GN 311 EXAM 2 QUESTIONS WITH VERIFIED
ANSWERS
What is the law of independent assortment? - Answers - each pair of alleles segregates
independently of the other pairs of alleles during gamete formation regardless of
location.
How does linkage affect independent asortment - Answers - linkage violates
independent assortment but not random segregation
The recombination frequency is proportaional to what? - Answers - distance between
the genes, this makes up the basis for genetic mapping, measured in 1% equals 1 cM
At what distance does linkage not occue and genes are considered the assort
independently - Answers - 50 cM
when making a 3 point map, hwat do you have to do first and why? - Answers - a
statistical test must indicates linkage. you do a chi squared test with recombinant and
parent types. if independent assortment occurs, then both would be equal.
How do you find the coeficient of coincidence - Answers - the observed number of dco
over the expected number
What is the interference? - Answers - 1 - coefficient of coincidence
Explain mapping using genome wide association studies (GWAS) - Answers - using
single neucleotide polymorphisms or variations are a single base in the DNA. uses the
information from 2 groups and sees if there is a difference more signifigant in the
experimental group. may be linked to a disease gene
What is a prototroph? - Answers - wild type that can grow on minimal media
What is an auxotroph? - Answers - a mutant strain that requires additional nutrients to
survive
What are the 3 types of gene transfer in bacteria - Answers - conjugation,
transformation and transduction.
What do we learn from auxotroph mixing experiments - Answers - 2 mutant strains that
cant live on minimal media can be mixed and some prototrophic colonies are formed.
performed by lederberg and tatum in 1946
, What did we learn from auxotroph u-tube experiments - Answers - performed by
bernard dazis in 1950. the media around cells can mix but the cells never conact
eachother, no protophtrophes
What id conjugation? - Answers - the temporary fusion of 2 single cell organisma for the
sexual exchange of genetic material
What are the 2 cell types involved in conjugation and explain them - Answers - F+
contains an episome called the F factor and is the donor cell. F- is the recipient cell
explain the process of conjugation - Answers - a pilli from the F+ cell contacts the F- cell
and a conjugation tube forms and 1 strand of the f factor is nicked and brought to the f-
cell from the 5' end. replication of of the f factor returns it to the double stranded state
What is a Hfr cell? - Answers - high frequency of recombination due to integration of f
factor in to the bacterial chromosome due to crossing over between them. results in
change from F+ cell to Hfr cell
Explain Hfr and F- mating - Answers - part of the f factor leads the way into the f- cell
and the transfered stand is replicated. the recipient cell experiences recombination
between new dna and original bacterial chromosomes. the recipient may have new
genetic variation but will not have the F Factor or be F+/Hfr
What is an interrupted mating experiment? - Answers - different hfr strains will integrate
in different places of the chromosomes and begin to transfer at different times and
difections. you can use this information (time and order of transfer) to map the bacterial
chromosome
What is an f' cell? - Answers - the f factor pops back out fo the bacterial chromosomes
and may carry some bacterial genes with it. can mate with an f- cell to make a
merozygote that is a partial diploid
Explain bacterial transformation? - Answers - exogenous DNA transfers genes to
competent bacterial cells and brings about heritable change in cells, a dna fragment
enters the cell and pairs with the bacterial chromosome and recombination takes place.
the remainder of the dna fragments is degraded. when the cell divides on ly 1 of the
daughter cells is transformed because only 1 strand of the original bacterial
chromosome is altered
how can you use transformation to determine if genes in bacteria are located near
eachother? - Answers - dna from a donor cell is fragmented and taken up by the
recipient cell. by looking at the frequency of recombination and which alleles
recombinate more frequently together you can see if they are located closer together
What is a bacteriophage? - Answers - A virus that infects bacteria
ANSWERS
What is the law of independent assortment? - Answers - each pair of alleles segregates
independently of the other pairs of alleles during gamete formation regardless of
location.
How does linkage affect independent asortment - Answers - linkage violates
independent assortment but not random segregation
The recombination frequency is proportaional to what? - Answers - distance between
the genes, this makes up the basis for genetic mapping, measured in 1% equals 1 cM
At what distance does linkage not occue and genes are considered the assort
independently - Answers - 50 cM
when making a 3 point map, hwat do you have to do first and why? - Answers - a
statistical test must indicates linkage. you do a chi squared test with recombinant and
parent types. if independent assortment occurs, then both would be equal.
How do you find the coeficient of coincidence - Answers - the observed number of dco
over the expected number
What is the interference? - Answers - 1 - coefficient of coincidence
Explain mapping using genome wide association studies (GWAS) - Answers - using
single neucleotide polymorphisms or variations are a single base in the DNA. uses the
information from 2 groups and sees if there is a difference more signifigant in the
experimental group. may be linked to a disease gene
What is a prototroph? - Answers - wild type that can grow on minimal media
What is an auxotroph? - Answers - a mutant strain that requires additional nutrients to
survive
What are the 3 types of gene transfer in bacteria - Answers - conjugation,
transformation and transduction.
What do we learn from auxotroph mixing experiments - Answers - 2 mutant strains that
cant live on minimal media can be mixed and some prototrophic colonies are formed.
performed by lederberg and tatum in 1946
, What did we learn from auxotroph u-tube experiments - Answers - performed by
bernard dazis in 1950. the media around cells can mix but the cells never conact
eachother, no protophtrophes
What id conjugation? - Answers - the temporary fusion of 2 single cell organisma for the
sexual exchange of genetic material
What are the 2 cell types involved in conjugation and explain them - Answers - F+
contains an episome called the F factor and is the donor cell. F- is the recipient cell
explain the process of conjugation - Answers - a pilli from the F+ cell contacts the F- cell
and a conjugation tube forms and 1 strand of the f factor is nicked and brought to the f-
cell from the 5' end. replication of of the f factor returns it to the double stranded state
What is a Hfr cell? - Answers - high frequency of recombination due to integration of f
factor in to the bacterial chromosome due to crossing over between them. results in
change from F+ cell to Hfr cell
Explain Hfr and F- mating - Answers - part of the f factor leads the way into the f- cell
and the transfered stand is replicated. the recipient cell experiences recombination
between new dna and original bacterial chromosomes. the recipient may have new
genetic variation but will not have the F Factor or be F+/Hfr
What is an interrupted mating experiment? - Answers - different hfr strains will integrate
in different places of the chromosomes and begin to transfer at different times and
difections. you can use this information (time and order of transfer) to map the bacterial
chromosome
What is an f' cell? - Answers - the f factor pops back out fo the bacterial chromosomes
and may carry some bacterial genes with it. can mate with an f- cell to make a
merozygote that is a partial diploid
Explain bacterial transformation? - Answers - exogenous DNA transfers genes to
competent bacterial cells and brings about heritable change in cells, a dna fragment
enters the cell and pairs with the bacterial chromosome and recombination takes place.
the remainder of the dna fragments is degraded. when the cell divides on ly 1 of the
daughter cells is transformed because only 1 strand of the original bacterial
chromosome is altered
how can you use transformation to determine if genes in bacteria are located near
eachother? - Answers - dna from a donor cell is fragmented and taken up by the
recipient cell. by looking at the frequency of recombination and which alleles
recombinate more frequently together you can see if they are located closer together
What is a bacteriophage? - Answers - A virus that infects bacteria
