GENETICS EXAM AND ITS CORRECT
COMPLETE SOLUTIONS
DNA fragments cut by restriction enzymes can form
two types of ends. What are these ends called?
Sticky and blunt ends
The restriction enzyme HincII was isolated from the
bacterium Haemophilas influenza. The DNA sequence
cut by this enzyme is shown here. (Note that Y means
any pyrimidine--C or T--and that R means any purine--
A or G.)
CTY*RAC
GAR*YTG
HincII is a blunt-end cutter that cuts after the Y.
The lambda phage genome is 48.5 kb in size and has
50% GC content.
Approximately how many times would you expect
HincII to cut lambda phage DNA?
48
You can use the multiplication rule to calculate the
probability that all of the bases in the cut site sequence will
occur in order in the genome:
1/4 x 1/4 x 1/2 x 1/2 x 1/4 x 1/4 = 0.001
Then, to determine the number of cut sites expected in the
lambda genome, you need to multiply this probability by
,the size of the genome:
48,500 x 0.001 = 48
You cut a gene of interest with HincII and would like to
insert it into the multiple cloning site (MCS) of a
plasmid. The plasmid's MCS contains the cut sites
listed below.
Which of these sites could you use to insert the gene
of interest? Select all that apply.
a)GTA*TAC
CAT*ATC
b)GGT*ACC
CCG*TGG
c)G*TYRAC
CGRYT*G
d)GT*CAAC
CAGT*TG
e)GTC*AAC
CTG*TTG
f)none of these sites
a,b,e
Vectors are
plasmids, bacteriophages, or cosmids that receive,
through ligation, a piece or pieces of foreign DNA
Resctriction enzymes
cut DNA at specific sites
Host cells
, express foreign genes introduced in the recombinant DNA
What role does DNA ligase perform in a DNA cloning
experiment? How does the action of DNA ligase differ
from the function of restriction enzymes?
DNA ligase generates the covalent bonds of the
phosphodiester backbone, while restriction enzymes break
those bonds.
Following are four processes common to most
cloning experiments:
A) transforming bacteria
B) plating bacteria on selective medium
C) cutting DNA with restriction endonucleases
D) ligating DNA fragments
Place components of this list in the order in which
they would most likely occur during a cloning
experiment.
C,D,A,B
What is the definition of a clone?
an identical copy of a DNA molecule, a cell, or an
organism
Some vectors such as pUC18 and others of the pUC
series contain a large number of restriction enzyme
sites clustered in one region. Which term is given to
this advantageous arrangement of restriction sites?
multiple cloning site (MCS)
Which features make yeast artificial chromosomes
(YACs) an excellent cloning tool?
In their linear form, YACs contain telomeres at each end
for stability, an origin of replication, and they can be used
COMPLETE SOLUTIONS
DNA fragments cut by restriction enzymes can form
two types of ends. What are these ends called?
Sticky and blunt ends
The restriction enzyme HincII was isolated from the
bacterium Haemophilas influenza. The DNA sequence
cut by this enzyme is shown here. (Note that Y means
any pyrimidine--C or T--and that R means any purine--
A or G.)
CTY*RAC
GAR*YTG
HincII is a blunt-end cutter that cuts after the Y.
The lambda phage genome is 48.5 kb in size and has
50% GC content.
Approximately how many times would you expect
HincII to cut lambda phage DNA?
48
You can use the multiplication rule to calculate the
probability that all of the bases in the cut site sequence will
occur in order in the genome:
1/4 x 1/4 x 1/2 x 1/2 x 1/4 x 1/4 = 0.001
Then, to determine the number of cut sites expected in the
lambda genome, you need to multiply this probability by
,the size of the genome:
48,500 x 0.001 = 48
You cut a gene of interest with HincII and would like to
insert it into the multiple cloning site (MCS) of a
plasmid. The plasmid's MCS contains the cut sites
listed below.
Which of these sites could you use to insert the gene
of interest? Select all that apply.
a)GTA*TAC
CAT*ATC
b)GGT*ACC
CCG*TGG
c)G*TYRAC
CGRYT*G
d)GT*CAAC
CAGT*TG
e)GTC*AAC
CTG*TTG
f)none of these sites
a,b,e
Vectors are
plasmids, bacteriophages, or cosmids that receive,
through ligation, a piece or pieces of foreign DNA
Resctriction enzymes
cut DNA at specific sites
Host cells
, express foreign genes introduced in the recombinant DNA
What role does DNA ligase perform in a DNA cloning
experiment? How does the action of DNA ligase differ
from the function of restriction enzymes?
DNA ligase generates the covalent bonds of the
phosphodiester backbone, while restriction enzymes break
those bonds.
Following are four processes common to most
cloning experiments:
A) transforming bacteria
B) plating bacteria on selective medium
C) cutting DNA with restriction endonucleases
D) ligating DNA fragments
Place components of this list in the order in which
they would most likely occur during a cloning
experiment.
C,D,A,B
What is the definition of a clone?
an identical copy of a DNA molecule, a cell, or an
organism
Some vectors such as pUC18 and others of the pUC
series contain a large number of restriction enzyme
sites clustered in one region. Which term is given to
this advantageous arrangement of restriction sites?
multiple cloning site (MCS)
Which features make yeast artificial chromosomes
(YACs) an excellent cloning tool?
In their linear form, YACs contain telomeres at each end
for stability, an origin of replication, and they can be used
