Nutrients and gene regulationFrom DNA to Living CellsThe GenomeStrands of all the DNA (deoxyribonucleic acid)Contains all genetic information in the body, housed in cell nucleus and mitochondriaGene does not equal genome: genes are the DNA sequences in the genome that are expressed in the form of protein or RNA (to a limited extent).Not all DNA sequences in the genome are expressedHow many genes we have?RNA (Ribonucleic Acid)Three major types:The intermediate product of the gene after transcription1) messenger RNA (mRNA): intermediates between genes and proteinsfunctional units required for translation2) Transfer RNA (tRNA): carry amino acids3) Ribosome RNA (rRNA): part of ribosomeDNA vs. RNAWatson and Crick, 1962 Novel Prize in physiology or medicineStructural Differences between DNA and RNA1) ribose but not deoxyribose2) Uracil replaces TThe Endless ATGC combinations make life possibleIn 1968, Nirenberg & Khorana were awarded the Nobel Prize for the elucidation of the GENETIC CODEGene ExpressionHow genetic information can be faithfully transmitted?A matches with T(U)G matches with Ctranscription : DNA mRNAtranslation: mRNA proteintRNA and rRNA : assist in translationGene Expression SummaryNuclear DNA makes mRNA copymRNA leaves nucleus –DNA stays behindMRNA attaches to ribosomes (composed of rRNA)tRNA has been collecting AA from cytoplasmtRNA’s give up their AA to the proteins being synthesized in the ribosomean enzyme then bonds one AA to the nextthe protein is then releases if the stop codons followHow is Nutrition related to genetics?Vitamins work at the genetic level to turn gene expression on or offSome nutrients when in excess can cause damage on DNASome antioxidant nutrients can counteract oxygen free radicals and thus inhibit oxidation on DNANutrient involved in Gene ExpressionSeleniumIronSome amino acids (phenylalanine)Vitamin d/ calciumNutrient Regulation of Gene Expression at Transcriptional LevelWhy vitamin D can increase calcium bioavailability?Nutrient Regulation of Gene expression at Translational LevelIronIron effects mRNA translation of protein involved in iron storageWhen iron is high, mRNA of an iron storage protein undergoes translationWhen iron in low, MRNA of an iron storage protein is blocked from translationSeleniumSelenium deficiency results in selenoprotien mRNA degradationNutrigenomicsThe study of how naturally occurring chemicals in foods alter gene expression in each individualIdentification and understanding of population differences and similarities in gene expression, or phenotype, in response to dietHow is nutrition related to human genetic diseases?Defects in genetic code cause nutrition related diseases (mutations)Hereditary hemochromatosisA human autosomal, recessive disorderCause: excessive iron accumulation due to mutations in genes involved in iron apportionSymptoms:Liver cirrhosis, cancer, diabetes, and heat failurePhenylketonuriaInborn error of metabolismPhenylketonuria (PKU) – a genetic disorder, with mutations in the gene that metabolites phenylalanineBuild up of phenylalanine results in brain damageWhat is the dietart limitation for PKU patients?P 71What doe “autosomal recessive” mean?Sickle Cell DiseasePoint mutationEpigeneticsThe science of heritable changes in gene function that occur without a change in the DNA sequenceModifications on DNA (methylation on cytosine, one of the four DNA bases)Modifications on histone proteins (for example, acethylation on histone)Two epigenetic factors and gene activity1. Methylated cytosine: decreased gene expression2. Histone modifications: histone more packed- decreases gene expressionDNA methyl group and gene expression: effect of dietThe B vitamins folate and B12 are essential for transferring methyl groupsSignificance of nutrigenomicsEarly detection may aid with prevention, or may cause undue worryIdentification of specific genes may better focus treatmentCan use as better assessment of nutritional statusUse to set RDAs more accuratelySustainability: Agriculture, nutrition, and foodOur diets and the environmentLarge scale conventional farmingConventional farming depletes soil of nutrientsFertilizer runoff causes algae overgrowth (dead zones)Pesticides and herbicides kill insects and native plantsLoss of land , environmental destruction (desforestation)Energy intensiveIn the US, the food industry uses 20% of the nations fuels to run farm machinery and produce fertilizers and pesticides and to prepare, package, transport, refrigerate, and otherwise sore , cook , and wash our foodssolutions :organic, sustainable, locally growth produceFood Processing6,560 calories of fuel are used to produce a can of corn2,100 calories of fuel are used to produce a diet soda500 for the soda1600 for the cansolution: eat food that is less processedLarge Scale Meat ProductionManure results in soil and water pollutionAnimal are fed grain1/5 of all cropland in the US is used to produce grain for live stock (more than for people)energy intensivetakes eight pounds of grain to produce one pound of weight gain in a cowgreenhouse gasthe amount of pollution produced by a cow is comparable to that by a car in a daysolution : eat less meat, if eating meat find a locally/ sustainably raised grass red optionwater bottlesenergy efficient dishwashers,only running full onereusable grocery bags , pans, dishes rather than disposablesReduce, Reuse, RecycleThe future of oil?“extreme oil” ma replace dwindling supplies but it comes at a heavy cost to economy and environmentOil and foodsPeak oil in the phenomenon were by global oil supplies will peak then decline with extraction growing increainly in costToday’s globalized industrial food system depends on oil for fueling farm machinery producing pesticides, and transporting goodsBiofuels production links oil prices to food pricesAdaptations of food systems for peak oil eraReduce oil in food productionIncreases food system energy effiency and renewable energyChange food consumption patter- “low oil foods”Reduce food transportation distanceRenewable energy: glucose ethanol fuelIs there a road ahread for biofuels?Technology (x3)Carbohydrate fuelDreams/goals: to crack the cellulose and lignin that make grasses, cornstalks, and wood chips into ethanol instead of using corn kernelAlternative energy: Algae BiofuelWhy algae?Grow rapidly: turn carbon dioxide and sunlight into oilNot picky about water qualityNo need for nutrient rich land: little no
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