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Unit 4 Part 2: DNA Technology

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Warmup

  1. What type of mutation is typically more damaging? Frameshift mutation or Point mutation?
  2. Translate this sequence: T A C C G C A T C
  3. An enzyme is what type of organic molecule?
  4. True or False: Everyone’s DNA is identical.

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Gel Electrophoresis and DNA Fingerprinting

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Gel Electrophoresis

Gel Electrophoresis: process used to separate DNA fragments by their size.

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Restriction Enzymes

Restriction Enzymes: enzymes (a type of protein) that cleaves (cuts) the DNA into different sized fragments.

  • Different restriction enzymes cut DNA in different places and create different sized fragments.

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Gel Electrophoresis Chamber

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Steps of Gel Electrophoresis

  1. A DNA sequence is cut into different sized fragments by restriction enzymes.

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Steps of Gel Electrophoresis

2. The DNA fragments are

“loaded” into one end of the

gel electrophoresis chamber.

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Steps of Gel Electrophoresis

3. Electricity is used to

move the DNA

fragments from one end

of the chamber to

the other.

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Steps of Gel Electrophoresis

3. Note: smaller DNA

fragments move faster

and travel farther than

larger ones

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* DNA is negatively

charged so it moves

toward the positive (+)

charge on the box

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Steps of Gel Electrophoresis

4. The gel is stained to see

the size of the different

DNA fragments.

Video!

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Purpose of Gel Electrophoresis

Isolate a DNA fragment to be used in recombinant DNA application.

(We’ll talk about this tomorrow!)

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Purpose of Gel Electrophoresis

Compare DNA sequences to identify suspects and determine paternity.

(DNA Fingerprinting!)

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Purpose of Gel Electrophoresis

Identify and catalogue endangered species and evolutionary relationships between organisms.

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Practice

Which lane has the longest DNA fragment?

Which lane has the shortest DNA fragment?

Which lane has a 1500 base pair (bp) DNA fragment?

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Practice

Who is the father of the offspring?

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Practice

Which suspect committed the crime?

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Warmup

  1. What do restriction enzymes do?
  2. Put the steps of Gel Electrophoresis in order
    1. Load DNA fragments into the wells of the gel
    2. Use restriction enzymes to cut DNA
    3. Electricity causes DNA fragments to move through the gel

3-5. Practice EOC Questions

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Recombinant DNA

and Bacterial Transformation

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DNA Cloning

Scientists use DNA cloning to produce multiple identical copies of a DNA fragment.

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DNA Cloning

These DNA fragments are used to produce proteins through the process of protein synthesis.

Review of protein synthesis:

DNA → RNA → protein

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Bacterial Plasmids

Bacterial Plasmid: circular piece of bacterial DNA.

They are able to copy themselves separately from other bacterial DNA.

They can “carry” isolated genes from donor DNA and produce the proteins.

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Restriction Enzymes

Restriction Enzymes: enzymes that can cut DNA to isolate a gene of interest.

There are hundreds of restriction enzymes but each one only recognizes and cuts ONE DNA sequence.

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Process of Bacterial Transformation

  1. A restriction enzyme cuts the plasmid. This creates an area where the target gene (DNA) can bind to the plasmid.

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Process of Bacterial Transformation

2. Restriction enzymes cut the target gene out of the

donor cell.

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Process of Bacterial Transformation

3. The isolated (target) gene and plasmid are linked

together (combined) by an enzyme called ligase.

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Process of Bacterial Transformation

4. The recombinant DNA

plasmid is formed! It is a single DNA molecule combined from two different sources of DNA.

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Process of Bacterial Transformation

5. Recombinant DNA is

inserted into a bacteria cell where it is replicated.

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Process of Bacterial Transformation

6. Scientists select (choose) the bacteria that “carry”

the recombinant plasmids.

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Process of Bacterial Transformation

7. The selected bacteria produce the protein from the

recombinant gene of interest through the process of protein synthesis.

Video!

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Example of Recombinant DNA

Human Insulin:

Insulin is a type of protein.

People with diabetes do not make their own insulin, so they have to use insulin made with recombinant DNA technology.

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Warmup Wednesday 3/20

  1. What do restriction enzymes do?
  2. Put the steps of Gel Electrophoresis in order
    1. Load DNA fragments into the wells of the gel
    2. Use restriction enzymes to cut DNA
    3. Electricity causes DNA fragments to move through the gel
  3. What types of cells are plasmids found in?
  4. Have you heard of GMOs? If so do you think they’re good or bad? Why?

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Genetically Modified Organisms (GMOs)

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Genetic Engineering

Genetic Engineering: when the genetic makeup of an organism is altered (changed) by inserting, deleting, or changing specific pieces of DNA.

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Genetically Modified Organisms

Genetically Modified Organisms (GMOs): organisms that have their genetic makeup altered.

DNA is altered to change a characteristic of the organism.

Examples: corn, soybeans, and cotton

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Video!

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Where does the DNA come from?

  1. DNA from another organism of the same species
  2. DNA from another organism from a different species
  3. DNA that is artificially produced in a lab

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Why make GMOs?

  • Natural pesticide: insert a gene that kills insects when they eat the crop
  • Natural herbicide: insert a gene resistant to the herbicide (so ONLY unwanted plants are killed)

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Why make GMOs?

  • Make crops more disease resistant
  • Improve nutrition of crops by increasing the protein content and the amounts of vitamins and minerals

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Benefits of GMOs

  • Crops grow faster so you can produce more crops in a shorter timespan
  • Crops are more resistant to disease
  • Crops can grow in regions otherwise unsuitable for agriculture

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Benefits of GMOs

  • The environment is harmed less because fewer chemical pesticides and fertilizers are used
  • New crop varieties can be produced

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Issues/ Concerns w/ GMOs

  • Insects develop resistance to chemicals
  • Long term effects on the environment: new crops can out-compete or prey on native ones, and harmful toxins can build up
  • Long term effects on human health: decreased nutritional content of crops and the development of new food allergies

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Examples of GMOs

Roundup Ready Crops

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Examples of GMOs

Golden Rice

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How to Make a GMO

Simulation

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