NFSC100The Genome- Strands of ALL the DNA (deoxyribonucleic acid)- DNA- Contains all genetic information in the body, housed in the cell nucleus and mitochondria- Genes are the DNA sequences in the genome that are expressed in the form ofprotein or RNA- We have about 46 chromosomes (23 pairs)RNA (Ribonucleic Acid)- Messenger RNA: Intermediates between genes and proteins- Transfer RNA: carry amino acids- Ribosome RNA: part of ribosome- Both tRNA and rRNA are functional units required for translationDNA vs. RNA- Structural differences: Ribose (RNA) not deoxyribose (DNA)- Uracil (U) replaces TGene Expression- How genetic information can be faithfully transmitted- A matches with T (U)- G matches with C- The DNA serves as a template to make strands of mRNA- The mRNA exits the nucleus of the cell through the nuclear membrane, while the DNA stays inside the nucleus- The mRNA attaches itself to the ribosomes, while the tRNA collects amino acids from the cell fluid and brings them to the messenger- When the mRNA calls for an amino acid, the tRNA carries it and snaps it into position- 40 to 100 amino acids can be added to a growing protein strand in 1 second- Transcription: DNA to mRNA- Translation: mRNA to protein- tRNA and rRNA: assist in translationHow is Nutrition related to genetics?- Vitamins work at the genetic level to turn gene expression on or off- Some nutrients when in excess can cause damage on DNA- Nutrients involved in gene expression- Selenium, iron, phenylalaine (some amino acids), Vitamin D/CalciumNutrient Regulation of Gene Expression- Transcriptional Level: Vitamin D- Regulates calcium absorption- Translational Level: Iron- When iron is high, mRNA of an iron storage protein undergoes translation- When iron is low, mRNA of an iron storage protein is blocked from translation- Translational Level: Selenium- Deficiency results in mRNA degradationNutrigenomics- The study of how naturally occurring chemicals in foods alter gene expression in each individual- Understanding of differences and similarities in gene expression in response to diet- Defects in genetic code cause nutrition related diseases (mutations)- Hemochromatosiso Excessive iron accumulation due to mutations in genes involved in iron absorptiono Symptoms: liver cirrhosis, cancer, diabetes, and heart failure- Phenylketoniuria (PKU)o Inborn error of metabolismo Build up results in brain damageo Dietary limitation—limited intake of protein- Sickle Cell Diseaseo One amino acid in the protein strands of hemoglobin takes the place of another, causing the red blood cell to change shape and lose functionSignificance of Nutrigenomics- Identification of specific genes may better focus treatment- Use to set RDA’s more accuratelyEpigenetics- The science of heritable changes in gene function that occur without a changein the DNA sequence- Modifications on DNA (Methylation on cytosine, leads to less gene expression)- Modifications on histone (histone more packed leads to less gene expression)- Epigenome consists of proteins and other molecules that act to regulate the expression of genes on the strands of DNA—turning the genes on or off (doesnot change DNA sequence)- DNA Methyl group and gene expression: effect of diet- The B vitamins Volate and B12 are essential for transferring methyl groupsOur Diets and the Environment- Large scale conventional farming- Depletes soil of nutrients- Fertilizer runoff causes algae overgrowth (dead zones)- Pesticides and herbicides kill insects and native plants- Loss of land, environmental destruction (deforestation)- Energy intensive—US food industry uses over 20% of the nations fuels - Food Processing- 6560 calories of fuel used to produce a can of corn- 2100 calories of fuel used to produce diet soda- Solution: Eat less processed foods- Large Scale Meat Production- Manure results in soil and water pollution- Animals are fed grain—1/5 of all cropland in the US is used to produce grain for livestock (more than for people)- Energy Intensiveo Takes 8 lbs of grain to produce 1 lb of weight gain in a cow- Greenhouse gaseso The amount of pollution produced by a cow is comparable to that by a car in a day- Solution: eat less meat, if eating meat, find locally/sustainably raised, grass fed- Use water bottles, energy efficient dishwashers, reusable grocery bags, reusable pans, recycleOil and Foods- “Extreme oil” may replace dwindling supplies, but it comes at a heavy economic and environmental cost- Peak oil is the phenomenon whereby global oil supplies will peak, then decline, with extraction growing increasingly costly- Today’s globalized industrial food system depends on oil for fueling farm machinery, producing pesticides, and transporting goods- Biofuels production links oil prices to food prices- To Adapt:- Reduce oil in food production- Increase food system energy efficiency and renewable energy- Change food consumption pattern—“Low oil foods”- Reduce food transportation distanceRenewable Energy- Glucose—ethanol fuel- Sugarcane—yeast—sucrose- Corn—enzymes and yeast—starch- Cornstalk, grass, wood chips—challenging—cellulose- Carbohydrates possible used as fuel eventually- Goal: to crack the cellulose and lignin that make grasses, cornstalks, and wood chips into ethanol instead of using corn kernelAlgae Biofuel- Algae grows rapidly, turns carbon dioxide and sunlight into oil- Not picky about water quality- No need for nutrient rich land, little to no competition with food production- Lower carbon dioxide green house gasUSDA Certified Organic- The National Organic Standards Board (NOSB) - USDA prohibits use of toxic and persistent chemicals in favor of more earth friendly practices- Crop rotation- Planting cover crops- Releasing beneficial insects- Adding composted manure- Field must be free of synthetic pesticides and fertilizers for 3 years before a certified organic crop can be grown on it- Use of proper manure- composting techniques to prevent against foodborne illness- Organic eggs, meats, and dairy products must be from animals that are given 100% organic feed- Severe confinement is forbidden- No antibiotics or growth hormones- Organic food may not be 100% free of pesticides because they are pervasive in the environment- Organic products are not higher in vitamins and minerals- Labeling- 100% organic must contain only organically produced ingredients- Organic must consist of at least 95% of organically produced ingredients- Made with Organic
View Full Document
Unlocking...