Chapter 7 - Genetic Transfer and Mapping in Bacteria Flashcards
Are bacteria usually haploid or diploid?
Haploid
Bacteria reproduce asexually through this method
Binary fission
In this process, a segment of bacterial DNA is transferred from one bacterium to another
Genetic transfer (or horizontal genetic transfer)
These are viruses that infect bacteria
Bacteriophages
Do bacteriophages contain their own genetic material?
Yes
Like sexual reproduction in eukaryotes, genetic transfer in bacteria enhances this
Genetic diversity
What are three ways in which genetic material can transfer from one bacterium to another?
Conjugation, transduction, transformation
This method of genetic transfer involves direct physical contact between bacteria
Conjugation
This method of genetic transfer involves bacteriophages
Transduction
This method of bacterial genetic transfer involves uptake from the environment
Transformation
In conjugation, this circular segment of DNA is transferred to a recipient cell
Plasmid
In transformation, is the donor cell alive or dead?
Dead
Genetic transfer in bacteria was discovered in 1946 by these two scientists
Joshua Lederberg and Edward Tatum
What are the two different strains of E. coli that Joshua Lederberg and Edward Tatum studied?
Auxotrophs and prototrophs
This strain of E. coli cannot synthesize a particular nutrient and therefore need it in their growth medium
Auxotrophs
This strain of E. coli make all their nutrients from components in their growth medium
Prototrophs
This scientist showed that bacterial strains must make physical contact for transfer of genetic material to occur
Bernard Davis
Bernard Davis used this apparatus to show that bacteria must make physical contact to transfer genetic material
U-tube
This apparatus has a filter at the bottom with pores that are large enough to allow the passage of genetic material but small enough to prevent the passage of bacterial cells
U-tube
Can all species of bacteria conjugate?
No
Can only certain strains of bacteria act as donor cells in conjugation?
Yes
Certain donor strains of E. coli contain this small circular piece of DNA
F factor (fertility factor)
Bacteria strains containing an F factor are designated this
F+
Bacteria strains lacking an F factor are designated this
F-
Genes that play a role in DNA transfer are named either of these two prefixes
tra or trb followed by a capital letter
What initiates conjugation between bacteria cells?
Contact between donor and recipient cells
These act as attachment sites for F- minus bacteria onto F+ bacteria
Sex pili (or F pili)
Once contact is made and the pili shorten, donor and recipient bacteria cells are drawn together and this forms between the two cells
Conjugation bridge
During conjugation, this recognizes the origin of transfer (DNA sequence) and makes a cut in the DNA
Relaxosome
This protein remains bound to the end of the T-DNA after most accessory proteins of the relaxosome are released
Relaxase