BI 255 EXAM QUESTIONS AND ANSWERS
LATEST UPDATE
Would you consider short tandem repeats to be considered essential regions?
no, I would consider them nonessential regions because they do not code for or bind
proteins
Are short tandem repeats the same in every person?
Yes and No
- Yes: everybody has the same sequence of short tandem repeats
- No: the number of repeats varies between people
At every chromosomal locus, how many short tandem repeats are there?
two
- because there are two copies of every chromosome
Why are short tandem repeats considered to be hyper variable?
the number of repeats of a short sequence varies between people
What is CODIS used for?
CODIS is the national DNA database for convicted felons
How many short tandem loci does CODIS look at?
13 different chromosomal positions
In CODIS, why do we look at 13 different loci and not 2?
it is more probable that multiple people will share the same 2 short tandem repeats,
than sharing 13 STRs
What is the probability that 2 people will have the same number of short tandem
repeats at 13 different loci?
1 in 7 quadrillion
What is the one exception to the idea that 2 people can not share 13 different loci
of short tandem repeats?
identical twins
- they would have the same exact DNA, so their short tandem repeats would be the
exact same at ALL 13 locations looked at in CODIS
What can the short tandem repeats, documented in CODIS, be used to
determine?
1. paternity/maternity tests
2. determining crime suspect
Who was BTK?
Dennis Rader
What is a chimera in greek mythology?
someone with a lions head, snake tail and the body of a goat
What makes up a chimera?
two (or more) separate individuals smushed into one
- they have at least two different genotypes that are distinct from one another
Lydia Fairchild
Karen Keegan
, Are chimera individuals, considered intersex individuals?
Yes, if their genetic makeup is XX and XY
No, if their genetic makeup is XX and XX or XY and XY
How would you distinguish between a mosaic caused by nondisjunction, like
Foekje Dilemma, from a mosaic caused by chimerism, like Karen Keegan?
Nondisjunction - at any place in the body, there will be two different genotypes
Chimerism - different parts of the body have different genotypes but one location only
has one genotype
If an individual decides to learn more about their familial ancestry through a
commercial DNA sequencing company, like Ancestry.com or 23andMe, once they
send out their saliva to the company, does it still belong to the individual?
once your DNA leaves your body, you give up your rights
DNA replication is ____________
semiconservative
What does it mean to say that DNA replication is semiconservative?
half of the molecule is old, and half of the molecule is new
In what direction does DNA polymerase make DNA?
5' to 3'
Why does DNA have to be built 5' to 3'?
because of the structure of DNA polymerase
- can only attach/bind to the 3' end of its ligand (DNA)
DNA polymerase has an active site so as a result it can only attach one way to its ligand
What is the ligand of DNA polymerase?
DNA - specifically the 3' end of DNA
How would you describe the shape of DNA polymerase?
as a horseshoe
Because DNA polymerase is an enzyme, it performs catalytic behaviors. What
does DNA polymerase catalyze?
catalyzes the formation of phosphodiester bonds (i.e. the linkages between nucleotides)
What does DNA polymerase need to catalyze the formation of phosphodiester
bonds?
needs the 3' end and a free nucleotide (dNTP)
- free nucleotides need to be incorporated into the growing strand because DNA
polymerase needs the 3' end and free nucleotides to attach. when shape is just right
(has correct free nucleotides) then it will fuse the free nucleotides and form
phosphodiester bond
When DNA polymerase forms a phosphodiester bond, what is released?
two phosphate groups
What specific types of DNA polymerase are responsible for most DNA
replication?
DNA polymerase epsilon (ε) and delta (δ)
Where does DNA replication start?
LATEST UPDATE
Would you consider short tandem repeats to be considered essential regions?
no, I would consider them nonessential regions because they do not code for or bind
proteins
Are short tandem repeats the same in every person?
Yes and No
- Yes: everybody has the same sequence of short tandem repeats
- No: the number of repeats varies between people
At every chromosomal locus, how many short tandem repeats are there?
two
- because there are two copies of every chromosome
Why are short tandem repeats considered to be hyper variable?
the number of repeats of a short sequence varies between people
What is CODIS used for?
CODIS is the national DNA database for convicted felons
How many short tandem loci does CODIS look at?
13 different chromosomal positions
In CODIS, why do we look at 13 different loci and not 2?
it is more probable that multiple people will share the same 2 short tandem repeats,
than sharing 13 STRs
What is the probability that 2 people will have the same number of short tandem
repeats at 13 different loci?
1 in 7 quadrillion
What is the one exception to the idea that 2 people can not share 13 different loci
of short tandem repeats?
identical twins
- they would have the same exact DNA, so their short tandem repeats would be the
exact same at ALL 13 locations looked at in CODIS
What can the short tandem repeats, documented in CODIS, be used to
determine?
1. paternity/maternity tests
2. determining crime suspect
Who was BTK?
Dennis Rader
What is a chimera in greek mythology?
someone with a lions head, snake tail and the body of a goat
What makes up a chimera?
two (or more) separate individuals smushed into one
- they have at least two different genotypes that are distinct from one another
Lydia Fairchild
Karen Keegan
, Are chimera individuals, considered intersex individuals?
Yes, if their genetic makeup is XX and XY
No, if their genetic makeup is XX and XX or XY and XY
How would you distinguish between a mosaic caused by nondisjunction, like
Foekje Dilemma, from a mosaic caused by chimerism, like Karen Keegan?
Nondisjunction - at any place in the body, there will be two different genotypes
Chimerism - different parts of the body have different genotypes but one location only
has one genotype
If an individual decides to learn more about their familial ancestry through a
commercial DNA sequencing company, like Ancestry.com or 23andMe, once they
send out their saliva to the company, does it still belong to the individual?
once your DNA leaves your body, you give up your rights
DNA replication is ____________
semiconservative
What does it mean to say that DNA replication is semiconservative?
half of the molecule is old, and half of the molecule is new
In what direction does DNA polymerase make DNA?
5' to 3'
Why does DNA have to be built 5' to 3'?
because of the structure of DNA polymerase
- can only attach/bind to the 3' end of its ligand (DNA)
DNA polymerase has an active site so as a result it can only attach one way to its ligand
What is the ligand of DNA polymerase?
DNA - specifically the 3' end of DNA
How would you describe the shape of DNA polymerase?
as a horseshoe
Because DNA polymerase is an enzyme, it performs catalytic behaviors. What
does DNA polymerase catalyze?
catalyzes the formation of phosphodiester bonds (i.e. the linkages between nucleotides)
What does DNA polymerase need to catalyze the formation of phosphodiester
bonds?
needs the 3' end and a free nucleotide (dNTP)
- free nucleotides need to be incorporated into the growing strand because DNA
polymerase needs the 3' end and free nucleotides to attach. when shape is just right
(has correct free nucleotides) then it will fuse the free nucleotides and form
phosphodiester bond
When DNA polymerase forms a phosphodiester bond, what is released?
two phosphate groups
What specific types of DNA polymerase are responsible for most DNA
replication?
DNA polymerase epsilon (ε) and delta (δ)
Where does DNA replication start?
