topic 4 - bacterial recombination Flashcards
1
Q
In all organisms, ______ introduce random variation
A
mutations
2
Q
recombination is?
A
new combinations of genes in individuals in the population
3
Q
eukaryotes: Variation also introduced by:
A
- random assignment of chromosomes during meiosis
- random gamete fusion
- random mate choice
4
Q
bacteria:______ gene transfer during reproduction DOES NOT allow for genetic variability
A
vertical
5
Q
vertical gene transfer
A
= reproduction (binary fission)
- asexual
- no variability
- passing cells to daughter cell
6
Q
horizontal gene transfer
A
- recombination (new gene combination in existing cells)
- doesn’t increase cell number
- cell of same gen. passes gene to existing cell
7
Q
types of recombination
A
- transformation
- transduction (2 types)
- conjugation (2 types)
8
Q
what helps bacteria maximize genetic variation?
A
- new DNA received will always replace existing DNA (old DNA recycled)
- plasmids move freely into both the genome and other plasmids (recombination more likely with abnormal excision of plasmid genes)
9
Q
abnormal excision
A
when plasmids pull out imperfectly
10
Q
Griffith experiment (transformation)
A
- injected 3 different variations of bacteria into mice
- combined the two injections that resulted in survival for the mouse and injected them into a mouse
- found that the mouse died
11
Q
Transformation
- donor cell
- recipient cell
- genes gained
- how do genes travel between cells
A
- donor cell: dead
- recipient cell: competent & same species unless plasmid absorbed
- genes gained: random (genome or plasmid)
- travels: floating in watery medium and bumps into the recipient
12
Q
conjugation
- donor cell
- recipient cell
- genes gained
- how do genes travel between cells
A
- donor cell: F+
- recipient cell: F-
- genes gained: copy of f plasmid
- travel: sent along sex pili
13
Q
Hfr conjugation
- donor cell
- recipient cell
- genes gained
- how do genes travel between cells
A
- donor cell: F+ and Hfr donor
- recipient cell: F-
- genes gained: genes closest to origin from donor
- travel: sex pili pulls cells together
14
Q
Hfr conjugation -> transfer of entire gene circle is partial due to _______
A
time limits
15
Q
generalized transduction
- life cycle involved
- mistake in what stage
- genes gained
A
- lytic
- assembly -> random fragments of host 1 DNA injected into host 2
- random gene
16
Q
specialized transduction
- life cycle involved
- mistake in what stage
- genes gained
A
- lysogenic
- synthesis -> accidentally pulls out genes next to provirus
- specific genes beside viral DNA
17
Q
generalized transduction
- donor cell
- recipient cell
- genes gained
- how do genes travel between cells
A
- must be injected by a phage
- must be infected by transducing phage
- random gene
- phage capsid carries genes
18
Q
specialized transduction
- donor cell
- recipient cell
- genes gained
- how do genes travel between cells
A
- must be injected by a phage
- must be infected by transducing phage
- specific genes besides viral DNA
- phage capsid carries genes
