Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
DNA Structure Structures + #ing of nucleic acids Proofreading 5 principal bases in Base Excision repair Nucleotide structure in DNA Mismatch repair Transcription Complementary base pairs that exist in DNA, + # Holoenzyme: core + sigma factor of H bonds. Basal promoters: euk vs prok? DNA Synthesis 1. DNA denatured at replication origin. RNA poll, II, III : function, amanitin sensitivity Terminators How many on in eukaryotes vs. prokaryotes? Gene Regulaton Operon, polycistronic message What’s in replisome in prok,? euk? Function of each one? 2. Primer Synthesis DNA primase -- de novo synthesis Leading vs lagging Introns, splicing, spliceosomes Capping Lac operon Translation strand tRNA: intrastrand base pairing 3. Chain Synthesis aminoacyl tRNA synthetases: function. how many? Order of events Function, processivity, + exonuclease activity of DNA poll, DNA ~Ol III, DNA poi alpha, delta, + epison A site - P site Peptide bond formation Energy requirements DNA Synthesis Fidelity Wobble Rules What’s the result + related disease for: frameshift.and nonsense mutation Antibiotics Disease Type 0 Enzyme Affected Glycogen Synthase Type I (Von Guirke’s) Glucose-6-P Phosphatase Type IV (Anderson’s) Lack of Branching Enzyme Type V (McArdle’s) Muscle Phosphorylase MODY Glucokinase (maturity-onset diabetes) EFT or EFT:CoQ reductase defieciency Carnitine Deficiency EFT or EFT:CoQ reductase Carnitine . CAT-I Deficiency Carnitine Acyl-Transferase I MCAD Deficiency Medium Chain Acyl-C0A Dehydrogenase G-6-P Dehydrogenase defieciency Beriberi G-6-P Dehydrogenase Wernicke-Korsakoff Transketolase: nutritional shortage of thiamine Transketolase: thiamine shortage. Symptoms Hypoglycemia Hypoglycemia Enlarged Liver Gout Cirrhosis of Liver due to insoluble glycogen Weakness after exercise Hyperglycemia; higher glucose % needed for insulin release. Death: Inability to harness energy from FADH2 Weakness and muscle cramping; elevated F.A. levels in blood wlo elevated ketones or dicarboxylic acids High F.A. in plasma, no ketone bodies. Hypoglycemic after fasting. Hypoglycemia; high medium chain in urine. Low energy levels due to inability to fully oxidize F.A. Anemia during drug treatment. Fluid retention, pain and paralysis. Neuronal dysfunction, found mostly in alcoholics Type I Diabetes Insulin Hyperglycemia Type II Diabetes Insulin Receptor (non Hyperglycemia functional) ~ Acanthosis nigrecans Insulin Receptor (Ab Hyperglycemia against receptor created) Treatments Small frequent meals. Liver Transplant Carnitine in diet High Medium Chain Fatty Acids in diet. Frequent, small meals Thiamine in diet. Reduce alcohol increase, thiamine in diet. Injection of insulin Diseases Eukaryotes Prokaryotes “Simple” RNA polymerase enzyme (subunit composition o~3~’ao) transcribes all genes Complex RNA polymerases 3 species poll 5.8S, 18S, 28S rRNA pol II protein-encoding genes (mRNA) p01 III tRNAs, 5S RNA - - - - a protein recognizes promoter (-35 and -10 consensus) in context of holoenzyme a factor leaves “holoenzyme” after approx. 10 phosphodiester bonds synthesized elongating - polymerase is the “core” enzyme No processing of mRNA • no capping • no splicing • no polyadenylation Termination through either p-dependent or independent pathways polil promoter typified by TATA box at -30; recognized by TFIID factor pol II binds subsequently along with other TF’s - Most TFII factors remain at promoter as polymerase II commences elongation, BUT TFIIH accompanies polymerase (contains helicase activity) Processing of mRNA • capping at 5’ end • • splicing of introns termination through polyadenylation No comparable mechanism (see polyadenylation) Transcription (and processing to mature mRNA) occur in nucleus transport to cytoplasm required for translation - No nucleus, therefore coupled transcription and translation Monocistronic organization of genes variant proteins can be produced through alternative - Genes frequently organized in polycistronic arrays - single mRNA can produce multiple proteins, often have related functions, e.g. lac operon Gene expression regulated primarily through transcriptional initiation control Transcriptional control mediated through balance of activating and repressing activities in “transcription factors” that bind to DNA regulatory elements splicing Gene expression regulated at many points, e.g., transcription control, mRNA stability, alternative splicing, mRNA transport Prokaryotic paradigm of combinatorial control of levels of gene transcription through transcription factors appears to hold. DNA regulatory elements often much more complex, Comparin2 transcription and gene re~u1ation in prokarvotes an(1 euKaryotes e.g., proximal promoter elements, enhancers, locus control regions. Comparin2 replication in prokaryotes and eukaryotes Eukaryotes Prokaryotes Circular chromosomes have single origin of replication ‘-1000 Linear chromosomes have multiple origins of replication nucleotide/sec Slower rate of replication -~100 nucleotide/sec DNA polymerase III is the main synthetic enzyme works on both leading and lagging strands DNA polymerase y/~ is/are the main synthetic enzymes work on both leading and lagging strands DNA primase synthesizes RNA primer primer ‘~l0 nucleotides long DNA primase/pol a synthesizes mixed primer composed of short RNA chain followed by short DNA chain primer —‘20 nucleotides in length Replication extremely fast - - - - - - - DNA polymerase I eliminates RNA primer through its 5’-->3’ exonuclease activity, synthesizes DNA in its place DNA polymerase I also important in base and nucleotide excision repair RNA primer eliminated by a distinct 5’-->3’ exonuclease protein DNA resynthesized by polymerase ‘y/ö - DNA polymerase used for most repair Comparin2 transcription and gene re~u1ation in prokarvotes an(1 euKaryotes RNA synthesis DNA synthesis Multiprotein enzyme complex loads at origin of replication Multiprotein enzyme complex loads at promoter (1 species in prokaryotes, 3 species in eukaryotes No primer required Primer required/DNA primase Only rNTP’s required All dNTP’s and rNTP’s required Mg2-dependent process Mg2~-dependent process Only one strand of DNA acts as template Both strands of DNA act as template, i.e., is bi-directional - selection depends on promoter sequence Synthesis is 5’-->3 Synthesis is 5’-->3’ Template read in 3’-->5’ direction Template read in 3’-->5’ direction Only continuous synthesis Continuous or discontinuous synthesis dependent on strand No proofreading Proofreading/3’-->5’ exonuclease Not relevant to process Okazaki fragments/DNA ligase differ between prokaryotes and eukaryotes Stop signals of various kinds Stop signals not defmed - Always uses Watson-Crick base pairs