This presentation was prepared using draft rules. There may be some changes in the final copy of the rules. The rules which will be in your Coaches Manual and Student Manuals will be the official rules.
• BE SURE TO CHECK THE 2013 EVENT RULES for EVENT PARAMETERS and TOPICS FOR EACH COMPETITION LEVEL TRAINING MATERIALS: • Training Power Point presents an overview of material in the training handout • Training Handout presents introductory topic content information for the event •Sample Tournament has sample problems with key Event Supervisor Guide has event preparation tips, setup needs and scoring tips • Internet Resource & Training Materials are available on the Science Olympiad website at www. soinc. org under Event Information. • A Biology-Earth Science CD as well as the Division B and Division C Test Packets are available from SO store at www.
soinc. org Students will solve problems using their knowledge of Molecular Genetics, Biotechnology, and Population Genetics. This event may be run as stations but it need not be.DNA polymerase also has proofreading activities, so that it can make sure that it inserted the right base, and nuclease (excision of nucleotides) activities so that it can cut away any mistakes it might have made.
• Primase attaches a small RNA primer to the single-stranded DNA to act as a substitute 3'OH for DNA polymerase to begin synthesizing from. This RNA primer is eventually removed and the gap is filled in by DNA polymerase (I). • Ligase can catalyze the formation of a phosphodiester bond given an unattached but adjacent 3'OH and 5'phosphate. This can fill in the unattached gap left when the RNA primer is removed and filled in.
Single-stranded binding proteins are important to maintain the stability of the replication fork. Single-stranded DNA is very labile, or unstable, so these proteins bind to it while it remains single stranded and keep it from being degraded. Nuclear vs Cytoplasmic DNA in Eukaryotic Cells • Nuclear DNA – in chromosomes within the nucleus of the cell • Cytoplasmic DNA – in chloroplasts and mitochondria • Chloroplast DNA (cpDNA) • Mitochondrial DNA (mtDNA) • Features: • Maternal inheritance • Resemble prokaryotic DNA • Slow accumulation of mutations • Differences between RNA ; DNA • RNA is single strand - DNA is double strand • RNA has Ribose – DNA has Deoxyribose • RNA has Uracil – DNA has Thymine Gene ExpressionThere are two processes with utilize the DNA template code to ultimately produce proteins: • Transcription – DNA is template for making RNA (in nucleus) There are 3 types of RNA. • Translation (protein synthesis) - in cytoplasm at the ribosome. M-RNA has blueprint, T-RNA transfers amino acids, and Ribosome (R-RNA) allows T-RNA to attach to M-RNA at appropriate site. • many factors control gene expression including: o factors affecting DNA structure, o gene expression, o factors affecting assembly of proteins after o translation, o hormones, o environmental factors as viruses.
Types of RNA Kinds of RNA – three kinds of RNA are produced in the nucleus using DNA coding strands Messenger RNA (m-RNA) – carries genetic code from DNA into cytoplasm • Transfer RNA (t-RNA) – brings the amino acids for building of protein to be attached according to the genetic code of the M-RNA • Ribosomal RNA (r-RNA) – make up the ribosome and reads the code of M-RNA and allow T-RNA to attach and connect amino acids Transcription Transcription - production of RNA in the nucleus using a DNA segment as a template and RNA polymerase as the key enzyme. Post-transcription Modifications RNA’s are modified in eukaryotes before leaving the nucleus. • PreM-RNA has exons (coding segments) and introns (noncoding segments between exons) • introns (the noncoding segments) are removed • a cap is added to the 5’ end • a polyA tail is added to the 3’ end before it leaves the nucleus Universal Code (Codon = Amino Acid) [pic] Each three base codon on the messenger RNA (m-RNA) is a code for an amino acid • There are 64 possible three base codons – 61 are codes for one of the 20 amino acids • The three remaining codons are termed stop codons because the signal the end of a peptide segment • Notice that many of the amino acids have more than one codon • A three base code on the DNA produces the mRNA codon •The three base code on the t RNA is termed an anticodon because it will bond to a m-RNA codon during translation or protein synthesis Translation (Protein Synthesis) Translation – genetic code used to form amino acid sequence using M-RNA, T-RNA, and R-RNA (ribosomes) occurs in the cytoplasm at the ribosome. Many key enzymes (proteins) are involved.
Translation (Protein Synthesis) The steps of translation: • Initiation: a mRNA enters the cytoplasm and becomes associated with ribosomes (rRNA + proteins) and tRNAs, each carrying a specific amino acid, pair up with the mRNA codons inside the ribosomes. The base pairing (A-U, G-C) between mRNA codons and tRNA anticodons determines the order of amino acids in a protein. Elongation: involves the addition of amino acids one-by-one:As the ribosome moves along the mRNA, each tRNA transfers its amino acid to the growing protein chain, producing the protein • Termination: when the ribosomes hits a stop codon - UAA, UGA, or UAG - – no tRNA with its amino acid can be added so the ribosome falls apart and the process ends. The same mRNA may be used hundreds of times during translation by many ribosomes before it is degraded (broken down) by the cell.
A close up showing the M-RNA (with its codon) and T-RNA (with it anticodon as well as the Amino Acid) attaching at the P and A sites on the Ribosome. Control of Gene Expression • Transcriptional Control • Post transcriptional Control – assembling proteins • Cell differentiation and specialization Turning genes “on” and “off” • Chemical Signals – Hormones • Chemical Modifications • Relocation of DNA – transposons • Abnormal Expression of Genes Mutations • Gene – section of DNA with carries the blueprint for making a peptide strand or RNA. • Mutation – changes in genetic code (DNA blueprint) of genes or chromosomes and causes changes in expression in the for making protein or RNA • Gene mutation • Chromosomal mutation • Agents causing mutations – radiation, chemicals, excess heat , viruses Genetic Disorders •Nondisjunction – extra or missing chromosomes as Down’s Syndrome • Trinucleotide repeats – triplet nucleotides • repeated too often as Huntington’s Defective genes – does not produce correct protein as sickle cell anemia (A ; T traded places) • Causes of mutations – chemicals, radiation, temperature, viruses • Genetic disorders and their causes as nondisjunction (Down’s syndrome), trinucleotide repeats (fragile X and Huntington’s), defective genes (sickle cell anemia, hemophilia) • Trinucleotide repeats – sequences of 3 nucleotides is repeated, often several times in a gene, • when too many repeats are formed – cause genetic disorders • Nondisjunction – chromatids do not separate properly during meiosis. Individual formed from such gametes have extra or missing chromosomes. • Human genetic disorders – can be dominant, recessive, sex-linked, epistatic, variable expressed • Crossover frequency – during meiosis, pieces trade places – determining frequency Mitochondrial Inheritance – genetic make-up of mitochondria, genetic code and patterns transmitted through mother.
The inheritance of a trait encoded in the mitochondrial genome •Mitochondrial DNA or mtDNA is inherited from the mother • The mtDNA is circular and resembles prokaryotic DNA • The mitochondria are responsible for energy production • Mitochondria can reproduce independent of the rest of the cell – an advantage in energy production • Persons with a mitochondrial disease may be male or female but they are always related in the maternal line and no male with the disease can transmit it to his children • Mitochondrial myopathies are a group of neuromuscular diseases caused by damage to the mitochondria-small, energy-producing structures that serve as the cells' "power plants. " Lac & Trp Operons - examples of prokaryotic gene regulation • Many of the prokaryotic genes as in E. coli are expressed or are always turned "on". Others are active only when their products are needed by the cell, so their expression must be regulated. • Examples of Operons in E. coli o The genes for the five enzymes in the Trp synthesis pathway are clustered on the same chromosome in what is called the Trp Operon - If the amino acid tryptophan (Trp) is added to a culture of E coli , the bacteria soon stop producing the five enzymes needed to synthesize Trp from intermediates produced during the respiration of glucos so the presence of the products of enzyme action represses enzyme synthesisThis is a repressable operon where genes are expressed in the absense of a substance and the presense of the substance shuts off the gene The genes that code for the enzymes needed for lactose catabolism are clustered on the same chromosome in what is called the Lac Operon – prokaryotics as E.
coli have a mechanism for metabolizing lactose – the sugar used for energy. Three proteins or enzymes are needed in lactose metabolism and they are encoded in a single expressible unit of DNA called the lac operon The E. coli only express the genes and make these enzymes when lactose is available to be metabolized. This is an inducible operon where genes are expressed in the presence of a substance Biotechnology – technology to manipulate DNA – techniques often called genetic engineering or Recombinant DNA Technology. • Technology used to manipulate DNA •Procedures often called genetic engineering • Recombinant DNA - DNA from two sources Transgenic individuals have DNA from another organism • Often involve putting genes into viruses or bacteria.
• Vectors are the pieces of DNA used to transfer genes into a host cell – often plasmids of bacteria Overview of Biotechnology Basic Tools of DNA Technology • Identifying desired DNA • Cutting DNA with Restriction Enzymes • Inserting DNA into Vector as Plasmid • Connecting DNA pieces with Ligase • Inserting Vector into Host Cell as bacterium • Cloning desired DNA and Vectors • Storing clones in DNA Libraries • Identifying cloned genes with Radioactive Probes • Analyzing DNA by cutting fragments and separating by Electrophoresis.
