every cell is competent to begin with. Only 1 strand of DNA enters & other breaks down
Homologous recombination
Where does the naked DNA come from
It’s dead bacteria floating in the environment from dead bacteria
What is Transduction
BACTERIOPHAGES accidentally pick up bacterial DNA during replication & assembly
Transfer bacterial genes to new cells
Homologous recombination
What is conjugation
BACTERIAL SEX
