4.4: Genetic Engineering and Biotechnology

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Oct 22, 2013 (3 years and 11 months ago)

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4.4: Genetic Engineering and Biotechnology
˒
Outline the use of polymerase chain reaction
(PCR) to copy and amplify minute quantities of
DNA.
˒
State that, in gel electrophoresis, fragments
of DNA move in an electric field and are
separated according to their size.
˒
State that gel electrophoresis of DNA is used
in DNA profiling.
4.4: Genetic Engineering and Biotechnology
˒
Describe the application of DNA profiling to
determine paternity and also in forensic
investigations.
˒
Analyze DNA profiles to draw conclusions
about paternity or forensic investigations.
4.4: Genetic Engineering and Biotechnology
˒
Outline 3 outcomes of the sequencing of the
complete human genome.
˒
State that, when genes are transferred
between species, the amino acid sequence of
polypeptides translated from them is
unchanged because the genetic code is
universal.
4.4: Genetic Engineering and Biotechnology
˒
Outline a basic technique used for gene
transfer involving plasmids, a host cell
(bacterium, yeast or other cell), restriction
enzymes (endonucleases) and DNA ligase.
˒
State 2 examples of the current uses of
genetically modified crops or animals.
˒
Discuss the potential benefits and possible
harmful effects of one example of genetic
modification.
4.4: Genetic Engineering and Biotechnology
˒
Define clone.
˒
Outline a technique for cloning using
differentiated animal cells.
˒
Discuss the ethical issues of therapeutic
cloning in humans.

Genetic engineering
and
biotechnology
have opened
up new opportunities in forensic science (you know
this as CSI), agriculture, medicine and food technology.

We are going to discuss in depth how science has
allowed people to change the genetic identity of
organisms - GMO's and Cloning!
4.4: Genetic Engineering and Biotechnology

DNA Profiling:
matching the DNA from a sample to a known
individual.

At a crime scene, forensic scientists check for
fingerprints, collect samples of hair, skin, blood, semen,
and anything else that can be used to identify the
suspect.

DNA profiling, can not only establish if a person is
guilty or innocent, but can be used to determine
paternity because DNA is unique to that individual

Making a DNA profile requires 2 parts:

1. Polymerase Chain Reaction (PCR)

2. Gel Electrophoresis.
4.4: Genetic Engineering and Biotechnology

1. Polymerase Chain Reaction (PCR):
makes millions
of copies of tiny amounts of DNA so there is enough
for a DNA profile.

Sometimes, at a crime scene or when a body is
found after a very long time, only a small amount
of DNA can be collected.

Making a DNA profile on someone only works with
a
significant amount of DNA
.

PCR uses the segment of DNA that needs to be
replicated, as a template, setting in motion a chain
reaction in which the DNA template is
exponentially amplified.
4.4: Genetic Engineering and Biotechnology

Making a lot of DNA is done at a high temperature
using the enzyme
DNA POLYMERASE
.

PCR targets a specific DNA sequence and allows
the enzyme DNA polymerase to assemble a new
DNA strand from DNA building blocks
(nucleotides)

Temperature both heats up and cools down the
strand - allowing strands to separate and re
form as new DNA is made at a rapid pace.

Sum up PCR: to copy and amplify (enlarge)
small quantities of DNA
4.4: Genetic Engineering and Biotechnology
4.4: Genetic Engineering and Biotechnology
PCR

2. Gel Electrophoresis:

method used to separate DNA
fragments based on their size
and electric charge.

After you use PCR to
amplify a small amount of
DNA you found at a crime
scene, how can you tell if
the suspect is guilty who is
the dad of a child?

Run the DNA sample
through a Gel
Electrophoresis!
4.4: Genetic Engineering and Biotechnology
4.4: Genetic Engineering and Biotechnology

Any DNA sample usually contains molecules that are
too long to process to make a DNA profile.

Restriction Enzymes
are used to cut DNA into
fragments at very precise points in the sequence.

Because everyone has a different sequence, an
individual is going to have unique DNA fragments
that are cut.

Thus, each person will have DNA fragments of
different sizes.
4.4: Genetic Engineering and Biotechnology

1. DNA fragments are placed in a well in a plate of gel
(material like jell-o)

2. An electric field is applied.

3. Each DNA fragment has a small negative charge so they
will move through the electric field in the gel to the positive
charge, all the way at the end of the gel.

4. The distance a fragment moves depends on its size.

Smaller fragment = farther distance traveled in gel

Larger fragment = short distance traveled, stay by the
well

5. After fragments have been separated, what is produced
is a unique pattern of bands called a
DNA profile
4.4: Genetic Engineering and Biotechnology
4.4: Genetic Engineering and Biotechnology

In each picture, circle the guilty suspect or
real father!
4.4: Genetic Engineering and Biotechnology

In each picture, circle the guilty suspect or
real father!
4.4: Genetic Engineering and Biotechnology

The Human Genome Project (HGP):


In 1990, an international venture (HGP) set out to
sequence the complete human genome.

20,000-25,000 genes, location of all these
genes on the human chromosomes and the
base sequence of the DNA that makes them up.

A genome is a catalog of all the bases
(A/T/G/C) our chromosomes contain.

The human genome can be thought of as a map to
show the locus of any gene on any one of the 46
chromosomes.
4.4: Genetic Engineering and Biotechnology

The $3 billion project was given 15 years, but it
was completed in 13 - in 2003.

Since then, scientists have completed the genomes
of other organisms, such as E. coli, fruit fly, and
field mouse.
4.4: Genetic Engineering and Biotechnology

Advantages/outcomes of the HGP:

1.
Easier identification of human diseases

As you have seen, some diseases are sex-linked, so
with those diseases it is easy to tell which
chromosome the gene responsible for the disease
is found on - almost always on the X chromosome.

In traits/diseases with no sex linkage, a little bit
trickier.

Now that the HGP completed, doctors can look on
the genome library to find out exactly where to
look if they think one of their patients might have
a disease-carrying allele.
4.4: Genetic Engineering and Biotechnology

2.
Production of new drugs

Scientists can find beneficial proteins which are
produced naturally in healthy people.

Find out which gene controls the production of
those proteins.

Copy that gene and use it as instructions to make
that protein in a lab.

Scientists are working on gene therapy: drugs
that work to repair or replace a faulty gene -
essentially drugs tailored to a specific individual.
4.4: Genetic Engineering and Biotechnology

3.
Insights into the origins, evolution and migrations
of humans.

By comparing the genetic makeup of populations
around the world, countless details could be
revealed about ancestries and how humans have
migrated and mixed their genes with other
populations over time.

Without knowing it, you are carrying around in
each one of your cells a library of information
about your past.
Topic 4: Genetics

30. Which disease is an example of sex-linked (X-
linked) inheritance?

A. AIDS

B. Down syndrome

C. Sickle-cell anemia

D. Hemophilia

Answer: D
Topic 4: Genetics

31. Which process is used in polymerase chain
reaction (PCR)?

A. Transcription

B. Translation

C. Replication

D. Mutation

Answer: C
Topic 4: Genetics

32. How can fragments of DNA be separated?

A. Using polymerase chain reaction (PCR)

B. Using gel electrophoresis

C. Using gene transfer

D. Using gene cloning

Answer: B
Topic 4: Genetics

33. What could be achieved by DNA profiling using gel
electrophoresis?

A. The chromosome number of an organism could be
counted.

B. It could be shown that human tissue found at the site
of a crime did not come from a person suspected of
having committed the crime.

C. A karyotype could be produced.

D. Extinct species of living organisms could be brought
back to life.

Answer: B
Topic 4: Genetics

34. Why can DNA profiling be used to determine
paternity?

A. Genes of children are exactly the same as their
father's

B. Half the genes of children are the same as their
father's

C. The father passes on all of his genes to each of his
children

D. The father passes on a fraction of his genes equal
to the number of his children.

Answer: B
Topic 4: Genetics

35. The diagram below represents the results
obtained in a DNA profile from a crime scene. Suspect
2 is
most
likely to be the criminal because the band
pattern concides with that of the crime scene sample.
What do these bands represent?

A. DNA fragments

B. Genes

C. Chromosomes

D. Chromatids

Answer: A
!
Topic 4: Genetics

36. What conclusion can be made
from the following evidence from
an analysis of DNA fragments?

A. Both children are related to
both parents

B. Child I is related to the man
but child II is not

C. Both children are unrelated to
either of the parents

D. Child II is related to the man
but child I is not

Answer: A
!
Topic 4: Genetics

37. A small amount of a suspect's DNA is obtained
from a crime scene. What techniques would be used to
carry out DNA profiling?

A. Gel electrophoresis and paternity testing

B. Paternity testing and the polymerase chain reaction
(PCR)

C. Polymerase chain reaction (PCR) and gel
electrophoresis

D. Test crossing and pedigree analysis

Answer: C
Topic 4: Genetics

38. The Human Genome Project allowed the first
accurate estimates of the number of different
genes in the human genome. What was a typical
estimate, based on the results of the Human
Genome Project?

A. 46

B. 64

C. 25,000

D. 1,000,000

Answer: C
Topic 4: Genetics

39. How are plasmids used in technology?

A. For respiration in prokaryotes

B. For photosynthesis in eukaryotes

C. For protein synthesis in prokaryotes and
eukaryotes

D. For gene transfer

Answer: D
Topic 4: Genetics

40. What type of enzyme could be used to cut a
DNA molecule as indicated by the dotted line on
the diagram below?

A. DNA ligase

B. DNA polymerase

C. Helicase

D. Restriction enzyme

Answer: D
!
Topic 4: Genetics

41. Which enzymes are needed to incorporate
genes into plasmids to create recombinant
plasmids?

A. DNA polymerase and ligase

B. DNA polymerase and restriction enzymes

C. Restriction enzymes and ligase

D. Helicase and restriction enzymes

Answer: C
Topic 4: Genetics

42. Which enzymes are needed to produce
recombinant plasmids to be used in gene transfer?

A. DNA polymerase and DNA ligase

B. DNA polymerase and restriction enzyme
(endonuclease)

C. Transcriptase and RNA polymerase

D. Restriction enzyme (endonuclease) and DNA
ligase

Answer: D

43. Which
processes
involved in
cloning an
animal are
indicated by the
letters X and Y?

Answer: A
X
Y
A
differentiated cell
removed from animal
nucleus removed from
unfertilized egg cell
B
sex cell removed from
animal
nucleus removed from
differentiated animal cell
C
sex cell removed from
animal
nucleus removed from
unfertilized egg cell
D
differentiated cell
removed from animal
nucleus removed from
differentiated animal cell
!