: Genetic Engineering
refer to the following list. Answers may be used more than once, or not at all.
Allows for rapid production
many copies of
Seal gaps in sugar
es of newly synthesized DNA molecules.
Used to describe genetically modified organisms.
A group of genetically identical organisms or cells.
Proteins made by bacterial cells and used by biologists t
o cut the sugar
backbones of DNA molecules.
Separates fragments of DNA by the size of the molecules.
Bind to DNA at a specific nucleotide sequence and enable
specific sequences of
DNA from larger DNA molecules (such as chromosomes).
refer to the diagram below of some of the key components found inside a
Which of the following i
s true of the gel electrophoresis shown?
the power source has not been turned on yet
the three wells contained the same samples DNA molecules
Well #1 had fewer molecules of DNA than Well 2 or 3
Well #3 had more different sized molecules of DNA than Well 1
Which of the following is true of gel electrophoresis?
the longer a molecule of DNA, the slower it will move through agarose gel
DNA molecules with unknown base sequences are “read” by gel electrophoresis
gel electrophoresis separated DNA molecules b
ased on their base sequence
All of the above are true.
What causes the DNA to migrate from the wells toward the positive electrode?
DNA is positively charged too, and so was attracted to the positive electrode
DNA is negatively charged, and so was attra
cted to the positive electrode
DNA is polar and forms hydrogen bonds with the positive electrodes
DNA is electrically charged, and so cycles through an electric field
Which of the following statements is TRUE about the band of molecules labeled
ains DNA fragments that are shorter than the ones in any of the other bands.
It contains fewer DNA molecules than any of the other bands from lane 3.
It contains more negatively charged particles than any other band on the gel.
It contains fewer genes than
any of the other bands on the gel.
Two different molecules of DNA are cut with the same restriction enzyme. If the restriction enzyme used
produces “sticky ends” when it cuts, which of the following will be true?
the cut pieces from the two different mol
ecules will be able to hydrogen bond with each other
the cut pieces will have the same nucleotide sequences at the site where the enzyme made the cuts
the original molecules of DNA may have been cut in more than one place
All of the above are true.
Path of DNA
Wells containing soluti
with DNA molecules of
Bands of DNA
PCR, which step in the process is necessary to separate the two strands of a DNA molecule so that
DNA polymerase enzymes can use each as a template for making complementary copies of both?
addition of free nucleotides
f short “primers”
(D) cutting with restriction enzymes
During PCR, why are DNA polymerase enzymes from the heat
the bacterium produces enzymes that can work equally fast in warm or cool temperatures
m produces enzymes that are not denatured by temperatures up to 100C
the enzymes are denatured by heat and thus don’t interfere with the production of multiple copies of DNA
the enzymes are more accurate when copying DNA sequences than ones from most other
refer to the diagram of the restriction sites for several restriction enzymes. The arrows show where the
enzyme breaks the strands of a double helix.
A solution containing many copies of a bacterial plasmid (circular DNA) is divi
ded equally between four test
tubes. Each test tube is then treated with one of the four enzymes shown. Which enzyme will most likely result in
the highest number of different sized fragments of DNA after treatment?
After the restriction enzymes finish di
gesting the DNA, some of the DNA segment depicted below is added to
each tube. In which test tube will it be possible for this DNA to be joined by the enzyme
to some of
the fragments produced by digestion?
G C T A A G
C G A T T C C T A G
ter the restriction enzymes finish digesting the DNA, a solution containing short segments of RNA with the
U U U C G A
is added to each test tube. In the tube with which enzyme will this RNA be
able to bind to the DNA?
Why is the
e chain reaction (PCR)
used by molecular biologists?
used to make many copies of a specific DNA sequence, very quickly
used to make DNA polymerase enzymes for use in gel electrophoresis
breaks down DNA in the nucleus, producing free nucleotides for DNA rep
cuts up DNA molecules into pieces small enough to be studied more carefully
Which statement about
they are enzymes produced by bacteria for making copies of their DNA
they are enzymes produced by bacteria for making
RNA copies of their DNA
each binds to a specific sequence of DNA and cuts the sugar
phosphate backbones at that site
each binds only to the ends of a DNA molecule, and cuts off several nucleotides from one strand,
producing “sticky end” on both sides.
ich correctly describes the function of the enzyme
makes individual D
hydrogen bonds between DNA nucleotides and free nucleotides in solution
forms covalent bonds between adjacent nucleotides in a growing strand of DNA
unzips” DNA, then forms covalent bonds between adjacent RNA nucleotides
refer to diagrams
showing the control of the
When there is no lactose, what prevents
from producing lactose
the lactose is a structural part of the enzymes
if there is no lactose, the cell doesn’t want to produce the enzymes
when lactose is absent, a protein binds to the bacterium’s DNA and blocks transcription
when lactose is absent, the cell lacks
the energy needed to perform transcription and translation
What is the role of the
promoter that is associated with any gene or group of genes
it is a specific sequence of DNA bases to which RNA polymerase binds whenever transcription occurs
it is a prot
ein that carries RNA polymerase enzymes to the genes that are being activated
it prevents binding regulatory proteins that would block transcription
it binds activator proteins that stimulate transcription
Why is it important for the
to turn on an
d off the enzyme
prevents wasteful production of enzymes
prevents the breakdown of lactose
causes lactose intolerance in humans
prevents lactose intolerance in humans
Free Response Questions
A scientist is interested in a specific gen
e she has found on a large eukaryotic chromosome. She wants to eventually
produce a clone of bacteria with the gene so that the protein
product of the gene can be
Describe how the following techniques might be employed by the resear
cher to establish a colony of bacteria that
possess the gene of interest. (
Cut DNA with restriction enzyme(s)
Perform gel electrophoresis
Use radioactive DNA probe
Use DNA ligase
What is DNA fingerprinting? What genetic engineerin
g techniques are used when DNA fingerprints are made.
Explain why DNA from two different people
, despite the fact that the sequences are more than 99% equivalent,
different DNA fingerprints that could be used to iden
tify the individuals. [4
3. What is the Human Genome Project? How might some of the genetic engineering techniques you’ve learned about
in this unit be applied to help complete the project? How might the information being gained from the project be useful
doctors and other sci
; see pages 249 and p. 267 to learn about the project and its potential benefits]
4. Outline the reasons why increased exposure to UV radiation from sunlight increases a person’s risk of skin cancer.