DNA/GMOs

USDA approved GMOs

Corn, soybeans, cotton, canola, alfalfa, sugar beats, papaya, squash, arctic apples, innate potato, aqua beauty salmon.

Mexico, 7000 BC

Corn cultivation started in __________ in _________ by hunter gatherers in caves. Ancient farmers would plant corn kernels (seeds) with descríbale traits to grow corn.

Desirable traits in corn

Tightly attached seeds; many seeds per ear arranged in rows; big seeds; larger plants; better tasting kernels.

Teosinte

A grass that is corn’s wild ancestor that is genetically similar to corn. Genetic changes in it led to the corn we know today.

Traditional Breeding and Genetic Engineering

How do we select for desirable traits in plants?

Selective Breeding

Type of traditional breeding. Waiting for mutations to happen and selecting the best seeds.

Mutagenesis

Type of traditional breeding. Using chemicals or radiation to produce random mutations that may lead to a better plant.

Genetic Engineering

New genes are inserted. These genes come from other species with desirable traits. Very specific genetic modifications are made using this type of technology. Genetic changes are not random.

plasmid

A circular piece of DNA ; acts as a vehicle to carry the gene. Identified Gene is cut out and isolated, along with a part of a vector. The vector and isolated gene come together as this which turns into recombinant DNA. This DNA is inserted into the desired host cell (for ex. Corn cell) The cell then becomes a protein.

transformation

Process where the plasmid (DNA) is placed into a living bacterial host cell so that protein synthesis can occur (DNA—>RNA—>protein). Bacteria is used since their cells grow very quickly and will rapidly reproduce, making lots of copies of the plasmid (DNA) and protein.

Factor VIII

A genetically engineered protein that is needed as a replacement for blood clotting in hemophiliacs.

Improved nutrition, herbicide resistance, pathogen resistance, improve quality

Why are plants genetically modified?

Improved nutrition

Beta carotene—the compound essential for providing Vitamin A—was cut out of carrots and modified to rice, thus creating Golden Rice. Vitamin A is essential for vision, therefore this helps children obtain Vitamin A in countries where rice is the predominate food source.

Herbicide Resistance

Soybean and others are resistant to herbicide glyphosate (weed killer roundup) because of genetic modification. The weed killer can now kill weeds without killing the crops.

Pathogen Resistance

In corn, an insecticidal protein was added to kill corn borers. Papayas were further genetically modified to resist the ring spot virus,

Improve quality

Apples and potatoes do not bruise or turn brown when cut because of genetic modification.

Bacillus thurigienisis (Bt)

A bacterium called __________________ makes an insecticide that kills corn borers that destroy corn. Furthermore, if corn had this insecticide, it would be able to kill corn borers. Scientists figured they can make the bacterium and insert the insecticide gene into corn.

instructions to make

The gene itself does not contain insecticidal activity. The gene is just ________________ the insecticidal protein.

1

Genetically modified corn contains _________ additional gene(s).

Cell nucleus, Chromosomes, DNA, Genes

Match:

Recipe book—>Chapters—>Letters in the Book—>Recipe

Nucleus

Part of a cell that contains genetic material.

Genome

All the genetic material (DNA) in a cell. Contains all the information needed to build and maintain an organism.

Chromosomes

A “package” of DNA in the cell. Thread-like structures in the nucleus that are made up of DNA tightly wound around proteins called histones. Humans have 23 pairs.

E. coli

singular circular chromosome. 4,288 genes. Stretched out the DNA is 1 millimeter, 1000 times longer than the cell.

Human cell

23 chromosomes. Approximately 20,000-25,000 genes. Stretched out DNA is 6 feet, 180,000 times longer than the cell.

10 32,000

Corn has ____ chromosomes and ________ genes + 1 modified gene.

DNA

deoxyribonucleic acid. Made up of four different nucleotides A, T, G, C. It is a double helix with two long polymers of nucleotides bonded together.

Gene

A segment of DNA that contains the instructions to make a protein. Letters (nucleotides) are arranged in a certain order to form a “recipe” for a protein.

The central dogma

DNA—>RNA—>protein

Transcription

DNA to RNA. An RNA copy of the gene is made in the nucleus. This RNA copy is called the mRNA or messenger RNA.

RNA polymerase

an enzyme that reads code from DNA and makes an RNA polymer—or long chain of nucleotides (A, U, C, G).

messenger RNA

The RNA polymer, or mRNA, is an intermediate step and contains the recipe for the protein.

Translation

RNA to protein. The mRNA moves to the cytoplasm where it is used to synthesize proteins in the cell’s ribosome.

Ribosomes

The “protein factory” in the cell. mRNA code is translated into proteins in these.

proteins

A long chain of chemicals called amino acids. They are the work force of the cell and are critical to metabolism, growth, and structure. (Ex. Collagen, keratin, melanin, hemoglobin, lactase, antibodies, insulin).

Interpreting the Code

During translation, tRNAs interpret the mRNA recipe and bring in the amino acids. These amino acids are connected through chemical bonds and long chains to produce proteins. 20 amino acids make up a protein.

One

______ gene contains the instructions to make _______ protein.

are

GMOs ______ healthy and safe as studies show they present no risk to human health, but further have a positive impact on human health. Genetically modified corn posses enhanced grain quality, have no effect on non-target organisms, and reduce human exposure to mycotoxins.

Reasons Countries Ban GMOs

Poor public understanding of science; pressure from activist; politicians yield to public opinion; negative public perception; discontent with the food and agricultural companies; etc.

Reasons to GMO

Produce plants with improved traits; enable researchers to learn more about a gene’s function and protein production; produce desired proteins in a tube (vaccines/drugs) potentially cure single gene diseases (Sickle Cell Anemia, cystic fibrosis); treat cancer; etc.