Flashcards in Exan Dos Deck (45)
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1
Proof of crossing over
Creighton and McClintock
2
What did creighton and McClintock conclude
Crossing over does involve a physical exchange between homologous chromosomes
3
Advantages of using bacteria for genetic studies
Lots of progeny
Can be genetically engineered
Reproduction is rapid
Growth is easy with little space
Easy to isolate
4
Prototroph
Can grow on minimal media
5
Auxotroph
Mutant that requires additional nutrients
6
Lederberg and Tatum
Conducted an experiment to determine if bacteria can transfer genetic material
7
Purpose of U tube experiment
To understand if bacteria must touch in order to exchange genetic information
8
Davis
U tube experience for to understand if cell contact is required for transfer of genetic information
9
Conjugation
Temporary fusion of two single cell organisms for the sexual exchange of genetic material
10
Bacteria cells that can transfer genetic material through fusion
F+ and F- cells
11
F-
Recipient cell
12
F+
Contains F factor and donates through pili hat contact F-
13
Process of Conjugation
Pilus of F+ come in contact with F-
Conjugation tube forms
One strand of F factor is nicked and the 5’ end leads the way to the F- cell
Replication of the F factor occurs
14
Benzer experiment
Wondered if mutations were all in same gene or if several genes were controlling lysis
Coinfext bacterial with two strains of bacteriophage and see if normal plaques are produced
15
Population genetics
Study of inherited variation within and between populations over time and space
16
CIs
Mutation one same chromosome
17
Trans
Mutation on different chromosomes
18
Cistron
Place where complementation cannot occur (gene)
19
Two mutations in same gene
Alleles
20
Two mutations on different genes
Nonalleles
21
Lytic cycle
Phage infects
Injects genetic material
Takes over
Replicates
Creates new phages
Lysis of cell
22
Plaque
Seen on lawn of bacteria when lysis occurs
23
Lysogenic cell
Bacterial cell with a prophage
24
Prophage
A bacterial cell with a phage integrated into the chromosome
25
Life cycle of a temperate phage
Lytic or lysogenic
26
How do we use conjugation to map?
Combine several Hfr x F- makings
27
Interrupted Mating
Combining several HFR x F- pairs to map circular bacteria because different Hfr strands integrate in different places if the bacterial chromosome and will begin transfer af different places and sometimes different directions
28
F’ cells
F factor within an HFR pops out of the bacterial chromosome to produce an F’ cell
29
F’ xF-
F’ merezygote (partial diploid)
30
Transformation
Exogenous DNA transfers genes to competent bacterial cell and brings about heritable change in the cell
31
Result of transformation
Only one daughter cell is transduced
32
How can we use translation for genetic mapping
Cotransformation to determine if genres are located near each other
33
Generalized transduction
Bacteria are infected with phage
Bacterial chromosome is fragmented and some of the genes become incorporated into a few phages
The cell lysis releases the phages to attach and release bacterial genetics instead of the phage genetics and create a transduced bacterial cell
34
How can we use generalized transduction for mapping?
Two genes co transduce if they are close together
35
Specialized transduction
Prophage pops out of bacterial chromosome and takes one or more genes with it
The progeny virus transfer these genes when infecting other cells
36
How can we use specialized transduction for genetic mapping
Not useful since the only genes are affects are those next to the integration site
37
Cell contact required in conjugation?
Yes
38
Cell contact required in transformation?
No
39
Cell contact required in transduction?
No
40
Conjugation sensitive to DNase?
No
41
Transformation sensitive to DNase?
Yes
42
Transduction sensitive to DNase?
Yes
43
Hardy Weinberg law
Allele and genotypes frequencies will arrive at and remain at equilibrium frequencies after one generation of random mating of all sssumotions are met
44
Assumptions of hardy Weinberg
Infinitely large population
Random mating
No selection (all genotypes equally fit)
No migration
No mutation
45
