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Biotechnology Techniques
Recombinant DNA:
DNA made by connecting DNA from two
different sources.
Example: a human insulin
gene inserted into bacterial
DNA.
Organisms containing
recombinant DNA are called
transgenic.
Producing Recombinant DNA
Utilizes restriction
enzymes:
enzymes that cut
specific sequences of
DNA.
The way that restriction
enzymes cut DNA allows
DNA from 2 different
sources to be joined
together.
Sticky Ends
Many restriction enzymes cut sequence in a
way that produces single-stranded “sticky
ends”.
Any two DNA strands cut with the SAME
restriction enzyme can bind together due
to complementary pairing of sticky ends.
Restriction Enzyme Video: click once on image to start
https://www.youtube.com/watch?v=piGOuud3f40
Complementary
sticky ends
allow the DNA
from 2 different
sources to join
together.
Recombinant DNA video
https://www.youtube.com/watch?v=TpmNfv1jKuA
Pair Share
Discuss with your table partner:
 The definition of recombinant DNA
 How scientist are able to join two pieces
of DNA from different sources together
 Some uses of recombinant DNA
technology
Vectors
Vectors are a means by which foreign
DNA can be transferred into a host cell.
Common vectors:
 Plasmids (small circular secondary
chromosomes from bacteria)
 Viral DNA
Bacterial Transformation
Once a transgenic plasmid is produced, it
can enter a bacterial cell under certain
conditions. This uptake of foreign DNA by
bacteria cells is called transformation.
Plasmid Video:
Click once on image to start video
https://www.youtube.com/watch?v=GNMJBMtKKWU
Conditions for Transformation: Treatment with CaCl2
makes the bacterial cell wall more permeable and help
to allow the uptake of the foreign DNA.
Screening for Successive Transformation
Not all the bacterial cells will successfully take
in the foreign DNA with the desired gene.
In order to be able to screen for successfully
transformed cells, scientists often chose a
plasmid vector with an antibiotic resistance
gene and a host cell that is susceptible to the
antibiotic.
Transformed bacteria cell
with antibiotic resistance
gene on plasmid
Will be able to grow in the
presence of the antibiotic as
well as on regular petri
dishes.
Bacteria cell that did
NOT receive plasmid
Will only be able to grow on
petri dishes that do NOT
contain the antibiotic.
Pair Share
Discuss with your table partner:


The definition of transformation (for
bacteria)
Screening of bacteria for successful
transformation
PCR:
Polymerase Chain Reaction
Magnifies minute quantities of DNA so that
they can be analyzed.



Process:
DNA heated to separate strands (breaks
weaker hydrogen bonds between nitrogen base
pairs).
Single strands incubated with DNA polymerase
and free nucleotides to replicate.
Process repeated multiple times.
Pair Share
Review with your table partner the process
of polymerase chain reaction (PCR)



What is the purpose of PCR
What is the basic process
How does the structure of DNA relate to
how this process works (Hydrogen bonds,
base pairs)