1. DNA, Gene Expression,DNA, Gene Expression,
And BiotechnologyAnd Biotechnology
BIOLBIOL 108108
Intro to BioIntro to Bio SciSci
ChapterChapter 55
RobRob SwatskiSwatski
Assoc Prof BiologyAssoc Prof Biology
HACCHACC--YorkYork1
2. Learning GoalsLearning GoalsLearning GoalsLearning Goals
Describe what
DNA is and
what it does.
Explain the
process of
gene
expression
and the
collaboration
of nature and
nurture.
Explain the
causes and
effects of
damage to the
genetic code.
Describe
biotechnology
and its
implications
for human
health.
Discuss
biotechnology
in agriculture.
Discuss
biotechnology
today and
tomorrow.
2
5. What is the most common reason whyWhat is the most common reason why
DNA analyses overturn incorrectDNA analyses overturn incorrect
criminal convictions?criminal convictions?
5
7. Take-Home Message 5.1
DNA is a molecule that all
living organisms carry in
every cell in their body.
DNA is a molecule that all
living organisms carry in
every cell in their body.
Unique in virtually every
person, DNA can serve as an
individual identifier, left
behind us as we go about our
lives.
Unique in virtually every
person, DNA can serve as an
individual identifier, left
behind us as we go about our
lives.
This is a fact that is used
increasingly to ensure
greater justice in our society,
such as through establishing
the innocence of individuals
wrongly convicted of crimes.
This is a fact that is used
increasingly to ensure
greater justice in our society,
such as through establishing
the innocence of individuals
wrongly convicted of crimes.
7
8. 5.2 The DNA molecule contains5.2 The DNA molecule contains
instructions for the developmentinstructions for the development
and functioning of all livingand functioning of all living
organisms.organisms.
8
9. Two Important FeaturesTwo Important Features
of DNAof DNA
DNA contains the
instructions on how to
create a body and control
its growth and
development.
The instructions encoded in
the DNA molecule are
passed down from parent
to offspring.
9
13. Take-Home Message 5.2
DNA is a nucleic acid, a
macromolecule that stores
information.
DNA is a nucleic acid, a
macromolecule that stores
information.
It consists of individual units
called nucleotides: a sugar,
a phosphate group, and a
nitrogen-containing base.
It consists of individual units
called nucleotides: a sugar,
a phosphate group, and a
nitrogen-containing base.
DNA’s structure resembles a
twisted ladder, with the
sugar and phosphate groups
serving as the backbones of
the molecule and base pairs
serving as the rungs.
DNA’s structure resembles a
twisted ladder, with the
sugar and phosphate groups
serving as the backbones of
the molecule and base pairs
serving as the rungs.
13
14. 5.3 Genes are sections of DNA that5.3 Genes are sections of DNA that
contain instructions for makingcontain instructions for making
proteins.proteins.
Why is DNA considered the universal
code for all life on earth?
14
17. Chromosome number varies from
species to species
Corn
10
chromosomes
Fruit flies
4
chromosomes
Dogs &
chickens
39
chromosomes
Goldfish
47
chromosomes
17
18. GenesGenesGenesGenes
A sequence of
bases in a DNA
molecule
Carries the
information
necessary for
producing a
functional
product
…usually a
protein
molecule or
RNA
18
20. Take-Home Message 5.3
DNA is a universal language
that provides the
instructions for building all
the structures of all living
organisms.
DNA is a universal language
that provides the
instructions for building all
the structures of all living
organisms.
The full set of DNA an
organism carries is called its
genome.
The full set of DNA an
organism carries is called its
genome.
In prokaryotes, the DNA
occurs in circular pieces.
In prokaryotes, the DNA
occurs in circular pieces.
In eukaryotes, the genome
is divided among smaller,
linear strands of DNA called
chromosomes.
In eukaryotes, the genome
is divided among smaller,
linear strands of DNA called
chromosomes.
A gene is a sequence of
bases in a DNA molecule
that carries the information
necessary for producing a
functional product, usually a
protein molecule or RNA.
A gene is a sequence of
bases in a DNA molecule
that carries the information
necessary for producing a
functional product, usually a
protein molecule or RNA.
20
21. 5.4 Not all DNA contains
instructions for making proteins.
21
22. An onion has five times as muchAn onion has five times as much
DNA as a human.DNA as a human.
Why doesn’t that make them more
complex than us?
22
26. Take-Home Message 5.4
Only a small fraction of
the DNA in eukaryotic
species codes for
genes.
Only a small fraction of
the DNA in eukaryotic
species codes for
genes.
The function of the
rest is still a mystery,
although it may play a
role in gene regulation.
The function of the
rest is still a mystery,
although it may play a
role in gene regulation.
26
27. 5.5 How do genes work?5.5 How do genes work?
GenotypeGenotype
All of the genes
contained in an
organism
Phenotype
The physical
manifestations of the
instructions
27
29. Take-Home Message 5.5
The genes in strands of
DNA are a storehouse
of information, an
instruction book.
The genes in strands of
DNA are a storehouse
of information, an
instruction book.
The process by which
this information is used
to build an organism
occurs in two main
steps:
The process by which
this information is used
to build an organism
occurs in two main
steps:
…transcription, in
which a copy of the a
gene’s base sequence is
made, and
…transcription, in
which a copy of the a
gene’s base sequence is
made, and
…translation, in which
that copy is used to
direct the production
of a protein.
…translation, in which
that copy is used to
direct the production
of a protein.
29
33. Take-Home Message 5.6
Transcription is the first step
in the two-step process by
which DNA directs the
synthesis of proteins.
Transcription is the first step
in the two-step process by
which DNA directs the
synthesis of proteins.
In transcription, a single copy
of one specific gene within
the DNA is made, in the form
of a molecule of mRNA,
which moves where it can be
translated into a protein.
In transcription, a single copy
of one specific gene within
the DNA is made, in the form
of a molecule of mRNA,
which moves where it can be
translated into a protein.
33
34. 34
5.75.7 In translation, the mRNA copy ofIn translation, the mRNA copy of
the information from DNA is used tothe information from DNA is used to
build functional molecules.build functional molecules.
35. WhatWhat
ingredients areingredients are
needed in theneeded in the
cytoplasm forcytoplasm for
translation totranslation to
occur?occur?
WhatWhat
ingredients areingredients are
needed in theneeded in the
cytoplasm forcytoplasm for
translation totranslation to
occur?occur?
Free amino acids
Ribosomal units
Transfer RNA (tRNA)
35
39. Take-Home Message 5.7
Translation is the second step in
the two-step process by which
DNA directs the synthesis of
proteins.
Translation is the second step in
the two-step process by which
DNA directs the synthesis of
proteins.
In translation, the information
from a gene that has been
carried by the nucleotide
sequence of an mRNA is read,
and ingredients present in the
cell’s cytoplasm are used to
produce a protein.
In translation, the information
from a gene that has been
carried by the nucleotide
sequence of an mRNA is read,
and ingredients present in the
cell’s cytoplasm are used to
produce a protein.
39
41. 5.9 Causes
and effects of
mutation
5.9 Causes
and effects of
mutation
Alteration of the
sequence of bases in
DNA
Can lead to changes in
the structure and
function of the
proteins produced
Can have a range of
effects
41
42. Breast Cancer
in Humans
Breast Cancer
in Humans
Two human genes,
called BRCA1 and
BRCA2
More than 200
different changes in
the DNA sequences of
these genes have
been detected
Each of these changes
results in an increased
risk of developing
breast cancer
42
48. Take-Home Message 5.9
Mutations are alterations in
a single base or changes in
large segments of DNA that
include several genes.
Mutations are alterations in
a single base or changes in
large segments of DNA that
include several genes.
They are rare, but when
they do occur, they may
disrupt normal functioning
of the body (although many
mutations are neutral).
They are rare, but when
they do occur, they may
disrupt normal functioning
of the body (although many
mutations are neutral).
Extremely rarely, mutations
may have a beneficial effect.
Extremely rarely, mutations
may have a beneficial effect.
They play an important role
in evolution.
They play an important role
in evolution.
48
49. 5.10 Faulty
genes, coding for
faulty enzymes,
can lead to
sickness.
5.10 Faulty
genes, coding for
faulty enzymes,
can lead to
sickness.
How can people
respond so differently
to alcohol?
A single difference in
a single pair of bases
in their DNA.
49
51. (1) A mutated gene codes for a non-functioning
protein, usually an enzyme.
(2) The non-functioning enzyme can’t catalyze the
reaction as it normally would, bringing it to a halt.
(3) The molecule with which the enzyme would have
reacted accumulates, like a blocked assembly line.
(4) The accumulating chemical causes sickness and/or
death.
From mutation to illness in just four steps:From mutation to illness in just four steps:
51
52. Take-Home Message 5.10
Most genetic diseases result
from individual mutations that
cause a gene to produce a non-
functioning enzyme, which in
turn blocks the functioning of a
metabolic pathway.
Most genetic diseases result
from individual mutations that
cause a gene to produce a non-
functioning enzyme, which in
turn blocks the functioning of a
metabolic pathway.
52
53. Insert section 5.11-5.13 opener photo
5.11–5.13
Biotechnology is
producing
improvements in
agriculture.
53
54. Genetic Engineering
5.115.11 What is biotechnology?What is biotechnology?
Adding, deleting, or
transplanting genes
from one organism to
another, to alter the
organisms in useful ways
54
56. Biotech advances in humanBiotech advances in human
health fall into three categories:health fall into three categories:
Biotech advances in humanBiotech advances in human
health fall into three categories:health fall into three categories:
Producing
medicines
to treat
diseases
Curing
diseases
Preventing
diseases
from
occurring in
the first
place
56
63. Take-Home Message 5.11
Biotechnology is the use of technology
to modify organisms, cells, and their
molecules to achieve practical
benefits.
Biotechnology is the use of technology
to modify organisms, cells, and their
molecules to achieve practical
benefits.
Modern molecular methods make it
possible to cut and copy DNA from
one organism and deliver it to another.
Modern molecular methods make it
possible to cut and copy DNA from
one organism and deliver it to another.
The methods rely on naturally
occurring restriction enzymes for
cutting DNA, the polymerase chain
reaction for amplifying small amounts
of DNA, inserting the DNA into
bacterial or viral vectors, and cloning
and identifying the cells with the
transferred DNA of interest.
The methods rely on naturally
occurring restriction enzymes for
cutting DNA, the polymerase chain
reaction for amplifying small amounts
of DNA, inserting the DNA into
bacterial or viral vectors, and cloning
and identifying the cells with the
transferred DNA of interest.
63
65. How might a geneticallyHow might a genetically
modified plant help 500 millionmodified plant help 500 million
malnourished people?malnourished people?
Nutrient-rich “golden rice”
65
67. Almost everyone in the United States
consumes genetically modified foods regularly
without knowing it.
67
68. How can genetically modifiedHow can genetically modified
plants lead to reduced pesticideplants lead to reduced pesticide
use by farmers?use by farmers?
68
73. Take-Home Message 5.12
Biotechnology has led to
important improvements in
agriculture by using
transgenic plants and
animals to produce more
nutritious food.
Biotechnology has led to
important improvements in
agriculture by using
transgenic plants and
animals to produce more
nutritious food.
Even more significant is the extent to
which biotechnology has reduced the
environmental and financial costs of
producing food:
Through the creation of herbicide-
resistant and insect-resistant crops
Even more significant is the extent to
which biotechnology has reduced the
environmental and financial costs of
producing food:
Through the creation of herbicide-
resistant and insect-resistant crops
The ecological and health
risks of such widespread use
of transgenic species are
not fully understood and
are potentially great.
The ecological and health
risks of such widespread use
of transgenic species are
not fully understood and
are potentially great.
73
75. Fear #1.Fear #1. Organisms that we want to kill may become
invincible.
Fear #2.Fear #2. Organisms that we don’t want to kill may be
killed inadvertently.
Fear #3.Fear #3. Genetically modified crops are not tested or
regulated adequately. 75
76. Fear #4.Fear #4. Eating genetically modified foods is dangerous.
Fear #5.Fear #5. Loss of genetic diversity among crop plants is
risky.
Fear #6.Fear #6. Hidden costs may reduce the financial
advantages of genetically modified crops.
76
77. Take-Home Message 5.13
More and more genetically
modified foods are being
created using modern
methods of recombinant
DNA technology.
More and more genetically
modified foods are being
created using modern
methods of recombinant
DNA technology.
Some legitimate fears
among the public remain,
however, as to the safety of
these foods given that their
development relies on such
new technology.
Some legitimate fears
among the public remain,
however, as to the safety of
these foods given that their
development relies on such
new technology.
77
79. 5.14 The treatment of diseases and5.14 The treatment of diseases and
production of medicines are improvedproduction of medicines are improved
with biotechnology.with biotechnology.
Preventing diseases
Curing diseases
Treating diseases
• The treatment of diabetes
79
80. Why do some bacteria produce
human insulin?
Recombinant DNA technology
80
81. Several important achievements followed
the development of insulin-producing
bacteria, including:
(1) Human growth
hormone (HGH)
(2) Erythropoietin
81
82. What is “blood doping”?What is “blood doping”?
How does it improve some athletes’
performance?
82
83. Take-Home Message 5.14
Biotechnology has led to some
notable successes in treating
diseases, usually by producing
medicines more efficiently and
more effectively than they can
be produced with traditional
methods.
Biotechnology has led to some
notable successes in treating
diseases, usually by producing
medicines more efficiently and
more effectively than they can
be produced with traditional
methods.
83
84. 5.15 Gene therapy: Biotechnology can5.15 Gene therapy: Biotechnology can
help diagnose and prevent diseaseshelp diagnose and prevent diseases..
But has had a limited success in
curing them
84
85. 1. Is a given set of parents likely to produce1. Is a given set of parents likely to produce
a baby with a genetic disease?a baby with a genetic disease?
Insert figure 5-41
85
86. (2) Will a baby be born with a genetic(2) Will a baby be born with a genetic
disease?disease?
Cystic
fibrosis
Sickle-cell
anemia
Down
syndrome
86
87. (3) Is an individual likely to develop a(3) Is an individual likely to develop a
genetic disease later in life?genetic disease later in life?
Breast
cancer
Prostate
cancer
Skin
cancer
87
89. Why has gene therapy had suchWhy has gene therapy had such
a poor record of success ina poor record of success in
curing diseases?curing diseases?
89
90. (1) Difficulty getting the working gene into
the specific cells where it is needed.
(2) Difficulty getting the working gene into
enough cells and at the right rate to have a
physiological effect.
(3) Problems with the transfer organism
getting into unintended cells.
(4) Difficulty regulating gene expression.
Gene Therapy DifficultiesGene Therapy Difficulties
90
91. Take-Home Message 5.15
Biotechnology allows us to
identify:
Biotechnology allows us to
identify:
…whether a given set of parents
is likely to produce a baby with a
genetic disease,
…whether a given set of parents
is likely to produce a baby with a
genetic disease,
…whether a baby is likely to be
born with a genetic disease,
…whether a baby is likely to be
born with a genetic disease,
…and whether an individual
carriers certain disease-causing
genes that may have their effect
later in life.
…and whether an individual
carriers certain disease-causing
genes that may have their effect
later in life.
These tools can help us to reduce
suffering and the incidence of
diseases, but they also come with
significant potential costs,
particularly the risk of
discrimination.
These tools can help us to reduce
suffering and the incidence of
diseases, but they also come with
significant potential costs,
particularly the risk of
discrimination.
Gene therapy has had a poor
record of success in curing human
diseases, primarily because of
technical difficulties in
transferring normal-functioning
genes into the cells of a person
with a genetic disease.
Gene therapy has had a poor
record of success in curing human
diseases, primarily because of
technical difficulties in
transferring normal-functioning
genes into the cells of a person
with a genetic disease.
91
93. Take-Home Message 5.12
Gene therapy has had a
poor record of success in
curing human diseases.
Gene therapy has had a
poor record of success in
curing human diseases.
This stems primarily from
technical difficulties in
transferring normal-
functioning genes into the
cells of a person with a
genetic disease.
This stems primarily from
technical difficulties in
transferring normal-
functioning genes into the
cells of a person with a
genetic disease.
93
94. Take-Home Message 5.18
Comparisons of sequence
similarities across species
reveal the evolutionary
relatedness and make it
possible to construct
detailed evolutionary trees.
Comparisons of sequence
similarities across species
reveal the evolutionary
relatedness and make it
possible to construct
detailed evolutionary trees.
94
95. 5.16: Cloning5.16: Cloning——
rangingranging fromfrom
genes to organsgenes to organs
to individualsto individuals——
offers bothoffers both
promise andpromise and
perils.perils.
95
97. Are there any medical justificationsAre there any medical justifications
for cloning?for cloning?
97
98. Is it possible to clone aIs it possible to clone a
dinosaur? How coulddinosaur? How could
it be done?it be done?
98
99. Take-Home Message 5.16
Cloning of individuals
has potential benefits in
agriculture and
medicine, but ethical
questions linger.
Cloning of individuals
has potential benefits in
agriculture and
medicine, but ethical
questions linger.
99
100. 5.17 DNA as an individual identifier: the5.17 DNA as an individual identifier: the
uses and abuses of DNA fingerprintinguses and abuses of DNA fingerprinting
100
102. What is a DNAWhat is a DNA
fingerprint?fingerprint?
102
103. Take-Home Message 5.17
Comparisons of highly
variable DNA regions have
forensic value in identifying
tissue specimens and
determining the individual
from whom they came.
Comparisons of highly
variable DNA regions have
forensic value in identifying
tissue specimens and
determining the individual
from whom they came.
103
