Assignmenat moudle 5

Biotechnology

The following lesson deals with the issues resulting from our use of biotechnology. While biotechnologies have been used since the brewing of beer by the Sumerians in 1750 BCE, science and technology have created many new possibilities and ethical concerns related to the wide scale use of biotechnologies that involve cloning and gene manipulation. Please read the following introductory material, and then read all of the active links to seven short articles provided at the end of this lesson. Then prepare one dialogue aid sheet for Monday’s class.

What is a cell?

Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. Cells also contain the body’s hereditary material and can make copies of themselves.

Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell.

What is DNA?

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.

DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.

An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.

DNA is a double helix formed by base pairs attached to a sugar-phosphate backbone.

What is Recombinant DNA (rDNA)?

Recombinant DNA (rDNA) is a technology that uses enzymes to cut and paste together DNA

sequences of interest. The recombined DNA sequences can be placed into vehicles called

vectors that ferry the DNA into a suitable host cell where it can be copied or expressed.

Recombinant DNA is therefore artificially constructed by combining genes from different

organisms or by cloning chemically altered DNA for the purpose of genetic manipulation.

Why is rDNA important? Recombinant DNA has been gaining in importance over the last few years, and recombinant DNA will only become more important in the 21st century as genetic diseases become more prevalent and agricultural area is reduced. Below are some of the areas where Recombinant DNA will have an impact.

 Better Crops (drought & heat resistance)  Recombinant Vaccines (i.e. Hepatitis B)  Prevention and cure of sickle cell anemia  Prevention and cure of cystic fibrosis  Production of clotting factors  Production of insulin

 Production of recombinant pharmaceuticals  Plants that produce their own insecticides  Germ line and somatic gene therapy

Stem Cells for Cell-Based Therapies (Lauren Pecorino)

Designer Babies: Ethical Considerations (Nicholas Agar)

Primer on Ethics and Human Cloning (Glenn McGee)

Ethical Issues in Genetic Engineering and Transgenics (Linda MacDonald Glenn)

Genetic Testing to Predict Disease: Ethical, Legal, and Social Implications (ELSI) (Linda

MacDonald Glenn)