Flashcards in Lecture 11 Deck (62):
Define genetic recombination
Incorporation of new DNA into an organism, but not by sexual reproduction
In transformation, does the donor die?
Yes, the donor dies and breaks apart, as does it's DNA
What is incorporation of new DNA into an organism through a method that is not sexual reproduction called?
What happens during transformation?
A donor breaks apart, as does it's chromosomes, and gets its DNA incorporated into another bacteria, called the recipient
What are the two bacteria involved in transformation normally called?
The donor and the recipient
What does the donor do in transformation?
Have itself and its DNA break apart
What does the recipient do in transformation?
Incorporate the donor's genetic material into its genome
Transfer of genetic material between two bacterial cells through a pilus
What is the sex pilus?
A tube formed by an F+ bacterial cell that connects two bacterial cells together
What are the mating types in conjugation?
It is based on the fertility factor, F+ and F-
How many mating types are there in conjugation?
Two, F+ and F-
Is an F+ cell capable of producing a sex pilus?
Yes, because it has the F factor
Is an F- cell capable of making a sex pilus?
No, because it doesn't have the F factor
Is the F factor part of a bacteria's DNA?
No, it is a plasmid
What is a mathod of gene exchange between bacterial cells that is most anaologus to sexual reproduction?
Conjugation, because of the inclusion of a sex pilus
Does conjugation have male and female mating types?
No, they have F+ and F- mating types
How is an F+ cell different from an F- cell?
1. Has an F factor
2. Can produce a sex pilus
3. Is more negative that an F- cell
How is an F- cell different from an F+ cell?
1. It does not have the F factor
2. Cannot produce a sex pilus
3. it is more positive than an F+ cell
How to F+ cells find F- cells?
An F+ cell is more negative than and F- cell and is attracted to each other like magnets
Does an F- cell have a genome?
Yes, it simply lacks the fertility factor plasmid
Is the F factor capable of replicating itself?
Yes, it makes a copy of itself during conjugation to send to the F- cell
Do cells break down during conjugation?
No, broken cells are involved in transformation
At the end of conjugation, how many F+ cells do you have?
2, the original and the newly make F+ cell
Do you have F- cells at the end of conjugation?
No, during conjugation F- cells become F+ after reviving the fertility factor
What is the F factor?
It is the fertility factor in bacterial cells that allows them to make a sex pilus and exchange DNA and plasmids
Can an F- cell exchange plasmids?
No, you need the F factor to produce the sex pilus required in sharing genetic material
What is a plasmid?
It is a genetic structure in the bacterial cell that can code for things and replicate independently from the chromosomes
Name 3 plasmids
1. Fertility factor
2. R (resistance) plasmids (RTF + R genes)
How often can genome recombination happen in conjugation?
Very rarely, 1/100,000
Can a cell have more than 1 plasmid?
Yes! It can have as many as it likes
What does HFR stand for?
High Frequency Recombination
Define High Frequency Recombination (HFR)
It is a bacterial cell that has incorporated its F factor into its genome and will pass part of the genome to pass through the sex pilus during recombination
How long does HFR take?
About 90-100 minutes
What is an episome?
A genome that has the fertility factor incorporated in it
What is it called when a fertility factor is incorporated into a genome?
When will you have the genome pass through the sex pilus?
during HFR (high frequency of recombination)
During HRF, does the episome pass through the sex pilus first?
No, it will pass through last, if at all
Does the genome break apart during HFR?
It does in the donor cell
How many F+ cells do you have after HFR?
One, the recipient cell doesn't get the F factor
How many F- cells do you have after HFR?
One, the recipient cell doesn't get the F factor
True or false: Only 1 plasmid can be exchanged during conjugation
False, many plasmids can be exchanged
True or False : Lots of plasmids can be exchanged during conjugation
What does RTF stand for?
Resistance Transfer Factors
What kind of gram cell is most likely to exchange resistance factors?
Where does the exchange of resistance factors happen most frequently?
True or False: Gram - cells do not commonly exchange resistance factor
What is Beta-Lactamase?
An enzyme that can break down antibiotics such as penicillin or cephalosporine
What does cephalospoinase break down?
What breaks down cephalospoines?
Name 3 bacteria that commonly exchange Beta-Lactamase
3. Nisseria gonorrhea
How is Beta-Lactamase transferred?
What is transduction?
The process of transferring genetic material between cells through bacteriophages
What is a bacteriophage?
A virus with bacterial DNA
Define Lysogenic Conversion
A method of recombination, but that transfers viral DNA instead of bacterial DNA
Why is lysogentic conversion bad?
It makes bacteria very dangerous
Name some cells that have been affected by lysogentic conversion
1. Clostridium botulinum (a Type A poision)
2. Corynebacterium Diphteriae (has a toxin that damages the heart)
3. Streptococcus pyogenes (which can cause Scarlet Fever due to it producing an erythrogenic toxin)
How has Lysogenic conversion made Clostridium botulinum worse?
Its made it into a Type A poison, potent enough to kill all the humans with a cup of it
How has lysogenic conversion made Corynebacterium diphteriae worse?
Has allowed it to make a toxin that damages the heart
How has lysogenic conversion made streptococcus pyogenes worse?
Had given it the ability to make an erythrogenic toxin which causes scarlet fever
What cause Scarlet fever?
What is the difference between Transduction and Lysogenic conversion?
Transduction transfers bacterial DNA and lysogenic conversion transfers viral DNA