Genetics and Molecular Biology: DNA, RNA, Proteins, and Genetic Engineering, Study notes of Gardening and Horticulture

Download Genetics and Molecular Biology: DNA, RNA, Proteins, and Genetic Engineering and more Study notes Gardening and Horticulture in PDF only on Docsity! THE GENETIC BASIS OF LIFE (From http://generalhorticulture.tamu.edu) Analogy DEFINITIONS DNA (deoxyribonucleic acid)- a double helix chain of sugar-phosphates (deoxyribo sugar-phosphates) connected by nucleic acids (adenine, thymine, guanine, cytosine). RNA (ribonucleic acid) - a single stranded chain of sugar-phosphates (ribo sugar-phosphates) containing nucleic acids (adenine, uracil, guanine, cytosine). nucleic Acids - organic acids that form the base pairs of DNA and single-bases of RNA. Base Pairing of Nucleic Acids between the double strands of DNA A- T (adenine-thymine) G - C (guanine-cytosine) Base Pairing of Nucleic Acids between DNA strands and RNA strands A - U (adenine-uracil) G - C (guanine-cytosine) gene - a length of DNA that codes for the production of a protein or protein subunit. - also codes for active RNAs (such as tRNA). protein - a polymer or chain of amino acids. enzyme - a protein that acts as a metabolic catalyst. 2 The Central Dogma of Molecular Biology (From: http://www.accessexcellence.org) Legend: Transcription of DNA to RNA to protein: This dogma forms the backbone of molecular biology and is represented by four major stages. 1. The DNA replicates its information in a process that involves many enzymes: replication. 2. The DNA codes for the production of messenger RNA (mRNA) during transcription. 3. In eucaryotic cells, the mRNA is processed (essentially by splicing) and migrates from the nucleus to the cytoplasm. 4. Messenger RNA carries coded information to ribosomes. The ribosomes "read" this information and use it for protein synthesis. This process is called translation. Proteins do not code for the production of protein, RNA or DNA. They are involved in almost all biological activities, structural or enzymatic. David Wm. Reed, Texas A&M University 5 Cloning DNA into a Plasmid to Produce Recombinant DNA (From: http://www.accessexcellence.org) Process by which a plasmid is used to import recombinant DNA into a host cell for cloning. The plasmid carrying genes for antibiotic resistance, and a DNA strand, which contains the gene of interest, are both cut with the same restriction endonuclease. They have complementary "sticky ends." The opened plasmid and the freed gene are mixed with DNA ligase, which reforms the two pieces as recombinant DNA. This produces recombinant Deaths recombinant DNA stew transforms a bacterial culture, which is then exposed to antibiotics. All the cells except those which have been encoded by the plasmid DNA recombinant are killed, leaving a cell culture containing the desired recombinant DNA. DNA cloning allows a copy of any specific part of a DNA (or RNA) sequence to be selected among many others and produced in an unlimited amount. This technique is the first stage of most of the genetic engineering experiments: production of DNA libraries, PCR, DNA sequencing, et al. David Wm. Reed, Texas A&M University 6 Using restriction enzymes for Mapping or Finger Printing When DNA from the same source is digested with a particular restriction enzyme it will always give a set of the same sized fragments. For example if lambda bacteriophage DNA is cut with EcoR1 we know that it will give six fragments of the sizes: 21.23, 7.42, 5.8, 5.65, 4.87, 3.53 kbp. This is because, mutations apart, the phage sequence will always be the same, and so EcoR1 cutting sites will always be present in the same places. The fragments can be separated and their sizes determined by agarose gel electrophoresis. We can use the positions of restriction enzyme sites as convenient markers along DNA sequences. The map obtained can be used for DNA identification and to plan DNA manipulations. Finger Printing Gel Showing Banding from use of Different Restriction Enzymes David Wm. Reed, Texas A&M University 7 Genetically Modified Organisms (GMO) or Transgenic Crops (From: http://www.colostate.edu/programs/lifesciences/TransgenicCrops/index.html) Authors: Pat Byrne, Sarah Ward, Judy Harrington, Lacy Fuller (Web Master) Crops and acreage Transgenic crop production area by country (source: James, 2000b) Country Area planted in 2000 (millions of acres) Crops grown USA 74.8 soybean, corn, cotton, canola Argentina 24.7 soybean, corn, cotton Canada 7.4 soybean, corn, canola China 1.2 cotton South Africa 0.5 corn, cotton Australia 0.4 cotton Mexico minor cotton Bulgaria minor corn Romania minor soybean, potato Spain minor corn Germany minor corn France minor corn Uruguay minor soybean David Wm. Reed, Texas A&M University