Unit #3: Biotechnology Splicing and Dicing: DNA and Genetic Engineering

Topics Covered Basic genetics –DNA, RNA Genetic Engineering GMOs and Food Safety Cloning Fertility Treatments

Biotechnology The use of living organisms or systems to develop products for a specific purpose **The most dramatic and controversial biotechnologies have been developed since James Watson and Francis Crick published the structure of DNA in 1953

Applications of Biotechnology Medicine –Pharmaceuticals Pharmacogenomics –Genetic testing –Gene therapy –Cloning Agriculture –Crop yield –Improved nutrition/taste –Animal biotechnology

DNA: The Molecule of Life DNA stands for Deoxyribonucleic acid –Stores information for structural and functional components of living organisms (proteins) –Genetic information is passed on from one generation to the next through sexual reproduction –All traits passed down from parent to offspring are coded for by DNA

In the nucleus of the cell, DNA isnucleus stored in long strands called CHROMOSOMES CHROMOSOMES -Composed of coiled DNA surrounding large protein molecules called histones

Information in DNA is stored on chromosomes as GENES –Each gene contains important information –Instructions in genes code for different characteristics: eye colour, height, ear shape, length of a dog’s tail, colour of a flower’s petals, etc…

Let’s take a look at some traits that we get based on the code of our genes…

Earlobes: Earlobes: Free ear lobes (dominant trait) vs Attached ear lobes (recessive trait) Free earlobes are those that hang below the point of attachment to the head. Attached ear lobes are attached directly to the side of the head.

Widow’s peak: Widow’s peak: Widow’s peak (dominant trait) vs No widow’s peak (recessive trait)

Dimples: Dimples: Dimples (dominant trait) vs No dimples (recessive trait) Dimples are natural dents in the face to the right or left of the mouth. If a person has only one dimple, they should be counted as having dimples. Cleft chin is dominant over no cleft.

Thumbs: Thumbs: Straight thumb (dominant trait) vs Curved thumb (recessive trait) When viewed from the side, curved thumbs can be seen as part of a circle

Pinky: Pinky: Straight pinky (recessive trait) vs Bent pinky (dominant trait)

Mid-digit hair: Mid-digit hair: Mid-digit hair (dominant trait) vs No mid-digit hair (recessive trait)

Longer 2 nd Toe: Longer 2 nd Toe: Longer 2 nd toe is dominant vs 2 nd toe shorter than big toe

Tongue-Rolling: Tongue-Rolling: Rolling up edges (dominant trait) vs Not rolling (recessive)

The Genetic Code DNA is a double stranded molecule, made of a string of building blocks called: NUCLEOTIDES –each nucleotide is made up of 3 parts: Nitrogen bases are like “rungs” of a ladder Sugar- phosphates are the backbones

–Nucleotides bond together into a ladder shape called a DOUBLE HELIXDOUBLE HELIX –There are 4 different nitrogen bases: Adenine (A) Thymine (T) Cytosine (C) Guanine (G) A always binds to T C always binds to G **It is the order of the 4 bases that determines the genetic code! There are MANY possibilities! Think about hair colour… Everyone has a gene for hair colour, but it’s the order of the 4 base pairs in the gene that determines whether you will have brown hair or blond hair!

Cells use the genetic information in DNA to produce proteins Proteins give rise to inherited genetic characteristics The portion of the DNA molecule that controls the production of a particular protein is called a gene **A single molecule of DNA contains many genes