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  • 1. UNIT 4<br />Molecular Biology<br />Study guide<br />This study guide outlines some of the topics, ideas and skills that will be on the Unit test. Test materials ARE NOT LIMITED to the items on this list. All information given in lectures, homework, assigned readings, worksheet or labs may be on the test and it is recommended that you study all of the work we did in this unit.<br />Content of the unit<br />Chapters 11, 12, and 13<br />DNA structure reviewDNA replicationThe central dogma of BiologyRNA structure reviewTypes of RNATranscriptionTranslationMutationsHuman geneticsDNA technologies<br />DNA review <br />DNA= deoxyribonucleic acid<br />Monomer=nucleotide<br />A nucleotide has:<br />Ring-shaped sugar=deoxyribose <br />Phosphate group<br />Nitrogenous base<br />Nitrogenous bases <br />Pyrimidines (single ring)<br />Thymine (T)<br />Cytosine (C)<br />Purines (double ring)<br />Adenine (A)<br />Guanine (G)<br />Structure of DNA<br />Nucleotides form DNA strands <br />Covalent bonds connect a sugar from a nucleotide with the phosphate of the next<br />Sugar-phosphate-sugar-phosphate…. Form the “backbone”<br />Nitrogenous bases are lined up along backbone (ladder analogy)<br />The Double Helix <br />Rosalind Franklin, Watson , and Crick<br />2 strands of nucleotides form a twisted structure<br />Complementary bases pair up <br />Form H bonds<br />A pyrimidine (1 ring) always pairs with a purine (2 rings)<br />A – T<br />C – G<br />DNA replication <br />interphase<br />DNA polymerases<br />starts in origins of replication<br />goes in both directions simultaneously forming replication bubbles<br />each strand opens to serve as templates of daughter strands<br />The central dogma <br />DNA is transcribed into RNA and the RNA is translated into a protein…<br />RNA review <br />Ribonucleic acid<br />ribose<br />RNA has no T base instead has uracil (U) (U pairs up with A)<br />Single strand<br />Types of RNA <br />mRNA<br />tRNA<br />rRNA<br />TRANSCRIPTION <br />DNA’s nucleotide sequence is converted into a single-stranded RNA form<br />the 2 DNA strands separate where transcription starts <br />RNA bases pair with complementary DNA bases <br />The U in RNA pairs with the A in DNA <br />RNA polymerase links the RNA nucleotides together <br />Specific sequences of DNA tell the RNA polymerase where to start and finish the transcription <br />Eukaryotes mRNA edition <br />mRNA is edited before leaving the nucleus <br />Splicing of introns (non coding sequences) <br />Exons are joined together<br />TRANSLATION <br />Converts the nucleic acid language (RNA) into and aa language<br />By codons= 3 bases code for an aa <br />How to use the codon chart <br />Participants in translation<br />tRNA <br />translates the three-lettered codons of mRNA into the aa that make up the proteins <br />tRNA molecule carries the anticodon in one end <br />Anticodon=sequence that is complementary to a specific codon in mRNA <br />The other end of tRNA site where a particular aa attaches <br />A specific enzyme recognizes the tRNA with the aa and links two aa together <br />ATP is needed in this process <br />Ribosomes <br />A ribosome consists of 2 subunits <br />Each subunit is made of proteins and rRNA <br />The ribosomes hold mRNA and tRNA close together <br />Translation-the process <br />All parts get together: <br />2 ribosomal subunits <br />mRNA <br />tRNA + aa attached <br />starting codon AUG <br />aa are added one by one to a growing polypeptide chain <br />stop codon UAA, UAG, UGA <br />polypeptide chain is freed <br />Mutations<br />changes in the nucleotide sequence of DNA <br />Two types of mutations <br />substitution<br />deletion or insertion<br />Causes for mutations <br />DNA replication <br />Chromosomes crossing over during meiosis <br />Mutagens: physical and chemical agents that cause mutations <br />i.e. radiation <br />mutations are the basis for genetic variation therefore for natural selection<br />Human genetics <br />Human genome project <br />1990 starts <br />2000 draft of entire human genome was sequenced <br />It works to: compare genomes and understand evolutionary history <br />Human health: for the diagnose, treatment, and prevention of diseases such as: allergies, diabetes, and cancer <br />Nondisjunction <br />Malfunctioning during meiosis <br />Nondisjunction: homologous chromosomes (meiosis I) or sister chromatids (meiosis II) fail to separate <br />Results in abnormal number of chromosomes <br />The sex cells have different number of chromosomes <br />Causes: ?¿ <br />example: Down syndrome <br />Chromosome damages <br />Changes in chromosome structure can cause disorders <br />Chromosomes can change by duplication, deletion, inversion, and translocation <br />Transposons or jumping genes can cause disorders too <br />Human pedigrees <br />Tool used to track down traits collecting familiy history <br />A pedigree records and traces the occurrence of traits in a family <br />Squares=males, circles=females <br />Colored shapes=trait <br />Looking at generations it is possible to determine genotypes <br />i.e. pedigree tree for attached ear lobes <br />also used to analyze disorders <br />Genetic diseases <br />Genetics and cancer <br />Cell cycle is regulate by: <br />Growth factors: genes that initiate cell division <br />Tumor-suppressor genes: code for proteins that stop cell division <br />Accumulated mutations in these genes can lead to cancer <br />Genes affected become Oncogenes=cancer causing gene <br />Genetic diseases <br />Research project and presentations<br />Topics:<br />
    • thalassemiaTay sachsspina bifidasickle cell anemiacystic fibrosishemophiliadown syndromeachondroplasiahuntington diseasephenylketonuria (PKU)cri du chatred green colorblindness
    Useful apps of DNA tehcnology <br />Food sources can become better<br />Simpler organisms research can be extrapolate to what happens in humans<br />Work is usually done in organisms such as:<br />Bacteria<br />Viruses<br />Yeast<br />Fruit flies<br />Certain plants<br />Several steps to get to genome sequencing <br />Introducing genes of interest<br />Normally through plasmids<br />In a process of cutting and pasting DNA<br />Genes are cloned<br />Kept in “libraries”<br />PCR<br />Genes are identified<br />Probes<br />Electrophoresis<br />Genes are sequenced and used <br />Uses <br />Pharmaceutical (e.g. insuline)<br />Medicine (e.g. gene therapy)<br />Diagnosis<br />Agricultural<br />Plants<br />Farm animals<br />Forensic<br />Criminal cases <br />Vocabulary<br />deoxyribosenucleotidenitrogenous basespyrimidinepurinedouble helixDNA replicationDNA polymeraseribonucleic acidtranscriptiontranslationcodonmRNARNA polymeraseintronexontRNAanticodonrRNAmutationmutagengenometrisomy 21Down syndromenondisjunctionpedigreecarriergrowth factortumor suppressor geneoncogeneelectrophoresis<br />Textbook pages to read and answer questions<br />Chapters 11, 12, 13<br />Do Chapter reviews at the end of each chapter<br />