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Chapter 12
DNA
Do now:
• What are the building blocks of:
•
•
•
•
Carbohydrate=
Proteins=
Lipids=
NUCLEIC ACIDS=
Do now:
• What are the building blocks of:
• Carbohydrate= Monosaccharides
(glucose)
• Proteins= Amino Acids
• Lipids= Glycerol + 3 Fatty Acids
• NUCLEIC ACIDS= Nucleotides
Remember: genes on
chromosomes are inside the
nucleus.
Section Outline
•
12–1 DNA
A.Griffith and Transformation
1. Griffith’s Experiments
2. Transformation
B.Avery and DNA
C.
The Hershey-Chase
Experiment
1. Bacteriophages
2. Radioactive Markers
D.
The Components and
Structure of DNA
1. Chargaff’s Rules
2. X-Ray Evidence
3. The Double Helix
I. Major DNA Experiment
• Griffith’s Experiment
• Avery
• Hershey and Chase
• Wilkins vs. Franklin
• Watson + Crick
• Chargaff
Write one sentence describing what each of these scientists
contributed to the discovery of DNA
Avery
Griffith’s Experiment
Hershey and Chase
DNA
Chargaff
Watson + Crick
Franklin
Frederick Griffith’s
Experiment
• 1928, Tried to find a vaccine against
pneumonia.
• Caused by a pneumococcus bacteria
• Two types of bacteria:
– Type S or smooth covered capsule,
• causes pneumonia
– Type R or rough covered capsule
• Does not cause pneumonia
Video 1
Griffith’s Experiment
• Click the image to play the video
segment.
Griffith’s Experiment
Section 12-1
Heat-killed,
disease-causing
bacteria (smooth
colonies)
Disease-causing
bacteria (smooth
colonies)
Harmless bacteria Heat-killed, disease(rough colonies) causing bacteria
(smooth colonies)
Dies of pneumonia
Lives
Lives
Control
(no growth)
Harmless bacteria
(rough colonies)
Dies of pneumonia
Live, disease-causing
bacteria (smooth colonies)
Type-S
bacteria
Type-R
bacteria
First Step
Heated
Type-S
bacteria
Type-S
bacteria
Type-R
bacteria
Heated
Type-S
bacteria
Second Step
Type-S
bacteria
Type-R
bacteria
Heated
Type-S
bacteria
Third Step
Type-S
bacteria
Type-R
bacteria
Heated
Type-S
bacteria
Fourth
Step
Fred Griffith's Experiments in
Bacterial Transformation
1928
Conclusion:
• Somehow the heated-killed bacteria
had passed their disease-causing
ability to the harmless strain.
Avery and DNA
• Physically and chemically treated
• (broke down) the DNA
• And other scientists discovered that
the nucleic acid DNA stores and
transmits the genetic information
from one generation of an organism
to the next
So then what is a Bacterial
Transformation?
• To introduce a foreign plasmid (ring of
DNA) into a bacteria and to use that
bacteria to amplify the plasmid in order
to make large quantities of it.
• In English, the plasmid takes control
over the bacteria changing the
purpose/function of that bacteria
Hershey and Chase
Blender Experiment
• 1952
• Worked with Bacteriophage
• Used Radioactive Sulfur to tag protein coat.
• Used Radioactive Phosphorus to tag genetic
elements (DNA).
• Use blender
Conclusion: The active component of the
bacteriophage that transmits the infective
characteristic is the DNA. There is a clear
correlation between DNA and genetic
information.
Hershey-Chase Experiment
Section 12-1
Bacteriophage with
phosphorus-32 in
DNA
Phage infects
bacterium
Radioactivity inside
bacterium
Bacteriophage with
sulfur-35 in protein
coat
Phage infects
bacterium
No radioactivity inside
bacterium
Hershey-Chase Experiment
Section 12-1
Bacteriophage with
phosphorus-32 in
DNA
Phage infects
bacterium
Radioactivity inside
bacterium
Bacteriophage with
sulfur-35 in protein
coat
Phage infects
bacterium
No radioactivity inside
bacterium
Figure 12–4 Hershey-Chase
Experiment
Section 12-1
Bacteriophage with
phosphorus-32 in
DNA
Phage infects
bacterium
Radioactivity inside
bacterium
Bacteriophage with
sulfur-35 in protein
coat
Phage infects
bacterium
No radioactivity inside
bacterium
Hershey Chase Experiment
DNA Facts:
1.
It is Transmittable
2.
MADE OF NUCLEOTIDES
3.
A very large molecule consisting of thousands of smaller,
repeating units known as nucleotides. (polymer)
4.
DNA is found in the nucleus of the cell
5.
In recent years, biochemists have found that the DNA of
chromosomes is the genetic material that is passed form
generation to generation
6.
Genes- are sections of DNA molecules
DNA Nucleotide
DNA Nucleotide
Phosphate group
deoxyribose
Nitrogen base
DNA Nucleotide
1. The Basic building block of DNA and RNA
2. 5 types all named because pf their nitrogen base.
adenine, thymine, guanine, cytosine Uracil
3. A DNA nucleotide is composed of three parts:
1. A phosphate group
2. A deoxyribose (5-carbon sugar) molecule
3. A nitrogenous base of either
adenine, thymine,
guanine, cytosine
Uracil
Four DNA Nucleotides
RNA
Only
DNA Nucleotides
Purines
Adenine
Guanine
Phosphate
group
Pyrimidines
Cytosine
Thymine
Deoxyribose
Structure of DNA
Nucleotide
Hydrogen
bonds
Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
The DNA Soap Opera”
by Watson, Crick,
Wilkins and Franklyn
1952: Kings College
X-ray crystallography
Died 1958
Watson-Crick Model
• Watson and Crick developed a model of
the DNA molecule
• In this model, the DNA molecule
consists of two complimentary chains
of nucleotides in a “ladder” type
organization
• Won the 1962 noble prize in science
for their discovery” the double helix”
What does the data tell you???
Source of DNA
A
T
G
C
Streptococcus
29.8
31.6
20.5
18.0
Yeast
31.3
32.9
18.7
17.1
Herring
27.8
27.5
22.2
22.6
Human
30.9
29.4
19.9
19.8
Percentage of Bases in
Four Organisms
Chargaff’s Rule
He observed that there was a
distinct ration between which
nitrogen bases ?
BASE
PAIRING
A=T
C=G
Do Now:
Can you figure out the order of
the nitrogen bases?
Can you figure out the order of
the nitrogen bases?
Double-helix Structure of
DNA
• Each “step” of the
ladder consists of
nitrogenous bases
bonded together by
weak hydrogen bonds
• The two chains of the
DNA molecule are
twisted to form a
spiral, or double-helix
Watson-Crick Model
• The four nitrogenous bases
of the DNA molecule bond
together in only one way:
adenine (A)
thymine (T)
cytosine (C)
guanine (G)
DNA - A More Detailed
Description
A Perfect Copy
• When a cell divides, each daughter cell
receives a complete set of chromosomes
• This means that each new cell has a
complete set of the DNA code. Before a
cell can divide, the DNA must be copied s
that there are two sets ready to be
distributed to the new cells.
Interest Grabber continued
1. On a sheet of paper, draw a curving or zig-zagging
line that divides the paper into two halves. Vary the
bends in the line as you draw it. Without tracing,
copy the line on a second sheet of paper.
2. Hold the papers side by side, and compare the
lines. Do they look the same?
3. Now, stack the papers, one on top of the other, and
hold the papers up to the light. Are the lines the
same?
4. How could you use the original paper to draw exact
copies of the line without tracing it?
5. Why is it important that the copies of DNA that are
given to new daughter cells be exact copies of the
original?
Section Outline
12–2 Chromosomes and
DNA Replication
A. DNA and Chromosomes
1. DNA Length
2. Chromosome Structure
B. DNA Replication
1. Duplicating DNA
2. How Replication Occurs
Structure of DNA
If unwound and
tied together, your
strands of DNA
would stretch 5feet
long and would be
only 50 trillionths
of an inch wide.
The human genome
contains 3 billion
base pairs.
DNA Replication
DNA replication:
1. Double stranded DNA unwinds/
unzips along weak H bonds.
2. Free nucleotides within the nucleus
and incorporated by each unwound
strand.
3. This forms an identical copy.
( replication)
4. New copies in black, but
identical!!!!!
DNA Replication
Copy down this sequence:
pg229
ATCTGAC-
Video 2
DNA Replication
• Click the image to play the video
segment.
Chromosome Structure
of Eukaryotes
Chromosome
Nucleosome
DNA
double
helix
Coils
Supercoils
Histones
Prokaryotic Chromosome
Structure (plasmid)
Chromosome
E. coli bacterium
Bases on the chromosome
DNA Replication
New strand
Original
strand
DNA
polymerase
Growth
DNA
polymerase
Growth
Replication
fork
Replication
fork
New strand
Original
strand
Nitrogenous
bases
Section Outline
•
12–3 RNA and
Protein
Synthesis
A. The Structure of RNA
B. Types of RNA
C. Transcription
D. RNA Editing
E. The Genetic Code
F. Translation
G.The Roles of RNA
and DNA
H. Genes and Proteins
1. What are the three types
of RNA?
2. Why are proteins
important to the human
body???
Three types of RNA
Messenger RNA (mRNA)- bring DNA message out of
nucleus to ribosomes in the cytoplasm.
Transfer RNA (tRNA)- transports amino acids in the
cytoplasm to the ribosomes.
Ribosomal RNA (rRNA)- make identification code of
each ribosome for specific protein manufacturing.
All of this work is for protein synthesis!!!!!!
Do Now: Compare and
Contrast DNA and RNA
BOTH
DNA
RNA
1.
1.
2.
1.
2.
3.
3.
3.
4.
5.
2.
4.
5.
Do Now: Compare and
Contrast DNA and RNA
DNA
1. Deoxyribose
2. Thymine.
BOTH
*Nucleic
acid
3. Double
stranded
* Genetic
information
4. Nucleus only
*made of
Nucleotides
5. Is the
TEMPLATE
that forms an
mRNA strand
RNA
1. Ribose
2. Uracil
3. Single Stranded
4. Formed in nucleus and moves
into cytoplasm
5. carries information from DNA
in the nucleus to the
cytoplasm and helps in the
protein synthesis demands
of a cell
RNA(Ribonucleic acids)
functions to carry information from
DNA in the nucleus to the cytoplasm
and helps in the protein synthesis
demands of a cell.
RNA
vs.
DNA
1. Ribose instead of Deoxyribose
2. Uracil is substituted for thymine.
3. Single Stranded not double stranded
1. What are the three types
of RNA?
2. Why are proteins
important to the human
body???
RNA(Ribonucleic acids)
functions to carry information from
DNA in the nucleus to the cytoplasm
and helps in the protein synthesis
demands of a cell.
RNA
vs.
DNA
1. Ribose instead of Deoxyribose
2. Uracil is substituted for thymine.
3. Single Stranded not double stranded
Three types of RNA
Messenger RNA (mRNA)- bring DNA message out of
nucleus to ribosomes in the cytoplasm.
Transfer RNA (tRNA)- transports amino acids in the
cytoplasm to the ribosomes.
Ribosomal RNA (rRNA)- make identification code of
each ribosome for specific protein manufacturing.
All of this work is for protein synthesis!!!!!!
Concept Map
RNA
can be
Messenger RNA
also called
Ribosomal RNA
which functions to
mRNA
Carry instructions
also called
which functions to
rRNA
Combine
with proteins
from
to
to make up
DNA
Ribosome
Ribosomes
Transfer RNA
also called
which functions to
tRNA
Bring
amino acids to
ribosome
Genetic Code
• A genetic code contains the
information for the sequence of
amino acids in a particular protein
• This code is present in mRNA
molecules and is three bases long.
This is known as a codon
Ex: UAG - is a codon
Messenger RNA (mRNA)
1. When portions of DNA molecules
unwind and separate, RNA
nucleotides pair with complimentary
bases on the DNA strand. This forms
a mRNA that is complimentary to the
DNA strand
2. The sequence of nucleotides in the
mRNA contain the genetic code
3. The genetic code for each amino acid
is a sequence of three nucleotides
Messenger RNA (mRNA)
1. Example: Here the mRNA is
complimentary to the DNA.
2. The DNA serves as the
original template.
DNA
mRNA
T
A
A
U
C
G
(A:T G:C in RNA use U instead of T)
codes
mRNA
Genetic
Section 12-3
The Genetic Code
Do Now:
• Describe the two steps to polypeptide
synthesis.
Do Now: Answers
• Describe the two steps to polypeptide
synthesis.
• 1. Transcription
• 2. Translation
Replication vs. Protein
synthesis
Animated Translation
Protein Synthesis
Transcription:
•
•
Uses the DNA template to make an
mRNA strand inside the nucleus.
mRNA strand exits the nucleus through
a nuclear pore.
Remember
DNA—RNA
A - U
C - G
G - C
T - A
Protein Synthesis
Step 1: Transcription
Occurs in the __ _____
#1 Is _________ . By
using a ___________it
unzips by breaking the
weak H bonds.
#2. mRNA nucleotides
bond to DNA _________
and form an mRNA chain.
TAC ATT AGC CAT
_ __ ___ ___ ___
-DNA TEMPLATE
-mRNA STRAND
#3. mRNA
leaves nucleus
U
Occurs in the
____________
#5. Ribosome and
rRNA line up with
the first “start”
mRNA codon.
Protein Synthesis
Step 2: Translation:
mRNA_
_____
AUG UAA UCG GUA
_______________
#6. tRNA nucleotide carrying an
amino acid
Ribosome
rRNA
#4. mRNA enters
the cytoplasm
AUG UAA UCG GUA
#7 Specific tRNA
lines up with mRNA
at Ribosome
#8. Amino Acids
bond forming a
polypeptide chain.
(Protein)
Riboso
me
rRNA
AUG UAA UCG GUA
Protein Synthesis
Translation:
1. In the cytoplasm, the mRNA strand
becomes associated with a ribosome
and an rRNA molecule
2. Amino acids in the cytoplasm are
“picked-up” by molecules of transfer
RNA (tRNA)
3. Each codon on the mRNA bonds with a
corresponding anticodon on a tRNA,
which carries a specific amino acid
4. The resulting chain of amino acids is a
polypeptide.
Transcription
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA
polymerase
DNA
RNA
Section 12-3
Translation
Translation (continued)
Section 12-3
Label the following structures…
Do Now
• Identify three ways to separate
materials in a science lab:
Do Now: Answers
• Identify three ways to separate
materials in a science lab:
• Gel electrophoresis
– Not restriction enzymes those are used to cut DNA
• Chromatography
• UltraCentrifuge
Section Outline
12–4 Mutations
a. Gene Chromosome theory
b. Gene Expression
c. Heredity and the Environment
d. Gene Linkage
e. Gene Mutation
•
f.
Deletion, insertion
Chromosome Mutations
•
Downs syndrome,
Gene-Chromosome Theory
• Genes exist in a
linear fashion on
chromosomes
• Two genes
associated with a
specific
characteristic are
known as alleles and
are located on
homologous
chromosomes
Gene-Chromosome Theory
for a typical Teenage boy
Do Now:
Gene Mutations:
Substitution, Insertion, and
Deletion
Deletion
Substitution
Insertion
Gene Expression
• You have at least 2 genes for
every trait.
– Genes that are “on” are expressed
– Genes that are “off” are not
expressed
• Mechanisms that can switch genes
on and off include:
– Intracellular Chemicals
– Enzymes
– The Environment
How old are we?
23, So what’s the difference?
Heredity and the Environment
• The development and expression of
inherited traits can be influenced by
environmental factors such as:
– Nutrients
– **Sunlight**
– **Temperature**
• Normal white with black ears, shave the
back and apply an ice pack: the hair will
grow back BLACK!!!
Gene Linkage
• Genes for different traits are
located on the same chromosome
pair, and are said to be linked
• Therefore they are usually
inherited together
*Red hair and freckles
Human Disorders associated
with Sex-Linked Genes
1. Hemophilia- disease in which the blood
does not clot properly
2. Colorblindness- inability to see certain
colors, most commonly red and green
* Both of these disorders are more common
in males than in females because a
female will not show the disorder as long
as she has one normal gene. Females
who are heterozygous for a sex-linked
trait are said to be carriers for that trait
Mutagenic
Agents
Causes mutations
• Radiation- ultraviolet
light, x-rays, radioactive
substances
• Chemicals- asbestos
fibers
Genetic Mutations
• Changes in genetic material are called
mutations
• If a mutation occurs in the sex cell, it may be
transmitted to the offspring (sperm or egg)
• Mutations in body cells may be passed on to
new cells of the individual due to mitosis,
but will not be transmitted to the offspring
by sexual reproduction,
Ex: cancer
• Mutations can be classified as:
chromosomal alterations or gene mutations
Chromosomal Mutations
Deletion
Duplication
Inversion
Translocation
Chromosomal Alterations
• Changes in the number of chromosomes or
in the structure of the chromosome
• The are often visible in the phenotype of an
organism because many genes are usually
involved.
• An example:
*Translocation: (deletion, inversion, addition)
*Nondisjuction
*Polyploidy
*Changes in the chromosomal structure
Nondisjunction
• One or more pairs of
homologous
chromosomes fails to
separate.
• This results in gametes
with more
• (or less) than their
normal haploid
chromosome number
Nondisjunction
During meiosis
How does nondisjuction affect
a gametes monoploid number?
Normal sperm or egg (n) =23,
Nondisjuction in humans (n)= 22,
24, 25, 45
If these gametes are involved in
fertilization, the resulting
zygote may have more (or
less) than the normal diploid
chromosome number. 2n= 45,
47, 48, 68
Results of Nondisjunction in humans:
1. Down’s Syndrome- extra #21 chromosome.
This is due to the nondisjunction of chromosome #21 in one
of the parents.
2. Kleinfelters Syndrome: Extra X chromosome (X,X,Y)
3. Turners Syndrome: Missing a sex chromosome (X,0)
4. Triploid: having 1 extra of every homologous pair (69)
chromosomes)
5. Polyploidy- sometimes all 22 chromosomal pairs fail to
separate. The resulting 2n gamete fuses with the normal
n gamete, producing a 3n zygote. This is common in
plants but rare in humans
Down Syndrome
Gene Mutations
• Involves a random change in the chemical
nature of the genetic material (DNA)
• Some gene mutations, like albinism are
obvious, while others are not noticeable
• (Several different genes are involved with
pigment production, including genes on
chromosomes 9,10, 11,13,15 and X, but
it's not clear exactly what role each of
these plays in the condition. In most
cases there is no family history and the
children are born to parents with normal
pigmentation for their race.)
N= Normal Pigmentation
n = Albinism recessive
Gene Mutations albinism
About one in every 17,000 people have Albinism.
These individuals fail to produce melanin, a
photoprotective pigment. While melanin's role in
protecting us from ultraviolet light is understood, it
also has other important functions in the
development of the retina and brain and their
interconnection of which we know much less..
Muscular Dystrophy
• Muscular dystrophies are a group of
more than 20 different genetic neuromuscular disorders, some more
debilitating than others.
• They include Congenital Muscular
Dystrophy (CMD), Duchenne
Muscular Dystrophy (DMD), Becker
Muscular Dystrophy (BMD),
Facioscapulohumeral Dystrophy
(FSH) and others.
Most involve mutations in genes
involved in muscle structure and
function - in Duchenne MD for example,
there is a single genetic fault in the
production of a protein in muscle fibres
called dystrophin.
Section Outline
12–5 Gene Regulation
A. Gene Regulation: An
Example
B. Eukaryotic Gene
Regulation
C. Development and
Differentiation
Typical Gene Structure
Section 12-5
Regulatory
sites
Promoter
(RNA polymerase
binding site)
Start transcription
DNA strand
Stop transcription
Video 3
DNA Transcription
• Click the image to play the video
segment.
Video 4
Protein Synthesis
• Click the image to play the video
segment.
Video 5
Duplication and Deletion
• Click the image to play the video
segment.
Video 6
Translocation and Inversion
• Click the image to play the video
segment.
Video 7
Point Mutations
• Click the image to play the video
segment.
Do Now
Finish this statement: The only way Genetic
diseases can be inherited from _________ to
________ is through the DNA codes found
in ______ ________. Two examples are
_____ and _____.
Do Now
Finish this statement: The only way Genetic
Parents
diseases can be inherited from _________
to
Offspring
________ is through the DNA codes found
SEX CELLS
in ______
________. Two examples are
Sperm and _____.
Egg
_____
Malfunctions
And
DNA
Technologies
(V) Human Genetic
Disorders
1. Phenylketonuria
(PKU)
• A disorder in which the body
cannot make an enzyme
necessary for the normal
conversion of phenylalanine
• autosomal recessive disorder,
(caused by mutations in both alleles of the
gene for phenylalanine hydroxylase (PAH),
• found on chromosome 12
• Results in mental retardation
and organ damage
2. Sickle-cell Anemia
• A gene mutation
that results in the
production of
abnormal
hemoglobin
molecules and
abnormal red
blood cells
• Most common in
African Americans
3.
Tay-Sachs
• Deterioration of the nervous
system due to the accumulation
of fatty material as a result of
the inability to synthesize a
specific enzyme
• Jewish people of Central
Europe descent
Tay-Sachs
By about two years of age, most children experience
recurrent seizures and diminishing mental function. The
infant gradually regresses, losing skills one by one, and is
eventually unable to crawl, turn over, sit, or reach out.
Other symptoms include increasing loss of coordination,
progressive inability to swallow and breathing difficulties.
Eventually, the child becomes blind, mentally retarded,
paralyzed, and non-responsive to his or her environment.
(VI) Types of Genetic
Disorder Detection
Techniques
1.
Screening
• Chemical analysis of body
fluids such as blood and
urine
• Detection of PKU and
Tay-Sachs
Replication
Normal somatic cell
2n = 46
Sperm cell
n=23
Amniocentesis
• Fetal cells are
removed and
surveyed for
genetic
disorders
2.
Karyotyping
• The preparation of an
enlarged photograph of
chromosomes
Karyotype animation:
http://gslc.genetics.utah.edu/units/disorders/karyotype/karyotype.cfm
Normal MAle
Normal
feMAle
3.
Amniocentesis
• Removal of amniotic fluid for
chemical and/or cellular
analysis
• Detection of sickle-cell
anemia
4. Remember Sex Linked
Diseases????
•
•
•
•
•
Hemophilia
Colorblindness
Duchene's Muscular Dystrophy
Achondroplasia
4. Remember Sex Linked
Diseases????
• Y is it easier for a male to inherit
an “X” sex linked disease then a
female?
•
Genghis Khan's legacy?
Genes of History's Greatest
Lover?
• According to an international team of
geneticists, about 1 in 12 men in Asia-and therefore 1 in 200 men worldwide-carry a form of the Y chromosome that
originated in Mongolia nearly 1,000 years
ago.
• Of course, this is a guess because we don’t have Genghis
Khan’s DNA. (1162-1227)
• His tomb remains hidden although the search is on to find
it. Once we have his DNA, then we can determine if he
really was as prolific as this data suggests.
Pedigree
• Is a diagram that shows the occurrence
appearance, or PHENOTYPES of a
particular genetic trait.
male
Marriage line
female
children
Pedigree of hemophilia in the
Romanov family
Pedigree of hemophilia in the
Romanov family
Pedigree of hemophilia in the
Romanov family
Anastasia AKA
Anna Anderson or not
???
• Anna Anderson claimed of being the Grand
Duchess Anastasia and that as a child she had
escaped her captors 1n 1919
• Her claims were fought over by the royals of
Europe throughout the 20th century.
• How did they solve this problem???
• Anna Anderson was not related to the
Romanovs. When she died, she was cremated,
but samples of tissue were in possesion of a
hospital where Ms. Anderson was operated on.
Also found were locks of her hair after her
husband, John Manahan passed away. Tests
done comparing the DNA from Anna's tissue to
the Romanov tissue found no match.
Anastasia AKA
Anna Anderson or not
???
• How did they solve this problem???
• As per instructions when she died, she
was cremated, but samples of tissue were
in possession of a hospital where Ms.
Anderson was operated on.
• Also found were locks of her hair after her
husband, John Manahan passed away.
Tests done comparing the DNA from
Anna's tissue to the Romanov tissue
found no match.
• Then who was she??????
Separation Techniques
• Chromatography-to make visible
pigments and extracts
• Centrifuge-separates based on
densities
• Gel Electrophoresis: Separates
into DNA fragments
Gel
Electrophoresis
• is a procedure for separating a
mixture of DNA molecules through
a stationary material (gel) in an
electrical field.
http://learn.genetics.utah.edu/units/biotech/gel/
Gel
Electrophoresis
http://learn.genetics.utah.edu/units/biotech/gel/
Gel
Electrophoresis
1 Gene to 1 Polypeptide Hypothesis
•Each gene directs the synthesis of a
particular polypeptide (protein) chain.
•Genes control the synthesis of
enzymes. SO If we mutate that gene
it will affect the creation of that
enzyme…..
Genetic Engineering
• Now that we understand genes we can
change the DNA of a cell.
• The procedure for producing altered DNA
is called genetic engineering
• Altered DNA is called Recombinant DNA.
• Gene splicing involves the breaking of a
DNA molecule and inserting or attaching
new genes by means of a chemical splice.
Genetic Engineering
Recombinant DNA due to Gene
splicing
• Medical
– Human insulin producing bacteria
– Human Growth Hormone (HGH) producing
bacteria
– Diabetic-donor corrective gene therapy
• Agriculture and Forestry
–
–
–
–
Pest Resistant Crops (corn)
Antibiotic Rich Corn
HGH infused trout (live stock)
Inc Growth rate in trees and insect repellent
trees (logging)
DNA Technology
• Makes it possible to put “new” genes
into organisms.
1. Human genes can be inserted into
bacteria.
2. These altered bacteria become
factories that produce human protein.
ex: Gene Splicing
Recombinant DNA
VI Genetic Engineering
• Genetic Engineering- is a new technology
that humans use to alter the genetic
instructions in organisms.
a) Biotechnology- The application of
technology to biological science.
ex: removal of dinosaur DNA from a
mosquito’s last meal.
b) Selective Breeding- A process that
produces domestic animals and new
varieties of plants with traits that are
particularly desirable.
Selective Breeding
An Example of Selective Breeding
Brahman
cattle:
Good
resistance to
heat but poor
beef.
English
shorthorn
cattle: Good
beef but poor
heat
resistance.
Santa
Gertrudis
cattle:
Formed by
crossing
Brahman and
English
shorthorns;
has good
heat
Recombinant DNA
• Allows scientists to insert the
insulin gene into bacterial
plasmids.
• The bacteria that contain this
gene produce insulin, which is
used by people with diabetes.
What is Gene Splicing?
A dessert?
Gene Splicing
Transgenic mice:
Slicing jellyfish DNA in a
mouse's genome!!!
Genetic Engineering and
Therapies
• Genetic engineering attempts to correct
genetic defects, alter foods , and fight
diseases.
• Gene therapy replaces defective genes
with normal genes.
• Gene splicing using plasmids (ring
shaped sections of bacterial DNA) can
be used to create desirable traits.
Plasmids
• Are small DNA fragments, are
known from almost all
bacterial cells.
• Plasmids carry between 2
and 30 genes. Some seem to
have the ability to move in
and out of the bacterial
chromosome
Superhero Gene Splicing
Foreign
DNA
Gene Splicing
Gene Splicing
plasmids
Biotechnology
Biotechnology
Biotechnology
Each bacterial cell can now make
human insulin
Each bacterial cell has the gene for making human
insulin.
Gene Splicing
Gene Splicing
Gene Splicing
Transgenic mice:
Slicing jellyfish DNA in a
mouse's genome!!!
Gene Splicing
• Allows a scientist to make cuts of DNA from 2
complimentary different organisms, perhaps a frog
cell and a bacterium.
• Pieces of DNA from one organism can now be
glued, or spliced, into the DNA of another
organism.
Plasmids
• Are small DNA fragments, are known from
almost all bacterial cells.
• Plasmids carry between 2 and 30 genes.
Some seem to have the ability to move in
and out of the bacterial chromosome
Cloning from Adult Vertebrate
Cells
Cloning
• A clone is a group of individual
organisms that have exactly the same
genes.
• Organisms that reproduce asexually
produce clones, since each offspring
receives an exact copy of the genes of
the parent.
• Dolly, 276 tries, 277= dolly
Cloning
Cloning
• Is a technique that accomplishes the same end result as
asexual reproduction.
• It is a way of making identical genetic copies.
• Cloning is done by inserting a nucleus from a “parent”
organism’s cell (one that has a complete set of genetic
information from that individual) into an egg cell from which
the nucleus has been removed. The result is an egg that now
contains not 50%, but 100% of the genetic information from a
single parent.
• If this new egg cell with all of its genes can be made to
develop normally, the resulting offspring is a clone of the
individual that donated the original cell (In mammals, the egg
would be implanted and develop inside the body of the
female).
Cloning
Population Genetics
• A population is a group of organisms
of the same species living together in
the same region (interbreeding).
• Population genetics: is the study
of changes in the genetic makeup of
populations.
• Gene Pool: The total of all the
genes in a population at any given
time.
Population Genetics
• Gene frequencies: how often
(frequent) a specific gene shows up in
a population.
Population Genetics
The Hardy Weinberg Law: Under
certain conditions the relative
frequencies of alleles for a given
trait in a population do not change.
For this to be true:
1) The population must be large
2) Individuals must not migrate into or
out of the population.
3) Mutations must not occur
4) Reproduction must be completely
random.