Chapter twenty: Biotechnology

Q1: what's biotechnology?

A1: the manipulation of organisms or their components to make useful products.

Q2: what's recombinant DNA?

A2: DNA molecules formed when segments of DNA from two different sources-often different species-are combined in vitro.

Q3: what's genetic engineering?

A3: the direct manipulation of genes for practical pruposes.

Five Facts:

1. DNA cloning yields multiple copies of a gene or other DNA segment

2. DNA technology allows us to study the sequence, expression, and function of a gene

3. cloning organisms may lead to productino of stem cells for research and other applications

4. the practical applications of DNA technology affect our lives in many ways

5. biotechnology is the manipulation of organisms or their components to make useful products.

Figure:

In presence of polymerase enzyme (heat resistant) separation of a double stranded DNA (parentral strands) by heat at 95 degrees.
o Annealing: Synthetic pair of oligonucleotide probes are allowed to attach to their matcing base sequences on the separated DNA helicals.
o Since DNA polymerase is not denaturated by heat, its presence will allow the small synthesized oligonucleotide probe to extend along the specific DNA fragment – sort of replication-.
o This 3 step cycle is repeated 25 to 35 times.

Summary:

Plasmids are small circular pieces of DNA in bacterial cells that are used to insert pieces of foreign DNA.The DNA is cut using restriction enzymes. The collection of thousands of clones of bacteria containing recombinant plasmids is called a genomic library. Nucleic Acid Hybridizaion is used to detect genes. The DNA of the cell is denatured to produce single stranded DNA. The radioactive probe will hybridize with complementary bases if present. Probes can be radioactive isotopes or flourescent dyes. PCR is used to amplify DNA. Gel electrophoresis is a technique to separate DNA based on the movement of DNA fragments from neg to pos. Smaller fragments travel farther. Samples are placed in gels. Organismal cloning produce genetically identical individuals from a single somatic cell of a multicellular organism. Stem cells are relatively unspecialized cells that continue to reproduce themselves and can be induced to form specialized cells. Therapeutic cloning uses stem cells to replace organs and tissues. Reproductive cloning uses stem cells to reproduce new organisms.

DNA technology identify of human genes in which mutation plays a role in gentic diseases. Single nucleotide polymorphisms(SNPs) are useful genetic markers. When a restriction enzyme is added, SNPs result in DNA fragments with different lengths, or restriction fragment length polymorphisms(RFLP). Gene therapy is the alteration of an afflicted individual's genes. Vectors are used for delivery of genes into specific types of cells.

Video:

http://www.youtube.com/watch?v=mUcE1Y_bOQE