Chapter 15, Problem 11STP

Summary Introduction

To describe:

The process used by scientists to synthesize a specific protein from a particular kind of bacteria.

Introduction:

Researchers use genetic engineering to manipulate DNA. Biotechnology is the science of using genetic engineering to solve problems. It makes possible to produce organisms that contain individual genes from another organism. Such genetically engineered organisms are called transgenic organisms.

Answer to Problem 11STP

Transgenic bacteria can be used to synthesize specific proteins such as insulin and growth hormones.

There are several steps involved in creating such bacteria:

1. Recombinant plasmid DNA- First the genes coding for a specific protein has to be identified in an organism. A recombinant plasmid DNA is formed by cleaving DNA that code for a specific protein from one organism into small fragments and then inserting the fragments into a vector such as a plasmid of a bacterial cell.
2. Transformation- Large quantities of recombinant plasmid DNA has to be made. The recombinant plasmid carrying the foreign DNA is introduced into the host bacterial cell. Such bacteria are called transformed bacteria.
3. Gene cloning- Replication of transformed bacteria produces millions of copies of bacteria called gene clones. Recombinant plasmid replicates independently of the bacterial chromosome. These clones contain the recombinant DNA molecules that can now code for the desired protein.

Explanation of Solution

A transgenic bacterium contains genes from another species. It can be produced by genetic engineering. The process involves cutting or cleaving DNA that code for a specific protein from one organism into small fragments and then inserting the fragments into a host organism of the same species or different species. The host organism uses the foreign DNA as if it were its own.

A carrier known as a vector transfers the recombinant DNA into a bacterial cell called the host cell. Plasmids are commonly used as vectors. Plasmids are small, circular, double stranded DNA molecules that occur naturally in bacteria. They can be used as vectors because they can be easily cut with restriction enzymes. A recombinant plasmid DNA is formed.

To make large quantities of recombinant plasmid DNA, bacterial cells are mixed with recombinant plasmid DNA. Some bacteria take up the recombinant plasmid DNA through a process called transformation. Bacterial cells can be transformed by heating or using electric pulsation. It can now make multiple copies of recombinant plasmid DNA during cell replication.

Millions of identical bacteria are produced each containing the recombinant DNA molecules. This process is called gene cloning.

These clones can be activated to produce specific protein as they contain the genes coding for that protein.