Genetic Engineering 0008D Tony Hoffman

What is Genetics…? What do things look like? and why? Genetics The study of genes and heredity, or how characteristics are passed from parents to children. All Definitions from:

Why do things look the way they do? DNA (deoxyribonucleic acid) - a large double-stranded, spiraling molecule that contains genetic instructions for growth, development and replication. This DNA is a set of instructions that tells cells to form in a particular way. DNA is the reason we have so many different kinds of cells. It is very small and large amounts can be found in each cell.

What is DNA made up of? Bases - the molecular building blocks of DNA: adenine (A), cytosine (C), guanine (G) and thymine (T). In DNA, A attaches only to T, and C attaches only to G. These pairs are called base pairs.

Chromosome - a long coiled strand in the nucleus, made up of DNA and protein. DNA is organized into segments so that it is not one long strand. These segments are called chromosomes. Is DNA a long strand that travels throughout an organism? No.

Gene - the unit of heredity in chromosomes; a segment of double- stranded DNA. Genes are small little individual segments on each chromosome (the colors on the picture). Each of these genes is a different trait that is displayed by the organism that carries it. A chromosome can carry thousands of genes. Chromosomes are broken down further into……

Can we change DNA? Yes we can…by a method called Gene Splicing - the process of cutting the DNA of a gene in order to add base pairs. 1.Chemicals called restriction enzymes act as the scissors to cut the DNA. Once it finds that sequence in a strand of DNA, it attacks it and splits the base pairs apart, leaving single strands at the end of two double strands. 2.Scientists are then free to add any genetic sequences they wish into the broken chain. 3.Afterwards, the chain is repaired (as a longer chain with the added DNA) with another enzyme called ligase.