Biotechnology

Biotechnology

Biotechnology is the use of biological processes, organisms,

or systems to manufacture products intended to improve the

quality of human life.

Genetic Engineering- (A.K.A. Recombinant DNA Technology)

frequency of an allele in a population

• *involves cutting (cleaving) DNA from one organism into small fragments & inserting the fragments into a host organism of the same or a different species

• AMAZING!!! Organism will use the foreign DNA as if it were its own!!

• Transgenic Organism- organisms that contain functional recombinant DNA (rDNA) from a different organism

• 4 Areas of Biotechnology

• Agriculture

• Industry

• Forensics

• Medicine

Remember DNA?

• What is the monomer of DNA?– Nucleotides

• How do bases pair? – A – T– C – G

• What kind of bond is used?– Hydrogen bonds between nitrogen bases

I. Restriction Enzymes

• AKA Restriction Endonucleases

• What macromolecule do you think they are made of?– They are PROTEINS that

cut strands of DNA at specific nucleotide sequences

Isolating foreign DNA fragments• -Restriction Enzymes- DNA cutting

enzymes that can cut both strands of a DNA molecule at a specific base pair sequence (A-T, C-G)

• -similar to cutting a zipper into pieces

• -must find the same sequence of base pairs on both DNA strands but they must run in opposite directions

Restriction Enzymes (cont.)

A. There are many different restriction enzymes that each cut DNA at different nucleotide sequences

B. Most will cut the DNA with a staggered cut

C. Usually occurs at a palindrome: a sequence of units that can be read the same way in either direction (ex. Mom, dad, racecar)

5‘…GAATTC…3’ 3‘…CTTAAG…5’

Action of Restriction Enzymes

D. Sticky Ends

1. The staggered cuts leave the DNA with end pieces “sticking off” a. We call these “sticky ends”

b. These exposed N-bases will want to join with other complimentary exposed bases

E. Types of Restriction Enzymes1. Sticky End- already discussed

2. Blunt End a. These cut the DNA straight across and

create blunt ends:

CCC GGGGGG CCC

F. Products generated by restriction F. Products generated by restriction enzymesenzymes1. COHESIVE END CUTTERS (staggered cuts): Enzyme Recognition Site Ends of DNA After Cut

2. BLUNT END CUTTERS (direct cuts): Enzyme Recognition Site Ends of DNA After Cut

5’…GAATTC…3’3’…CTTAAG…5’

5’…G AATTC…3’3’…CTTAA G…5’

EcoRI

Pst I 5’…CTGCAG…3’3’…GACGTC…5’

5’…CTGCA G…3’3’…G ACGTC…5’

HaeIII 5’…GGCC…3’3’…CCGG…5’

5’…GG CC…3’3’…CC GG…5’

1. Restriction enzymes are named according to the following nomenclature:

Ex: EcoRI

• E = genus Escherichia

• co = species coli

• R = strain RY13

• I = first enzyme isolated

G. Restriction Enzyme NamingG. Restriction Enzyme Naming

How is a transgenic organism formed??

• Isolate foreign DNA fragment

• Attach DNA fragment to a “vehicle” (vector)

• Transfer “vehicle” (vector) into a host organism

Forming transgenic organisms and therefore clones of genes

Why would anyone go through the trouble of cutting DNA???

• One reason…– Recombinant DNA

• Break down the word…what do you think recombinant means?

• Other reasons…– DNA fingerprinting, gene therapy…

II. Recombinant DNA

A. Recombinant DNA: DNA that has been cut from one strand of DNA and then inserted into the gap of another piece of DNA that has been broken.

1. The host DNA is often a bacterial cell such as E coli.

B. Bacterial Structure

1. Bacteria are often used in biotechnology because they have plasmids

2. A PLASMID is a circular piece of DNA that exists apart from the chromosome and replicates independently of it.

3. A plasmid is therefore called a VECTOR.

Vectors transfer DNA

• Vector-means by which DNA from another species can be carried into the host cell

• Mechanical Vectors

• Micropipette-inserts into a cell

• Gene guns- tiny metal bullet is coated with DNA and shot into the cell with a gene gun

More types of Vectors• Biological Vectors• Viruses• Plasmids-small ring of DNA found in bacteria

cells that is separate from the bacteria’s normal set of DNA

• Plasmid usually contains genes that may cause the bacteria to be resistant to certain antibiotics

D. Isolating Genes

1. Must isolate the gene of interest first before you insert it into the plasmid

2. How do you do this?a. Use a restriction

enzyme!!!

Final Steps of Making Recombinant DNA1. Once the gene is isolated, have to cut the organism’s DNA

with the same restriction enzyme…why?a. The sticky ends will naturally be attracted to each other

2. Add DNA LIGASE: enzyme that seals the fragments together

3. After the foreign DNA has been spliced (glued) into the plasmid using an enzyme DNA ligase, the rDNA is transferred into a bacterial cell or other organism

4. Now organism is called a Transgenic Organism- organisms that contain functional recombinant DNA (rDNA) from a different organism

Gene Splicing/Cloning using a bacterial plasmid

• -IMPORTANT plasmid replicates separately from the bacterial chromosome & can produce up to 500 copies per bacterial cell

• -bacteria reproduce quickly (20 min) so a lot of rDNA is made very fast

• You will essentially be cloning a gene- genetically identical copies of rDNA molecules

• -Host cell produces the protein coded for by the rDNA

III. Uses for Recombinant DNAA. Recombinant DNA has been gaining importance over the last

few years, and will become more important as genetic diseases become more prevalent and agricultural area is reduced. Below are some of the areas where Recombinant DNA will have an impact:

1. Better Crops (drought & heat resistance) 2. GMO’s (crops like seedless watermelon, pluots, etc.)3. Recombinant Vaccines (i.e. Hepatitis B) 4. Production of clotting factors 5. Production of insulin 6. Production of recombinant pharmaceuticals 7. Plants that produce their own insecticides 8. Germ line and somatic gene therapy

RECAP

• Steps for making a transgenic organism:

1. Locate and isolate the gene of interest

2. Cut out the gene and cut the plasmid using the appropriate restriction enzyme

3. Insert the desired gene into the plasmid matching up the sticky ends

4. Use the enzyme DNA ligase to seal up the sticky ends

5. Transfer the vector in the host organism where it will replicate

6. Host organism produces the protein coded for by the recombinant DNA

Insulin Production

Cloning a gene

Transgenic Animals

Cloning an animal

Plants have been genetically modified to produce insect toxin