13–2manipulating dna a.the tools of molecular biology 1.dna extraction homogenization: cell walls,...

13–2 Manipulating DNA

A. The Tools of Molecular Biology1. DNA Extraction

Homogenization: Cell walls, membranes, and nuclear material are broken

Emulsification: Soap and enzymes break down membranes and emulsify lipids and proteins.

Precipitation: Alcohol is layered on top of the solution. DNA is not soluble in alcohol and precipitates either in the alcohol or at the interface between the alcohol and the rest of the mixture.

Collection: DNA can be pulled up from the interface or alcohol with a paper clip or glass rod.


2. Cutting DNA

“Restriction Enzymes”

Cut DNA at precise locations,

Cut a specific sequence of nucleotides


2. Cutting DNA “Restriction Enzymes”

Cut DNA at precise locations, Cut a specific sequence of nucleotides

Recognition sequences

DNA sequence

Restriction enzyme EcoRI cuts the DNA into fragments. Sticky end


3. Separating DNA

DNA plus restriction enzyme

Mixture of DNA fragments

Gel

Electrophoresis

Power source

Longer fragments

Shorter

fragments


B. Using the DNA Sequence

1. Reading the Sequence

2. Cutting and Pasting

3. Making Copies





3. Making CopiesFluorescent dye

Single strand of DNA

Strand broken after A

Strand broken after C

Strand broken after G

Strand broken after T

Power source

Gel

p324





3. Making Copies

p325

DNA polymerase adds complementary strand

DNA heated to separate strands

DNA fragment to be copied

PCRcycles 1

DNAcopies 1

2

2

3

4

4

8

5 etc.

16 etc.

13–3 Cell TransformationSneaking InYou probably have heard of computer

viruses. Once inside a computer, these programs follow their original instructions and override instructions already in the host computer. Scientists use small “packages” of DNA to sneak a new gene into a cell, much as a computer virus sneaks into a computer.

13–3 Cell TransformationSneaking In1. Computer viruses enter a computer attached to some other file. What are some ways that a file can be added to a computer’s memory?2. Why would a person download a virus program?3. If scientists want to get some DNA into a cell, such as a bacterial cell, to what sort of molecule might they attach the DNA?

CELL TRANSFORMATIONEssential Questions•What happens during cell transformation?•How can you tell if a transformation experiment has been successful?In 13.2 we talked about manipulating DNAHow do we get it back into the cell?TRANSFORMATION- a cell takes in DNA from outside the cell.The DNA becomes part of the cell’s DNAREMEMBER - Griffith’s experiment

TRANSFORMING BACTERIAIn 13.2 we talked about manipulating DNA.How do we get it back into the cell?

TRANSFORMATION- a cell takes in DNA from outside the cell.That DNA becomes part of the cell’s DNAREMEMBER - Griffith’s experiment

Transforming BacteriaForeign DNA attached to plasmidPlasmid - small circular piece of natural DNA

•ensures DNA will be replicated•contains genetic marker

such as resistance to antibiotic(cells that survive antibiotic

have been transformed)

Transforming Bacteria

Plasmid - circular piece of bacterial DNA

Recombinant DNA just has to be inserted into plasmid

Transforming BacteriaBacterial Transformation

Recombinant

Plasmid

Restriction Enzymes: Proteins that cut the DNA in a specific place

Bacterial Transformation

Human Cell

Gene for human growth hormone

Recombinant DNA


Sticky ends

Plasmid

Bacterial chromosome

Section 13-3

Go to Section:


Human Cell


Recombinant DNA


Sticky endsDNA insertion

Bacterial Cell

Plasmid

Bacterial chromosome

Bacterial cell for containing gene for human growth hormone

Section 13-3

Go to Section:


Transforming BacteriaForeign DNA attached to plasmidPlasmid - small circular piece of natural DNA•ensures DNA will be replicated •contains genetic markersuch as resistance to antibiotic (cells that survive antibiotic

have been transformed)

Transforming Plant CellsIn nature, bacteria insert plasmids into

plant cells and produce tumorsResearchers disable tumor producing gene

and introduce foreign DNA Bacteria insert the foreign DNA into the plant

Transforming Plant CellsIn nature bacteria insert plasmid into plant cells that produces tumorsResearchers disable tumor producing gene

and introduce foreign DNA Bacteria insert the foreign DNA into the plant

Sometimes possible to remove cell walland have plants take up DNA on their own

If transformation is successful, the foreign DNA is integrated into one of the host’s chromosomes.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

If transformation is successful, the foreign DNA is integrated into one of the host’s chromosomes.Transforming Animal CellsSimilar to plantsSometimes possible to inject DNA into egg cellsUsually contain marker geneRecently developed techniques enable genes to, “knock out” host gene

Transforming Animal CellsSimilar to plantsSometimes possible to inject DNA into egg cellsUsually contain marker geneRecently developed techniques enable genes to, “knock out” host gene



13.4 Applications of Genetic Engineering•What are some examples of useful transgenic organisms?•What are the main steps involved in cloning?

What are some examples of useful transgenic organisms?What are the main steps involved in cloning?Applications of Genetic EngineeringIn 13.2, we learned how DNA is manipulatedIn 13.3, we learned how foreign DNA is inserted into host cellsDoes this work between animals and plants?

In 13.2, we learned how DNA is manipulatedIn 13.3 we learned how foreign DNA is inserted into host cells

Does this work between animals and plants?

Transgenic OrganismsContain genes from other organismsSpurred growth of BiotechnologyTransgenic MicroorganismsImportant products

•insulin •growth hormoneHuman genes inserted into bacteria

Transgenic MicroorganismsImportant products

•insulin •growth hormoneHuman genes inserted into bacteriaTransgenic AnimalsMice given human genes to study human immune systemLivestock given genes for extra growth hormonePoultry given genes to resist infection

Transgenic AnimalsMice given human genes to study human immune systemLivestock given genes for extra growth hormonePoultry given genes to resist infectionTransgenic PlantsImportant part of food production NOW•52% of soybeans •25%of corn in USBuilt-in insecticidesBuilt-in weed controlA strain of rice with added vitamin A



Transgenic Organisms

13–4 Applications of Genetic Engineering

Sometimes DNA directly injected

“Knockout” genes

A donor cell is taken from a sheep’s udder.

Donor Nucleus

These two cells are fused using an electric shock.

Fused Cell

The fused cell begins dividing normally.

EmbryoThe embryo is placed in the uterus of a foster mother.

Foster Mother

The embryo develops normally into a lamb—Dolly

Cloned Lamb

Egg Cell

An egg cell is taken from an adult female sheep.

The nucleus of the egg cell is removed.

Go to Section:

13–4 Applications of Genetic Engineering: Cloning

A body cell is taken from a donor animal.

An egg cell is taken from a donor animal.

The fused cell begins dividing, becoming an embryo.

The nucleus is removed from the egg.

The body cell and egg are fused by electric shock.

The embryo is implanted into the uterus of foster mother.

The embryo develops into a cloned animal.

13–4 Video: Clone Age

Copy these questions and use them to guide your note taking during the video

1. What is a clone?2. Give some examples of plants and animals that

have been cloned.3. The video claims that there are human clones

walking among us. Explain how this could be true.

4. Would a cloned human be the same as the human he or she was cloned from? Explain

13–2manipulating dna a.the tools of molecular biology 1.dna extraction homogenization: cell walls,...

Documents

separating dna dna

dna copies

dna restriction enzymes

complementary strand

small packages of dna

copies p325 dna polymerase

separate strands dna

cell walls