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2 Bacterial and Eukaryotic genetics
June 11
38
Biology
Undergraduate 2
06/11/2015

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Term
How do bacteria produce genetic diversity?
Definition
Replication and genetic transfer
Term
How does genetic diversity occur in replication?
Definition
Errors that occur in DNA replication
-DNA replicates frequently in bacteria
Term
How does genetic diversity occur in genetic transfer?
Definition
Exchange portions of their genomes
Term
What is halobacterium?
Definition
an archaea that has about 1/3 of their genome come from other bacteria
Term
What does genetic transfer in bacteria allow?
Definition
genetic recombination
Term
What are three types of genetic transfer in bacteria
Definition
Transduction
Conjugation
Transformation
Term
What is transduction?
Definition
Virus mediated transfer of DNA from one cell to another
No direct contact between cells needed
Term
What is conjugation?
Definition
- Direct transfer of DNA from one cell to another (Requires physical connection-- Sex pilus – modified fimbria
- Involves transfer of ‘F factor’- Contains genes for conjugation and a replication start site
-Can be found in two possible locations:
 On plasmid
 On chromosome
A cell without F factor (‘F-’) is the recipient
Term
What does conjugation require?
Definition
physical connection
Term
Where can the f factor be found?
Definition
on the plasmid
on chromosome
Term
What is the recipient when compared to f factor?
Definition
A cell without F factor (F-)
Term
Describe F+ conjugation on the plasmid process
Definition
F factor is located on a special F plasmid (Cell with F plasmid is 'F+')
Sex pilus forms connecting cells
One strand of F plasmid crosses to recipient ( 'rolling circle' replication in donor)
Transferred DNA serves as template for synthesis of other strand, is circularized to form F plasmid in recipient cell, making it F+
Other genes can insert into plasmid,pass along with F factor
Term
Describe Hfr and the process
Definition
F factor is located on genome
Sex pilus forms, connecting cells
One strand of chromosome crosses to recipient
('rolling circle' replication in donor)
Genome is too bug, take too long to pass in its entirety: amount transferred is time-dependent (used to make early map of E. coli genome, in minutes)
Transferred DNA recombines with recipient genome ( some incorporated, some degraded)
Term
What are the two processes called when the f factor is positive?
Definition
F+ conjugation= plasmid
Hfr conjugation=chromosome
Term
What is transformation in bacteria?
Definition
Bacteria pick up DNA from environment
Term
What are two examples of transformation in bacteria?
Definition
-One bacterium dies and another scavenges pieces of its DNA
-Can be trans-species (sushi) gut bacteria is passed down after being picked up after eating by parents
Term
How can transformation occur in eukaryotes?
Definition
mechanism of germ-line incorporation unclear
Term
What is polymorphism?
Definition
Th presence of multiple traits in a population
Term
What is a character?
Definition
a heritable feature that is polymorphoc
ex) fur color or earlobe attachment
Term
What is a trait?
Definition
the individual variants of a character
ex)black fur vs orange fur
attached earlobe vs unattached
Term
What is preformationism?
Definition
Belief that the progeny are just little copies of the parent
Term
What is the blending hypothesis?
Definition
Belief that children are intermediate between the two parents
-represent the product of averaging all of the traits of parents
-could not be unblended-would lead to uniform population
-children would all be at the same half-way point
-children could never have a characteristic not seen in parents, or more extreme than those seen in parents
Term
What is Mendelian genetics?
Definition
Named for Gregor Mendel
Studied genetics of pea plant
Term
Whys study pea genetics?
Definition
-Good model system
Many distinct varieties
Easy to self and cross fertilize
Fast generation time
Many offspring
Term
What does mendelian genetics look at?
Definition
Genetic variation derives form different versions of the same gene (allele)
Diploid organisms have two alleles
One on each paired chromosome, one from each parent
Term
What is an allele?
Definition
different versions of the same gene
Term
What are the results of mendelian genetics?
Definition
the characteristics of some alleles dominate over others
-not blending, but all or nothing
Dominant
Recessive
Term
What is the law of segregation?
Definition
In diploid organisms, the two alleles are inherited from different parents and end up in different gametes
-traits passed as units
-no blending
-studied through controlled breeding
(Carry out a specific cross, observe results)
Term
How do you follow the law of segregation?
Definition
By following over successive generations
P generation
F1 generation
F2 generation
Term
What is P generation?
Definition
parental units
Term
What is F1 generation?
Definition
First 'filial'
Term
What is F2 generation?
Definition
second 'filial'
from self-cross between F1
Term
What is a monohybrid cross?
Definition
◦ Study of the genetics of a single trait
Term
What is a phenotype?
Definition
observed trait (visible characteristics)
Term
What is a genotype?
Definition
genetic makeup responsible for observed trait (what the different traits are)
Term
What is homozygous?
Definition
both alleles for a gene are the same
Term
What is heterozygous?
Definition
The two alleles are different
Term
What does the letter usually represent when describing traits?
Definition
 Letter usually represents trait that differs from what is normal for a
population (‘wild type’)
 Capital is for dominant
 Small of same letter for
recessive
 ‘+’ sometimes used to
represent wild type
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